Geology of Cuba (AAPG Studies in Geology 58)

Overview

Pardo, G., 2009, Overview, in G. Pardo, The geology of Cuba: AAPG Studies in Geology Series, no. 58, p. 1 – 47.

INTRODUCTION

the Instituto Cubano del Petroleo (ICP) and Cubapetroleo (CUPET). After the revolution, Cuba joined the Committee for Mutual Economic Assistance (COMECON), formed by the former Soviet Union and associated countries, and received considerable assistance from Soviet, Polish, Bulgarian, Czechoslovakian, and Romanian earth scientists and technicians. Exploration and drilling became the responsibility of the Instituto Cubano de Recursos Minerales (ICRM), and later of the Empressa de Perforacion y Extraccion de Petroleo (EPEP). These agencies were under the control of the Ministerio de Industrias Basica (MINBAS). A large number of deep wells (3000–5000 m [10,000– 16,400 ft] deep) were drilled in central and western Cuba, many of them (Pozos Parametricos) only for stratigraphic and structural information. Non-Soviet and non-COMECON foreign work began again in 1988, resulting in an increase in exploration and development activity (mostly seismic surveying and drilling). So far, major international oil companies and United States-based companies have not participated. There has been an ongoing program of mapping the entire island conducted under the direction of the Cuban Academy of Science, Institute of Geology and Paleontology, with, formerly, the assistance of the former Soviet Union’s Academy of Science. This program has yielded several publications, mostly in Spanish, but some in English. It also resulted in a 1:500,000 geologic map in 1985 (Cuba, 1985a), an excellent 1:250,000 geologic map in 1988 (Pushcharovsky et al., 1988), a good 1:500,000 tectonic map in 1989 (Pushcharovsky et al., 1989), and a 1:500,000 nonmetallic mineral and combustible deposits and indication map in 1988 (Cuba, 1988). Unfortunately, the Cuban Academy of Science and the Cuban government agencies responsible for petroleum exploration and production do not appear to work together; matters related to petroleum are considered confidential.

The geology of Cuba has been a challenge to geologists because of features such as the presence of well-preserved Jurassic ammonites, the rich Tertiary foraminiferal faunas (including remarkable Paleogene orbitoids), the gigantic Upper Cretaceous rudistids, the spectacular limestone Mogotes of Pinar del Rio, the extensive outcrops of ultrabasic igneous rocks, the chromite and manganese deposits, and the extraordinary structural complexity. In addition to these features, the numerous petroleum seeps, many of them coming out of basic igneous rock, have attracted much attention. It is interesting to read early papers by reputable geologists such as E. DeGoyler (1918), J. W. Lewis (1932), or R. H. Palmer (1945), and to realize how little was known or understood about the geology of the southern portion of the North American continent in the early part of the 20th century. Much early understanding of the geology of Cuba resulted from a series of studies conducted between 1936 and 1946 by the University of Utrecht, Holland, under the direction of L. M. R. Rutten. Some resultant publications are Rutten (1936), MacGillavry (1937), Thiadens (1937a, b), Vermut (1937), van Wessen (1943), Keijzer (1945), Hermes (1945), and De Vletter (1946). These authors outlined the components of a classic geosyncline. Between the late 1930s and late 1950s, Cuban geologists and paleontologists, such as P. R. Ortega y Ros, J. Broderman, P. Bermudez, and J. F. Albear, published several articles about the island’s geology. The search for oil has contributed significantly to the present understanding of the island’s geology. Prior to the 1959 revolution, hydrocarbon exploration was mostly undertaken by international oil companies such as Atlantic Refining, Esso Standard, Gulf Oil, Shell Oil, and the California Oil Company. Late in 1959, the oil company files were copied and confiscated. In 1960, the oil companies were expropriated, and the search for oil became the responsibility of

Copyright n2009 by The American Association of Petroleum Geologists. DOI:10.1306/13141059St583328

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FIGURE 1. Cuba: old provinces.

FIGURE 2. Cuba: new (1976) provinces.

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FIGURE 3. Regional setting.

In 1967, Khudoley (at that time with the former Soviet Union’s Academy of Sciences) published, through AAPG, his concepts and interpretation of Cuban geology. In 1971, Khudoley and Meyerhoff presented their conflicting concepts in a joint article in a Geological Society of America memoir. Contacts between Cuban, American, and international earth scientists have now revived. An example is International Union of Geological Sciences – United Nations Educational, Scientific, and Cultural Organization International Geological Correlation Programme (IGCP) Project 364 and ongoing Project 433 on Caribbean geology. Manuel Iturralde-Vinent, from Havana’s Museo Nacional de Historia Natural, has made significant contributions to the understanding of the island’s geology; not only has he authored papers on several aspects of Cuban geology, but he has written and cooperated on projects by a number of international organizations (Iturralde-Vinent, 1969, 1970, 1972, 1975a, b, 1981, 1985, 1988, 1996, 1998; Iturralde-Vinent and de la Torre, 1990; Iturralde-Vinent et al., 2006), thus dis-

seminating information that was previously restricted to Cuba and eastern European Countries. Until recently, very little has been published in English describing Cuban geology. This is unfortunate because a better understanding of Cuban geology might lead others to become aware of processes not recognized elsewhere. The interpretations presented here are based on models derived from areas such as the Alps or the Pacific. This report presents as much factual material as possible in addition to an interpretation of the data. Cuba is, geographically and geologically, a part of the Caribbean. English-language reviews of Caribbean geology such as those found in Nairn and Stehli (1975) and Dengo and Case (1990) are useful for understanding Cuban geology. Recently, Pindell et al. (2006, p. 304) suggested that much of the Caribbean geology is well understood, and that new evaluations, ‘‘may also partly reflect the involvement of new or younger workers who were not actively involved in much of the older work.’’ Unfortunately, Cuban geology has been an inadequately known

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FIGURE 4. Cuba generalized geologic map. part of Caribbean geology. I hope this book helps improve knowledge of Cuban geology and will stimulate further work by both younger and older workers. The work done by Gulf Oil Corporation (Gulf ) in the early 1950s has never been published in its entirety. This publication an attempt to present it in the framework of Cuban geological studies done since and new general geological concepts. It must be stressed that the only way to properly describe this work is by defining and using the original stratigraphic nomenclature. Unfortunately, many of the names used have found their way into the official Cuban nomenclature, commonly with a different meaning than the original intent. Therefore, in this book, when a name used by Gulf is used in its original meaning, an asterisk follows (Santa Teresa*), thus differentiating it from any other usage. This in no way suggests changes to the present nomenclature. This book is divided into two sections. The first section, Overview, is printed herein and presents a broad description of Cuba’s geology and provides an interpretation of the geological events leading to the for-

mation of the island. The second section, Data, is on the accompanying CD-ROM in the back of this publication and provides a detailed description of Cuban stratigraphy, geophysics, and structures. Because hydrocarbons have been a significant driver for much of the study of Cuban geology, Chapter 6 in this publication entitled Hydrocarbons, gives a historical overview of work on petroleum occurrences.

POLITICAL SUBDIVISIONS Before 1976, Cuba was subdivided into seven provinces (Figure 1). In 1976, the island was subdivided into 14 provinces plus a district for the city of La Habana (Figure 2). The change postdates the acquisition of much of the precise information in this publication. To avoid errors converting from the old to the new provinces, the pre-1976 provincial nomenclature is used here. It should be noted that the Isla de Pinos is now Isla de la Juventud. The province of Matanzas has been

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FIGURE 5. Cuba generalized structure.

FIGURE 6. Cuba generalized cross sections.

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FIGURE 7. Cuba’s geologic provinces. extended to the south coast and includes part of the old Las Villas (Santa Clara) province. The remaining part of the old Las Villas province has been approximately subdivided into the Villa Clara, Cienfuegos,

FIGURE 8. Lithologic symbols used in sections.

and Sancti Spiritus provinces. The ‘‘Camaguey’’ province remains, but the boundaries have been changed; its western portion has been named ‘‘Ciego de Avila,’’ and its eastern part has been named ‘‘Las Tunas.’’ The

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FIGURE 9. Sedimentary terranes generalized geologic map.

old Oriente Province has been approximately subdivided into Holguin, Granma, Santiago de Cuba, and Guantanamo provinces. Pinar del Rio and La Habana have remained essentially unchanged except that the boundary between the two has moved some 30 km (18 mi) westward.

REGIONAL SETTING Cuba is the largest of the Caribbean islands and has an arclike shape, concave to the south (Figure 3). This shape has tempted some authors to call Cuba an ‘‘island arc.’’ The truth is much more complex. The

FIGURE 10. Eastern Cuba: sedimentary terranes generalized geologic map.

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FIGURE 11. North-central terrane sections. See Figure 8 for definitions of lithologic symbols. broad and deep Straits of Florida separate Cuba from Florida, and the narrow, and relatively shallow, Nicholas and Old Bahamas channels separate Cuba from the Bahamas. To the northwest, Cuba adjoins the Gulf of Mexico and is separated from the Yucatan Platform by the narrow but deep Yucatan Channel. To the south, the Yucatan Basin appears to be enclosed between Cuba to the north and the Cayman Ridge, which is the westward continuation of the Sierra Madre in the southern Oriente province. Cuba, the Cayman Basin, and the Cayman Ridge appear to constitute a physiographic province between the stable margin of the North American craton and the highly mobile Caribbean Basin. This province is separated from the Chortis-Nicaraguan rise block, including Jamaica and Hispaniola, by the east – west pull-apart basin of the Cayman trough, whose spreading center has been recording the eastward migration of the Caribbean plate since the late Eocene.

Over most of its length, the northern coast of Cuba is the dividing line between stable conditions (at least since the Middle Jurassic) to the north and west and very complex ones to the south. Figure 4 shows a generalized geologic map of Cuba. Although it is geologically deformed, the part of the northern coast of Cuba extending from eastern Matanzas to western Oriente belongs to the Florida-Bahamas carbonatebank province. To the south, in part under an upper Eocene or younger cover, is a relatively narrow belt, 45 –160 km (28–99 mi) wide, of intensely folded and faulted Middle Jurassic to middle Eocene rocks consisting, from north to south, of: 

the north-central sedimentary terranes, characterized by very thick platform carbonates and evaporites on the north and a relatively thin section of platform to pelagic carbonates and cherts on the south

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FIGURE 12. Western Cuba: southwestern terrane generalized geologic map. 



the ophiolitic basic igneous-volcanic (called igneous-volcanic because of being a mixture of intrusive and volcanic rocks with a general predominance of volcanic rocks) terranes, with ultrabasic intrusive rocks, many types and great thicknesses of basic, basaltic to andesitic volcanic rocks, volcanic-derived sediments, and granodioritic intrusives the southwestern sedimentary terranes, with primarily thin stratigraphic sections of platform to pelagic carbonates and cherts but locally with great thicknesses of older, continental-derived sandstones and shales showing various degrees of metamorphism

The most striking feature about the geology of the island is the great disparity between the ophiolitevolcanic sequence of the basic igneous-volcanic terranes and the sedimentary sequences of the northcentral and southwestern sedimentary terranes. Except for a few notable cases, essentially no relationship exists between these sedimentary and igneous terranes. There has been much argument about how the terranes

came into contact and became structurally mixed, but it is generally accepted today that the ophiolitevolcanic sequence is totally allochthonous. Figure 5 shows a map of Cuba’s major structural features and terrane distribution, and Figure 6 shows, in cross section, the structural relations between the various terranes. Nearly all major structural features formed after the early Maastrichtian and prior to the late Eocene. Quiet, continuous uplift has predominated in Cuba since the late Eocene. The island rose almost entirely above sea level during the Miocene and, except in the Escambray and the Sierra Maestra, Cuba today has a generally low elevation, although many areas have rugged topography. Cuba has had no volcanism since the middle Eocene and, with the exception of southern Oriente, has been seismically inactive in historical times. Despite its general low elevation, Cuba is an example of a Cretaceous – Paleogene Alpine orogenic feature in which thrust sheets moved northward over the craton. The ophiolites and volcanics are essentially unmetamorphosed, which is uncommon for an

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FIGURE 13. Southwestern terrane sections: Guaniguanico See Figure 8 for definitions of lithologic symbols. Alpine orogenic feature. In the northern Caribbean (with the possible exception of southeastern Belize), only in Cuba are shelfal deposits juxtaposed against ophiolites and deep-water volcanics and clastics. The other Greater Antilles Islands show intense deformation, but any former relationship to a continent is missing or has been obscured by strong transcurrent motion. The northern Venezuela Caribbean Mountains and their borderlands are structurally and timewise, but not stratigraphically, a mirror image of Cuba. This is the only other place in the Caribbean where thrust sheets of ophiolites, volcanics, and sediments moved over a craton (in this case, southward) during the early to middle Eocene. The associated metamorphism is much more extensive and intensive than in Cuba. Between these two orogenic belts with opposing vergence are the essentially undisturbed Late Cretaceous to Holocene Colombian and Venezuelan basins.

These basins are limited on the north and south by the trenches of the Muertos trough and the southern Caribbean (Curazao Ridge) deformed belt. The trenches, related to, respectively, north- and south-dipping subduction zones, are essentially inactive today. Separating Cuba from the Yucatan Basin is the Camaguey Trench, a northeast-dipping, apparently inactive trench under the Jardines de la Reina Cays. Although Cuba is now part of the North American continent, it is a remnant of a Cretaceous to early Tertiary orogenic belt that has been preserved because of the local configurations of the North American and Caribbean plates. As a consequence, Cuba exposes sequences of Upper Jurassic and Cretaceous nonvolcanic pelagic sediments that are rare, if not unique, in the Caribbean as well as in North, Central, and South America. However, Cuba has facies and faunal similarities with equivalent strata of the Tethys region, specifically the Alps and Italian Apennines.

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FIGURE 14. Southwestern terrane sections: Guaniguanico. See Figure 8 for definitions of lithologic symbols. Similarities and differences exist between the Jurassic–Cretaceous sedimentary sections of Cuba and other areas in the region. Nannoconus biomicrites containing aptychi, identical with the Neocomian of Cuba (and the Alps), are present in southern Belize, south of the Maya Mountains (Flores, 1952; Schafhauser et al., 2003); in Mexico, in the Lower Cretaceous of the Sierra Madre Oriental; and in the coreholes of Deep Sea Drilling Project Leg 77 in the southeastern Gulf of Mexico (this type of Cretaceous sediment is widespread in the deep Atlantic Ocean). In the Maya Block of the Yucatan Peninsula (and northern Belize, north and west of the Maya Mountains), all the reported carbonates belong to the Cretaceous Coban and Campur formations. They are similar to the bank carbonates of the Bahamas Platform and, therefore, are similar to the bank carbonates of north-central Cuba. The Coban Formation

grades northward into a thick evaporite section, which overlies the dominantly red clastics of the Todos los Santos Formation, that has been compared to the San Cayetano Formation of Cuba’s Pinar del Rio. Carbonates exist in the highly deformed Motagua fault zone, in central Guatemala, but similarity to carbonates found in Cuba is uncertain. The clastic El Plan Formation in the Chortis block of Central America in Honduras has been compared to the San Cayetano Formation. It shows lithologic and paleoenvironmental similarities. However, its Triassic to Middle Jurassic age, although somewhat in doubt, makes it older than the San Cayetano. El Plan Formation is a very controversial unit because all the contacts with other units are tectonic. Present in much of Central America is a Cretaceous carbonate section unlike the Cuban carbonates of the same age. It consists of Neocomian to Cenomanian, mostly shallow-water Yojoa Group limestone underlain

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FIGURE 15. Southwestern terrane sections: metamorphics. See Figure 8 for definitions of lithologic symbols. by Upper Jurassic to Lower Cretaceous clastics of the Honduras Group and overlain by the Upper Cretaceous Valle de los Angeles Group that consists mostly of red beds. Similar to the northeastern Cuban evaporites are Upper Jurassic(?) to Lower Cretaceous Maraval evaporites in the Paria Peninsula and Gulf of Paria, in the southern Caribbean between Venezuela and Trinidad. The metamorphosed clastics and marbles of the Jurassic to Lower Cretaceous Caracas series in northern Venezuela have some similarities to Cuba’s southern metamorphic massifs. In addition, the thick section of Upper Jurassic clastics of the Cosina Group (overlain by fossiliferous Neocomian carbonates of the Kesima, Palare, Moina, and Yaruma formations) in the Guajira Peninsula have similarities to the San Cayetano of Cuba’s Pinar del Rio. Some similarity exists between the Orbitolina-bearing reef carbonates of Cuba, Venezuela’s Lower Cretaceous Cogollo Group

and Cantil Formation, and contemporaneous facies of the Florida-Bahamas Platform. Close similarities exist between the Mesozoic igneous intrusive and associated volcanic rocks of Cuba and those of the Caribbean. Ophiolites are common throughout the Caribbean and extend from the Motagua fault zone, between the Maya and Chortis block, to Puerto Rico. They also form the floor of the Cayman Trench. These rocks are also common along the northern coast of South America from Tobago to the Guajira Peninsula, although they are not as intensely serpentinized as in the northern Caribbean. Cuba’s outcrops of ultrabasic rocks are the most extensive in the region. Similarities exist between the Caribbean and the Cuban Upper Cretaceous volcanic and associated intrusive rocks. The Cuban Upper Cretaceous granodioritic intrusion has counterparts outcropping in Hispaniola, Jamaica, and Puerto Rico in the north (where

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FIGURE 16. Central Cuba: basic igneous-volcanic terrane generalized geologic map. the intrusive’s ages range into the early Tertiary) and in Aruba, the Venezuelan Antilles, and the Aves Ridge in the south. Volcanics containing a characteristic fauna of Acteonella, large rudists (Hippurites), and orbitoids are present in Cuba, Jamaica, Hispaniola, Puerto Rico, the Dutch West Indies, and northern Venezuela, suggesting a connection between the various parts of the volcanic province. Other than the Yucatan Basin, Cuba is probably the only place in the Caribbean with complete sections representative of the early Caribbean region after the separation of North and South America and before the formation of the present Caribbean plate in the Tertiary.

STRATIGRAPHIC AND STRUCTURAL HISTORY The geological history of Cuba is part of the history of the Caribbean and, consequently, the history of the relative motions between the North and South American continents. As a result, as a background for the history of Cuba, some of the salient features of Caribbean history are included here. A more indepth look at Caribbean geology is presented in Dengo and Case (1990). Details of the stratigraphy and structure of Cuba are given in the Data section of this book located on the CD-ROM in the back of this publication.

To assist in the understanding of Cuba’s geologic history, a number of simplified geologic maps (locations shown on Figure 7) and accompanying stratigraphic sections will be presented. Triangles on the maps show the location of the stratigraphic sections, and Figure 8 shows the lithologic symbols used in the sections. Limited stratigraphic names are shown in the columnar sections for easy reference to the Data section of this publication. Stratigraphic unit names followed by an asterisk (i.e., Capitolio*) were originally named by Gulf’s geologists and might, or might not, be used today in the same context. Central and western Cuba are the only areas where the exposures of sedimentary terranes show sufficient facies relationships to permit meaningful, paleogeographic reconstructions of the early stages of the opening of the Caribbean. Central and eastern Cuba better represent the paleogeography of the rims of the later volcanic Caribbean plate. In this publication, the term ‘‘belt’’ is used. A belt in Cuba was originally defined by G. Pardo in 1953 and later published (Pardo, 1975, p. 561) as follows: ‘‘The central part of Cuba can be divided into a series of narrow linear and roughly parallel belts that extend along the north-central part of the island in a northwest–southeast direction. Each one of these is

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FIGURE 17. Central Cuba: basic igneous-volcanic terrane sections. See Figure 8 for definition of lithologic symbols. characterized by a diagnostic stratigraphy and structural style. These belts. . .’’ The definition of ‘‘belt’’ as applied in Cuba is discussed in detail in the Data section of this publication under Chapter 1, The Belt Nomenclature Problem. The use of belt was extended to western Cuba by Truitt (1956a, b) and, later, by other authors. It is still used in the Cuban literature. Belts are discreet, separate stratigraphic features, structurally brought into contact, and superimposed. The fundamental structural-stratigraphic model proposed here for Cuba is that of an Alpine orogeny along the continental margin of North America. It consists of shelfal carbonates paired with deep-water sediments, volcanics, and ophiolites thrust northward toward the craton. The model assumes the involvement of plate-tectonic processes and includes a proposal for Cuba (and other, geologically similar, areas) of a mechanism explaining the obduction of oceanic

crust over continental margins. Superimposed on this basic structure are other structural elements such as possible rifting and wrenching, which have contributed to confusion about, for example, the origin and mode of emplacement of the ophiolites. Walter Bu ¨ cher (1954, personal communication), Hatten et al. (1958), Rigassi-Studer (1963), Hatten (1967), Meyerhoff et al. (1969), Knipper and Cabrera (1974), Iturralde-Vinent (1977, 1981, 1996), Pszczo´lkowski (1999), Cobiella-Reguera (2005), and others have accepted variations on an Alpine orogenic model, but the nature and degree of acceptance varies. Meyerhoff et al. (1969) rejected the involvement of plate tectonics. Hess (1938) once used Cuba as the type symmetrical ‘‘Tectogene’’ (he changed his interpretation in later years). Flint et al. (1948) interpreted some of the major thrusting as being directed from north to south. Ducloz and Vuagnat (1962) postulated that many of the structures of central Cuba were caused

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FIGURE 18. Eastern-central Cuba: basic igneous-volcanic terrane sections. See Figure 8 for definition of lithologic symbols.

by deep-seated wrench faulting without major overthrusting and denied the existence of windows and klippen. Interpretations from the era of the former Soviet Union and Cuban cooperation are divided between thin-skinned and basement tectonics. It should be mentioned that Bohor and Seitz (1990) suggested that Cuba’s complex geology was caused by a meteorite impact in the Isla de la Juventud vicinity. This suggestion was not seriously followed, but mounting evidence shows that the Chicxulub K-T boundary meteorite impact had some effect on Cuba (see Officer et al., 1992). Pszczo´lkowski (1986b, 1999) proposed that the Cacarajicara Formation (and its correlative, the Amaro) was caused by such an event. Mounting evidence shows that the detritals of the Cacarajicara, Pen ˜alver, and the Amaro formations were caused by the Chicxulub tidal wave (Takayama et al., 2000; Kiyokawa et al., 2002), but carbonate turbidite deposits are

very common through the entire Cuban Cretaceous and lower–middle Eocene. The Lutgarta Formation contains many turbidites, interbedded with biomicrites and radiolarian cherts, which accumulated from the Santonian through the Maastrichtian. Furthermore, the most impressive carbonate breccia, the Sagua* Formation, reaches unquestionably into the lower to middle Eocene.

Restoration of Cuban Geology Structural complexities have shuffled the various components of Cuban stratigraphy. The present relative position of the outcrops is quite different from their position at the time of deposition or formation. Any palynspastic restoration will depend, therefore, on the assumed direction of thrusting. In this publication, all the major displacements are considered as having been from south-southwest to north-northeast.

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FIGURE 19. Western Cuba: basic igneous-volcanics terrane generalized geologic map.

North-Central Sedimentary Terranes Figures 9 and 10 are maps of central and eastern Cuba showing the distribution of the sedimentary belts separated by folded and faulted major thrusts. They also show the southwestern sedimentary terranes, Escambray and Asuncion, as windows through the basic igneous-volcanic terranes. This is the conventional interpretation and was Gulf’s interpretation in the late 1950s. It is also the interpretation of Hatten et al. (1958), Meyerhoff and Hatten (1968), Pardo (1975), and Hatten et al. (1988). This reconstruction is supported by: the presence of Jaguita* and Ronda* unmetamorphosed carbonate outcrops, along the Tuinicu fault, south of the basic igneous-volcanic terranes; the total lack of volcanic and ultrabasic components associated with the sedimentary terranes; and the fact that the basic igneousvolcanic terranes completely surround (in fault contact) the Escambray and Asuncion massifs. Figure 11 shows, from north to south, the thick Jurassic and Cretaceous carbonate and evaporite bank sections of the Punta Alegre* (PA) and Yaguajay* (Y)

belts, followed by the transitional Jatibonico* (J) belt and the Las Villas* belt. The type locality of the Las Villas* Belt at Quemado de Guines (QG) exposes a relatively thick section of Upper Jurassic bank carbonates of the Trocha* Group, which grade into the uppermost Jurassic deep-water limestones of the Caguaguas* Formation. The Jurassic is overlain by Lower Cretaceous, thin, deep-water, nannoplankton carbonates of the Capitolio* Formation. The Upper Cretaceous is mostly pelagic and distal carbonate bank turbidites, with radiolarian cherts, of the Calabazar* and Carmita* formations. Of note are the carbonate conglomerates of the Sabanilla* Formation, definitely derived from the south. The Upper Cretaceous is very thin and in places not represented by sediments. To the south, the Placetas* (P) and Cifuentes* belts, representing the higher thrusts, do not show any appreciable thickness of Jurassic sediments. In the southernmost Cifuentes* belt of Las Villas province at La Rana (LR), Jarahueca, and Rancho Veloz, the pelagic limestones of the Lower Cretaceous Ronda* Formation and the Jobosi* conglomerate rest on weathered,

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FIGURE 20. Northern Cuba: basic igneous-volcanic terrane generalized geologic map. strongly deformed, and allochthonous granodioritic basement. This basement must have formed a paleoridge (Meyerhoff’s ‘‘Median Welt’’) called here ‘‘La Rana’’; its original location is presently unknown. In the Sierra de Camajan window of the Camaguey province, the Lower Cretaceous Veloz (Ronda*) Formation rests upon the Tithonian Nueva Maria Formation that interfingers with tholeitic basalts. Present in the Cifuentes* belt is a widespread quartz-muscovite sandy limestone of Aptian–Albian age, the Constancia* Formation. The presence of abundant muscovite is surprising because the basement exposures are poor in micas. In the Yaguajay*, Sagua*, Jatibonico*, and Las Villas* belts, varied thicknesses of basic igneous detritus of the lower–middle Eocene Vega* Formation are invariably present underlying the Rosas* orogenic megabreccia. Basic igneous detrital clasts are present in the south in the Maastrichtian Miguel* Formation, as well as in the Rodrigo*, indicating that the basic igneousvolcanic terrane began to move in the Maastrichtian,

with deformation culminating in the early middle Eocene.

Southwestern Sedimentary Terranes The southwestern sedimentary terranes are characterized by the presence of a thick section of continentally derived clastics of mostly Middle Jurassic age. The Upper Jurassic and Cretaceous part of the section is very similar to the Las Villas* to Cifuentes* belts of the north-central sedimentary terranes. With one notable exception, the Cretaceous carbonate bank facies is absent. The southwestern sedimentary terranes show various degrees of metamorphism, principally in the Isla de la Juventud and the Escambray massifs. Figure 12 is a geologic map of western Cuba, including the Isla de la Juventud. Here, the exposures of Jurassic to middle Eocene sedimentary rocks form a group of low-elevation hills called the Sierra de Guaniguanico. In contrast with the tightly faulted and imbricated stack of south-dipping plates of central Cuba, the belts are less intensely tectonized, north-dipping,

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FIGURE 21. Western and northern Cuba: basic igneous-volcanic terrane sections. See Figure 8 for definition of lithologic symbols.

superimposed thrust sheets. Each belt consists of a stack of several sheets showing great similarity to each other. The present order of the belts is reversed from their original position. The significance of the larger number of imbrications in the Sierra de Guaniguanico (±30) than in central Cuba (7) is not clear. The larger number may be partly, but not entirely, caused by the quality of exposure; perhaps the more numerous imbrications are a result of greater horizontal displacement. Figure 13 shows sections on the eastern part of the Sierra de Guaniguanico, with the belts in their assumed original position. The Sierra de los Organos belt (PG, SG), like the Las Villas* belt, exhibits a fairly thick Upper Jurassic section of shallow-water carbonates, the Mogotesforming Guasasa Formation. It is transitionally underlain by the Jagua as well as the San Cayetano continentally derived clastics of Middle to Late Jurassic

age. The thickness of the San Cayetano varies from possibly very thin to nonexistent in the north to possibly very thick (more than 10,000 ft [3000 m]) in the south. Simultaneously, in the southern Rosario belt (CP), the Guasasa grades into the thinner, deeper water, thin-bedded carbonate facies of the Artemisa Formation. These carbonates are similar to and partly coeval with the Caguaguas*, Capitolio*, and Ronda* formations of the Las Villas*, Placetas*, and Cifuentes* belts. Farther south, in the northern Rosario belt (N), the Artemisa overlies and partially interfingers with the tholeitic basalts of El Sabalo Formation. This situation is identical with the one found in Loma Camajan in the Camaguey province. The Cretaceous section is generally thin and accumulated in deep water. The highest thrust sheet of the Sierra de Guaniguanico, Guajaibon–Sierra Azul (GSA), is highly unusual and difficult to explain. It consists mostly of

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FIGURE 22. Eastern Cuba: basic igneous-volcanic terrane generalized geologic map. massive bank carbonates with a facies (and microfacies) identical with the carbonate banks of the Yaguajay* belt of north-central Cuba. Being the highest thrust sheet under the basic igneous-volcanic terranes suggests a position south of much deeper water facies and no connection to the Bahamas banks. These rocks may have been deposited over the westward continuation of the southern La Rana granodioritic ridge exposed in the southernmost sheets of the Cifuentes* belt. Figure 14 shows sections on the western part of the Sierra de Guaniguanico. They differ from the eastern sections in having a greater thickness of San Cayetano clastics-Loma del Muerto (LM), and Pizarras del Sur (PDS) by an indication that the Guasasa Formation carbonates at EPEP Pinar-1 might not have been underlain by thick San Cayetano clastics (total depth of the well was near seismic-refraction basement) and by considerable quartz-sand development in the Cretaceous of the Esperanza (E) belt. Although these sands might have come from the Yucatan (Pszczo´lkowski, 1999), they are consistent with the southern granodiorite high and might correlate with the Cifuentes* and Placetas* belts’ Constancia* Formation of Early Cretaceous age. The Santa Teresa* Formation cherts, characteristic of the Cifuentes* belt, are well represented in the southern Rosario (LM, LP) and La Esperanza (E) belts. Although the Cacarajicara detrital limestone represents a remarkable distal turbidite, it is similar to the Carmita*, Amaro*, Lutgarta*, and Sagua* of north-

central Cuba. These turbidites were deposited throughout the Cretaceous and the early–middle Eocene. In the Sierra de Guaniguanico, variable thicknesses of Paleocene to lower–middle Eocene Manacas (similar to Vega*) basic igneous-derived detrital rocks, overlain by the Vieja (similar to Rosas*) orogenic megabreccia, are present above most thrust slices. Figure 15 shows sections of the metamorphosed massifs of Escambray and Isla de la Juventud. Because of the structural complexities in both massifs, the indicated thicknesses are questionable. The slightly metamorphosed Cangre belt–Pino Solo (PS) unit on the southern border of the Sierra de Guaniguanico is also shown. The Isla de la Juventud and Escambray massifs, although not studied to the extent of other areas in Cuba, have sections dominated by Middle Jurassic clastics (La Llamagua, Loma la Gloria, Can ˜ada, Agua Santa) equivalent to the San Cayetano Formation. The Upper Jurassic–Lower Cretaceous carbonates (Sauco, Cobrito, Mayari, and Collantes) seem to have accumulated in deep water, akin to the Artemisa Formation. In both massifs, as well as in the Cangre belt, the metamorphism appears reversed. The upper units are more metamorphosed than the core of the structures. For example, the upper Pino Solo unit has a higher metamorphic grade than the lower Mestanza unit. The age of metamorphism of the Cangre belt is Paleocene–early Eocene (Pszczo´lkowski, 1985). It is also very significant that the median radiometric

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FIGURE 23. Eastern Cuba: basic igneous-volcanic terrane sections. See Figure 8 for definition of lithologic symbols. age of metamorphism in Escambray and Isla de la Juventud is 66 m.y. or Paleocene (Iturralde-Vinent, 1996). This, together with the sedimentary evidence of the timing of thrusting, suggests that the reverse metamorphism was caused by the slab of basic igneousvolcanic terranes riding over the sedimentary terranes and not by the island arc thermal activity.

Basic Igneous-Volcanic Terranes Central Cuba Figure 16 is a map showing the distribution of the general types of igneous and volcanic rocks (including volcaniclastic) in central Cuba. Generally speaking, the basic igneous-volcanic terranes occur in a complexly folded and faulted synclinorium, which is separated from the underlying sedimentary terranes by the Domingo* fault. Above the fault and at the base of the volcanic section are various-sized bodies of

ultrabasics (serpentine, gabbro) to the north and metamorphosed ultrabasics (amphibolite) to the south. Highly sheared serpentine forms the base of the section and contains large blocks of exotic metamorphics. The trough of the synclinorium consists of oceanic volcanics overlain by arc volcanics and associated sediments. Several granodiorite bodies intruded the volcanic section from the central to the southern parts of the synclinorium and extend from the Escambray massif to eastern Camaguey. Figures 17 and 18 are representative columnar sections of the basic igneous-volcanic terranes in central Cuba. It should be noted that the sections of Santa Clara (SC), Santo Domingo (SD), and Camajan (C) show the best and most complete exposures of probable oceanic crust (Domingo* belt) and, possibly, upper mantle. The most complete and least deformed volcanic (Cabaiguan* belt) sections are exposed on the north and south flanks of the Seibabo syncline

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FIGURE 24. Palynspastic base.

FIGURE 25. 163 Ma: Callovian. PC = Precambrian; PZ = Paleozoic.

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FIGURE 26. 144 Ma: early Tithonian.

(SNF, SSF), and they provide the best basis for interpreting the origin of the volcanic rocks. The Lower Cretaceous in the Seibabo syncline consists mostly of basalts and basic volcaniclastics. Part of the Cenomanian – Turonian section contains no volcanics. This section comprises the Gomez* and Huevero* dark-gray shale and black nodular limestones and the Cristobal* and Casanova* detrital, fine- to medium-grained limestones containing Upper Jurassic detrital oolites and other fragments. This volcanic-free section represents a period of volcanic quiescence following the formation of the new Upper Jurassic–Cretaceous oceanic basement and preceding the development of an Upper Cretaceous volcanic arc. Of the above units, the Gomez* Formation is the most characteristic and can be recognized in many localities. It must be noted that in the Las Villas province, most of the exposed volcanics are Early Cretaceous or older in age, whereas in Camaguey, they are middle to Late Cretaceous in age. Contrary to the interpretation of Iturralde-Vinent (1996) and others, volcanism was active during the Maastrichtian as shown by outcrops of the Las Villas province (Hilario*, Cotorro*, and Carlota*) (see Data section on the CD-ROM in the back of this publica-

tion). Piggyback basins characterize the Paleocene and lower–middle Eocene. They contain volcanic-derived sediments, marls, and limestones. The Taguasco* Formation, consisting of conglomerates containing large spherical granite boulders, and its equivalents are found at the base of the section.

Northern and Western Cuba Figures 19 and 20 are maps showing the distribution of the basic igneous-volcanic terranes in western and northern Cuba. Here, the Sierra de Guaniguanico occupies a structural position equivalent to the Escambray massif; it is a window of sediments cut by the Pinar fault to the south. An outlier of unmetamorphosed arc volcanics exists on the north of the Isla de la Juventud, the Teneme Formation. The most complete sections of basic intrusive and volcanic rocks occur north of the Sierra de Guaniguanico in the Bahia Honda (BH) and Felicidades (F) belts. Figure 21 shows several sections of this terrane. The most complete section of oceanic crust is found at the base of the Bahia Honda (BH) belt and is very similar to the section present in central Cuba. The Lower Cretaceous is not as well developed as in central Cuba and

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FIGURE 27. 132 Ma: Valanginian.

has not been studied in detail, but the middle to Upper Cretaceous Quio ˜ nes Formation in the Felicidades (F) belt shows some affinities with the Gomez* and Huevero* formations of central Cuba. However, Upper Cretaceous, Paleocene, and lower–middle Eocene outcrops are widespread and, being near Havana, have been studied in detail for many years. These lower Tertiary deposits form well-developed piggyback basins that were transported northward by the advancing ophiolite sheet, with no indication of nearby volcanic activity.

Eastern Cuba Figure 22 is a map of eastern Cuba showing the various provinces. Eastern Cuba is characterized by a strongly tectonized, steeply southward-dipping, basic igneous-volcanic section (Kozary, 1968, referred to it as the collapsed Aura trench); a nearly horizontal, allochthonous, ultrabasic sheet overriding the volcanics in the Mayari and Baracoa massifs; the metamorphosed volcanics of the El Purial massif; and a thick lower– middle Eocene section of the El Cobre arc volcanics. Figure 23 shows several stratigraphic sections through eastern Cuba. The thicknesses are questionable in

most areas, but especially in northern Oriente (NO) and southeastern Oriente Purial massif (PM). However, there is no question that the lower – middle Eocene Cobre Formation is very thick. It contains the only lower Tertiary volcanic rocks in Cuba. The Purial massif is the only place in Cuba where the volcanic section exhibits regional metamorphism; these volcanic rocks are under a nearly horizontal imbrication of an ultrabasic sheet. A small window of slightly metamorphosed southwestern terranes sediments is present at La Asuncion. Figure 24 is a palynspastic base showing the approximate relative positions of the different belts at the time of their deposition. It also shows the equivalence of the belts between the different areas of Cuba. The Domingo-Cabaiguan belt could have originated farther to the southwest in the middle Cretaceous.

HISTORY OF CUBA The summary here of the geological history of Cuba has been strongly influenced by the geology of central Cuba. However, the timing of the events was not isochronous along the whole length of the orogen.

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FIGURE 28. 110 Ma: Aptian. Paleogeographic maps (Figures 25 – 34) illustrate the possible past distribution of the most characteristic stratigraphic units. These maps are on a continental drift base modified from the Ocean Drilling Stratigraphic Network (ODSN) created in 2005 by the University of Bremen, with Florida occupying a fixed position. In all maps, Cuba is shown in its present position relative to Florida, although different parts of the island came from various places. The first map of the sequence, 163 Ma (Callovian), shows the position of the African and South American cratons. In these maps, ‘‘autochthonous nappes,’’ ‘‘allochthonous nappes,’’ and ‘‘subduction’’ will be used to describe, respectively, the thrusting toward the continent of the sediments, the basic igneous-volcanic rocks, and the subduction. Supported by observations in Cuba and elsewhere, these maps (as well as cross sections discussed later) show subduction as the main cause of the uplift of a convergent continental margin or ocean floor, whereas the nappes are the result of sedimentary or volcanic cover sliding away, under the force of gravity, from the area uplifted by subduction.

Burke (1988), Pindell and Barrett (1990), IturraldeVinent (1996), Cobiella-Reguera (2005), Garcı´a-Casco et al. (2006), Giunta et al. (2006), and Pindell et al. (2006), have interpreted the Cretaceous Cuban subduction as northeast dipping and reversing polarity to the southwest during the Upper Cretaceous. Cuba’s geology suggests that the subduction was continuously north dipping, and this concept is discussed in more detail below. The paleogeographic history presented here is in general agreement with that of Pszczo´lkowski (1999). Differences are, for example, the position of the Guajaibon–Sierra Azul belt, the origin of the middle Cretaceous quartzose clastics, and the dip of the subduction zone.

Early(?)–Middle Jurassic Very little is known about the pre-Late Jurassic history of the island except that the lower part of the San Cayetano clastics might be Lower Jurassic (163 Ma; see Figure 25). The San Cayetano must have been deposited over an initially rifting basement that probably included fragments of continental crust as well as

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FIGURE 29. 94 Ma: Cenomanian.

basaltic flows. This is supported by the pre-Neocomian granodioritic klippen of La Rana, Tre´s Guanos, and Rancho Veloz and the occurrences of the El Sabalo and Nueva Maria tholeitic basalts underlying the sedimentary section of the northern Rosario belt and Cifuentes* belt of the Sierra de Camajan. It can also be assumed that, prior to the deposition of the Upper Jurassic rocks, a large area of basement was exposed to the northwest, extending from Florida’s Sarasota arch to the Maya Mountains. The nature of this basement is generally unknown, but it must have been of granitic to granodioritic composition as indicated by the arkosic nature of the San Cayetano Formation. In south Florida, several wells have penetrated an undifferentiated Jurassic–Triassic volcanic section and Paleozoic granite. The basement must also have included Paleozoic sediments known to outcrop in the Maya Mountains, present as fragments in San Cayetano conglomerates, and, perhaps, as exotics in the Cayo Coco Formation. The bulk of the San Cayetano Formation accumulated south of this basement high. The San Cayetano clastics could have originated from the Gulf of Mexico, as well as nearby South

America. As already mentioned, some studies indicate that the southwestern part of the San Cayetano originated from the southwest, and the northeastern part originated from the northeast. Structural complexity makes source direction hard to evaluate. Toward the northeast, pre-Upper Jurassic sediments have not been observed in situ, but the Cunagua salt suggests the presence of an evaporite basin correlating with the Louann Salt and Maraval evaporites and, possibly, as suggested by the San Adrian Formation, interfingering with the San Cayetano. As rifting continued, new oceanic crust formed with outpouring of basalts (El Sabalo) and serpentinization of the upper mantle.

Tithonian In the Tithonian (144 Ma; see Figure 26) section, sediments vary from the shallow-water, carbonate, and evaporite deposits of Wood River, Punta Alegre*, and Guani* in the north, toward Florida and the Bahamas, to shallow-water, normal marine limestones of the Trocha* Group to the south in the Las Villas* belt. Toward Pinar del Rio, thick, massive, shallow-water

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FIGURE 30. 80 Ma: Santonian. limestone of the Guasasa Formation accumulated over a northward-thinning wedge of San Cayetano, Jagua, and possibly, basement. Farther south, the thinbedded limestones of Cobrito, Sauco, and Isla de la Juventud marbles were deposited over the lower Oxfordian thin, quartzose sandstones of La Llamagua, Loma la Gloria, and Agua Santa formations. The outpouring of basalt continued forming the slightly younger Nueva Maria Formation in the southern Loma Camajan. Farther south, rifting produced ultrabasic oceanic crust.

Neocomian Shallow-water platform carbonates, with some evaporites, continued to accumulate in the north (coastal area, Yaguajay* belt). Elsewhere in central and western Cuba (Las Villas*, southern Rosario belts), the water was markedly deeper as indicated by the deposition of the Capitolio* and Artemisa formations containing abundant nannoplankton (commonly rock forming) and other pelagic forms. Some tectonic activity extended into the Neocomian (132 Ma; see Figure 27), possibly associated with

the rifting, and uplifted blocks south of the Yaguajay* belt. The result was denudation of previously deposited sediments as indicated by northward shedding of carbonate clastics (Sabanilla* Formation), a southward increase in basement exposures (La Rana, Tre´s Guanos, Rancho Veloz), and deposition of the Jobosi* arkosic conglomerate. This basement could have been derived from a continental block, here named the La Rana block (after the best exposures) and similar to the Maya or Chortis blocks, that was overridden by later nappes. In central Cuba, the Upper Jurassic and Neocomian beds were only partially eroded. In western Cuba, shallow-bank carbonates, similar to those of the Vinas* Group, accumulated atop the La Rana granodiorite horst and formed the Guajaibon – Sierra Azul belt. South of the La Rana basement horst, deep-water limestones of the Mayari, Collantes, and Cobrito formations were deposited and preserved. Farther south, rifting continued, accompanied by outpouring of tholeites and other basic to ultrabasic material forming a layered oceanic basement consisting of peridotite, gabbro, sheeted dikes, pillow basalts (old volcanics of the Domingo* sequence), and

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FIGURE 31. 67 Ma: Maastrichtian. associated sediments. Although some genetic relationship exists between the Domingo* sequence and the El Sabalo – Nueva Maria lithologies, these belong to two entirely different provinces. El Sabalo and the Nueva Maria formations, like the granodiorites, belong to the autochthonous nappes and were at the continental margin, whereas the Domingo* sequence forms the base of the allochthonous nappe and is entirely oceanic.

Barremian During the Barremian, deposition of platform carbonates continued in the north, grading from shallowwater algal types, with fewer evaporites, to breccias. South, west, and possibly east of the Bahamas Platform, deep-water sedimentation of pelagic (nannoplankton) carbonates continued. However, because of the late Neocomian tectonic activity, conglomerates, derived from the previously deposited limestones in the Las Villas* belt and from the exposed granitic basement in the Cifuentes* belt to the south, became common. No Barremian sediments were deposited in some of the southern areas. However, the basaltic to intermediate

flows possibly continued to accumulate over the southern part of the basic igneous basement.

Aptian During the Aptian (110 Ma; see Figure 28), deposition continued to be shallow-water marine along the north coast (Yaguajay* belt) with, farther to the north (Cayo Coco area) and as far as Oriente (Gibara area), some pelagic influence (Casablanca Group). Toward central and western Cuba, conditions continued to be pelagic. The pelagic and shallow-water conditions were separated by a conglomeratic breccia zone (Sagua la Chica* belt) representing a forereef facies, although reefs themselves are not common in outcrops. There was an influx of quartz- and mica-rich turbiditic detritus, possibly from the erosion of the previously formed basement high, which formed the La Esperanza, Polier, and Constancia* formations. A southern Guajaibon–Sierra Azul carbonate bank may have been deposited. Toward the south, the close of the Early Cretaceous was characterized by a great outpouring of basaltic flows (Matagua´* Formation) over rifted basement.

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FIGURE 32. 50 Ma: top lower Eocene.

This activity was accompanied toward the north and west (Cifuentes*, southern Rosario, northern Rosario, and La Esperanza belts) by abundant and extensive chert deposits (Calabazar*, Carmita*, and Santa Teresa* formations).

Albian–Cenomanian Except for the Yaguajay* belt along the north coast where platform carbonates accumulated, deep-water pelagic deposition continued during the Albian to Cenomanian (93 Ma; see Figure 29). In the south, volcanic activity contributed silica to the seawater, which led to the deposition of primary radiolarian cherts (Calabazar*, Carmita, and Santa Teresa) below the carbonate compensation depth. Whereas noncalcareous detritus was absent over most of the northern area, volcanic-derived clays became increasingly abundant toward the south (Santa Teresa* Formation). The Rana granodiorite high was still active, providing material for the Chaco Azul Formation. The position

of the Vin ˜as* type carbonates of the Guajaibon–Sierra Azul belt is problematic. To the north, as during the Aptian –Albian, the shallow carbonate banks continued to be separated from the pelagic, deep-water sediments to the south by a zone of carbonate-derived clastics, which shifted progressively southward; carbonate turbidites became increasingly abundant (Calabazar* and Mata* formations). In the Florida Straits, carbonate deposition did not keep up with subsidence as indicated by the increase in pelagic deposits, including chert (upper Casablanca Group). Toward the south, the volcanic activity that formed the lower Cabaiguan* sequence decreased markedly, and argillaceous, calcareous sedimentation became predominant, whereas conditions remained pelagic. The detrital limestones in the southernmost outcrops of the volcanic sequence (Cristobal* Formation) that contain abundant Upper Jurassic reworked carbonates (including oolites) indicate an unknown southern source, possibly the Yucatan Platform.

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FIGURE 33. 40 Ma: base upper Eocene.

With the exception of the thick carbonate banks, the Cenomanian sediments are mostly uniformly thin.

Turonian–Campanian Turonian and Coniacian sediments are not common across most of the nonvolcanic area (80 Ma; see Figure 30). They are present to the north in the Cayo Coco area, to the south in the Seibabo area in central Cuba, and in a few units of the southern and northern Rosario belts in western Cuba. The strata above and below the missing interval all have deep-water characteristics, and no evidence of subaerial erosion exists to explain the lack of the Turonian and Coniacian sediments across such a large area. Either there was no deposition, or the section was eroded because of changes in current patterns or submarine slides. Local erosion is unlikely because a hiatus of the same age has been found in many of the holes drilled by the DSDP in the southern Gulf of Mexico and the western Atlantic. Toward the north, in the platform

to deep water province, whatever sediments remain show that sedimentation continued under pelagic conditions and was essentially calcareous, with subordinate cherts. Toward the south in the basic igneous-volcanic province, conditions were also dominantly pelagic. Sedimentation was accompanied by a renewal of volcanism, with an outpouring of flows and other ejecta of a more rhyolitic composition (Pastora* Group). Evidence of subaerial volcanism (such as glass bombs and ash beds) exists. Shallow-water reefs with rudists, corals, and large foraminifera are commonly associated with the volcanics and volcaniclastics. This was the period of major arc volcanism associated with subduction. It was also the time of intrusion of the Manicaragua granodiorite into the central Cuba volcanics.

Campanian–Maastrichtian After the period of the disconformity, pelagic conditions characterized the platform to deep-water province, which received massive, dominantly carbonate

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FIGURE 34. Present.

turbidite flows from the north (Lutgarda* Formation) and from the south (Amaro* and Cacarajı´cara formations) (67 Ma; see Figure 31). Over the basic igneousvolcanic province, local provenance resulted in an abundance of fragmental rocks; that is, limestones toward the north (Pen ˜alver Formation) and volcanics toward the south. In the south, sedimentation was accompanied during the Maastrichtian by an outpouring of late orogenic basaltic flows and flow breccias (the Maastrichtian age of these flows disagrees with the current interpretation of most Cuban geologists, including Iturralde-Vinent, 1996). Toward the north, along the present outer line of clays, deposition of coarse Maastrichtian limestone conglomerate (Mayajigua* Formation) graded into fine-grained pelagic rocks. The basic igneous-volcanic province began its initial northward movement as indicated by serpentine detritus in the turbidites, by basic intrusivederived clastics (Miguel Formation) associated with the Domingo* thrust, as well as by the presence of

large Maastrichtian thrust sheets of ultrabasics in Oriente. Thrusting (and metamorphism) of ultrabasics began in the Escambray, and thrust sheets began to stack into the former basin that is today represented by the Guaniguanico Mountains. Northward-dipping subduction to the south produced uplift of the convergent margins. The northward-moving thrust sheets or nappes formed as the result of the sedimentary or volcanic cover sliding away from the uplifted areas.

Paleocene (Danian) The Paleocene is very poorly represented in Cuba for reasons that are not entirely clear. Fossils this age have been found only in Cabaiguan* sequence rocks in Habana, Las Villas, and western Camaguey provinces, but the paucity of the Paleocene is probably not just a paleontological artifact. Strata above and below contain rich lower Eocene and Maastrichtian faunas, respectively. Where present, the Maastrichtian

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FIGURE 35. Obduction 1. See Figure 8 for definition of lithologic symbols.

was deposited in deep waters and so was the lower– middle Eocene flysch. No indication of subaerial erosion or unconformity exists.

Early to Middle Eocene The early to middle Eocene was characterized by intense orogenic activity (50 Ma; see Figure 32). Early in the Eocene, the large-scale low-angle thrust sheets, or gravity nappes, that first moved in the Maastrichtian began to move at a greater rate. The volcanic section, along with the oceanic basement, rode over the platform to deep water province, probably along the line separating the basic igneous-volcanic province from the platform to deep basin province. As thrusting proceeded, additional thrusts formed within the carbonate section in front of and north of the basic

igneous-volcanic front. As a result, the thrust sheets were generally arranged from older and more southerly sourced at the top of the stack to younger and more northerly sourced at the base. A large trough-shaped basin formed in front of the thrust sheets, deeper near the thrust front and shallower northward. Lower to middle Eocene flysch deposition in the trough began with sediments derived from limestones, such as the Sagua* and San Martin* formations, followed by an increase in volcanic and intrusive-derived detritus, such as the lower Vega* and lower Manacas (Pica Pica) formations, and finally, capped by the intrusive and volcanic-derived coarse conglomerates and wildflysch of the upper Vega* (Rosas*) and upper Manacas (Vieja) formations. In central Cuba, the rocks of the deep-water Vega* Formation became coarser grained through time. In

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FIGURE 36. Obduction 2. See Figure 8 for definition of lithologic symbols.

western Cuba, the fine-grained clastics and other pelagic sediments of the Manacas Formation changed abruptly to the coarse breccias of the Vieja Member. The breccia clasts reflect the lithology of the associated fault blocks. This suggests some subaerial erosion in central Cuba, whereas western Cuba was largely submarine. South of the front of the advancing volcanic and basic intrusive-rock thrust plate, a second series of basins developed parallel to the northern trough. Within these basins, which were carried piggyback by the thrust plate, lower Eocene igneous-derived sediments accumulated, but under quieter tectonic conditions (the Taguasco*, Bijabo*, Santa Clara*, Alkazar, Bacunayagua, Capdevila, and Universidad formations, for example). As the thrust sheets advanced, they overrode the lower to middle Eocene flysch, which had accumu-

lated in front of them, and the flysch served as a lubricating medium for further thrusting. The subduction responsible for the uplift driving the thrusting ceased progressively from west to east, and volcanic activity continued in Oriente until the middle Eocene. Along what appears to be a north-dipping subduction zone and south of the Jardines de la Reina Cays (Camaguey trench) is a filled trench, which is a remnant of an accretionary prism. This trench could be related to the exposures in Haiti’s southern peninsula and the Muertos Trench. In central and eastern Cuba, the thrust front advanced until the volcanic and basic intrusive rocks covered extensive areas of the massive shallow-water carbonates of the northern coast of the island (Yaguajay* belt, coastal and Gibara areas). After the front stopped advancing, compression from the south continued, tightly folding and then reverse faulting the

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FIGURE 37. Scotia Sea bathymetry. Modified after the National Oceanic and Atmospheric Administration Satellite and Information Service.

FIGURE 38. Scotia Sea structural interpretation. PZ = Paleozoic.

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FIGURE 39. Scotia Sea structural interpretation on bathymetry. Modified after the National Oceanic and Atmospheric Administration Satellite and Information Service. FZ = fault zone; PZ = Paleozoic. succession of thrust plates. The result was the late Eocene structures shown in Figure 33. As compression continued, the folds became sharper, and the faults

FIGURE 40. Caribbean topography.

began lateral motion, probably because the northward compression was not directed perpendicular to the front of the carbonate banks. It is possible

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FIGURE 41. Caribbean free air gravity. Modified after Sandwell and Smith (1997). that a deep-seated, crustal transcurrent fault was also involved. In western Cuba, the northward-moving stack of thrust sheets did not reach the buttress of the Bahamas Platform, and the nappes came to rest on the sea floor toward the southern Gulf of Mexico. As a result, they are less deformed than they are to the east. It is possible that a large number of the present-day high-angle faults, some with reverse thrusting (Seibabo syncline), formed during the last phase of the orogeny. The intense orogenic activity ceased toward the close of the middle Eocene or early late Eocene, and the uplifted, faulted, and folded orogenic complex was subsequently eroded and peneplained.

Late Eocene to Present Shallow-marine conditions prevailed during most of this time interval, and mostly limestones, marls, and shales accumulated, accompanied by some coarse clastic sediment (present; see Figure 34). There was very little tectonic activity. In the northern basins, a strong angular unconformity separates the upper Eocene strata from the older rocks. In the southern basins, sedimentation was essentially continuous from the Cretaceous through the Tertiary, with no major

unconformity. Some local basins may have formed as gentle deformation of the old orogenic belt occurred. This deformation consisted mostly of large-scale folds (Habana-Matanzas) and high-angle faults (Pinar). This type of deformation is still active today and is largely responsible for Cuba’s present physiography. Cuba is an example of subduction generating an orogenic belt. The subduction progressed from an oceanic environment through a region of relatively recent oceanic crust between North and South America and, finally, became inactive at the southern margin of the North American continent. The main difference relative to most of the well-known marginal orogenic belts is that the thrust sheets that accompanied the subduction rode onto and over a much depressed and fragmented continental margin (with fragments now in the Bahamas Basin, Gulf of Mexico, Yucatan) relatively far away from a fully continental craton. The orogeny was characterized by a scarcity of detrital sediments on its continental side and by the rapidity of the entire orogenic process that started during the Late Cretaceous and culminated within the early to middle Eocene. It also shows clearly that when the thrusting occurred, the continental margin was not contiguous with the subduction, but was separated from it by an arch, which mostly exposed

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FIGURE 42. Caribbean structural interpretation. PC = Precambrian; PZ = Paleozoic. See Figure 8 for definition of lithologic symbols.

granodioritic basement rocks. The Alps show similar geology. The northward displacement of the visible thrusting was on the order of several hundred kilometers.

CUBA’S CONTRIBUTION TO THE UNDERSTANDING OF OBDUCTION A great contribution of Cuba to our knowledge of orogeny is that it provides evidence that obduction must not be the converse of subduction. That is to say, the obduction in Cuba did not result from the pushing of oceanic crust over the top of a subducting plate. The evidence from Cuba indicates a different process, which could have much more general application than just in Cuba. This process was referred to above, will be explained further below, and is diagrammatically shown in Figures 35 and 36.

The Domingo* belt shows a characteristic cross section of oceanic crust (>4000 m; >13,100 ft), with serpentine at the base. The serpentine very probably formed during oceanic rifting when seawater came near, or in contact with, the upper mantle. As the serpentine became buried under layers of basalt and associated volcaniclastic, its low permeability did not allow the water to escape at a rate directly related to the weight of accumulating overburden. The water bore much of the overburden load, which generated near geostatic pore-fluid pressure. The resultant decrease in shear strength would have produced a definite low-velocity Moho discontinuity. The decrease in shear strength created unstable oceanic crust, similar to the overpressured shales at the base of normally compacted deltaic sedimentary sections. For Cuba, north-dipping subduction of oceanic crust under the newly rifted oceanic crust raised the newly formed oceanic crust. It broke up and, under

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FIGURE 43. Structural interpretation on topography. Modified after the National Oceanic and Atmospheric Administration Satellite and Information Service. PC = Precambrian; PZ = Paleozoic. See Figure 8 for definition of lithologic symbols.

the force of gravity, detached along the overpressured serpentine and slid downhill toward the foreland basin and away from the subduction zone. This Cuban scenario is supported by the presence of metamorphic exotics in the serpentine; by the absence or the relatively low-grade reverse metamorphism of the sediments underlying the serpentine; by the total lack of metamorphism of the volcanics overlying the oceanic crust; by the diapirism and evidence of flowage exhibited by many serpentine bodies and contained exotics; and by the definite evidence of stacked oceanic thrust sheets in the Santa Clara–Placetas area, as well as in the Mayari and Baracoa massifs in eastern Cuba. As the subduction of oceanic crust under oceanic crust migrated, the uplifted and now-detached allochthonous fragment of newly formed oceanic crust kept sliding northward away from the subduction zone until it overrode (was obducted over) the continental margin, capturing and dragging, in its base, fragments of that margin, and eventually riding over a bed of detritus derived from its own basic igneous rocks (the Vega and Vieja formations). This obducted, allochthonous sheet carried, piggyback, the arc volcanics and volcanoclastic basins. The continental margin deep-

water carbonates and cherts also became involved in the slide and were pushed in thrust sheets in front of the advancing oceanic crustal sheet. Away from its front edge, the warm slab of sliding oceanic crust caused reverse metamorphism (Maastrichtian –early Eocene) in the Trinidad and Isla de la Juventud massifs and Pinar del Rio’s Cangre belt. The granodiorite associated with the arc volcanism was intruded during the Late Cretaceous and, thus, preceded the metamorphism. The Cuba subduction was part of the Caribbean oceanic crust subduction extending from the Yucatan to the Saba Bank. A continuous series of oceanic crustal blocks became detached and began sliding northward from late Maastrichtian near Yucatan to early Eocene toward Hispaniola. To the west, the sliding was over the oceanic crust of the Yucatan oceanic basin (Pinar del Rio). In central Cuba, the sheet of oceanic crust slid (was obducted) onto the southward-projecting Florida-Bahamas continental margin. Exposed farther to the east, in Hispaniola and Puerto Rico, is the Caribbean oceanic crust subducted under the Atlantic oceanic crust (Haiti southern peninsula, Muertos Trench), where it is possible that the Caribbean oceanic crust

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FIGURE 44. 162 Ma: Callovian. A = Africa; FL = Florida; NA = North America; SA = South America. was also obducted by sliding over the Atlantic oceanic crust. Obduction appears to accompany subduction only in cases of subduction of oceanic crust under oceanic crust and, as in Cuba, northern Venezuela, and the Alpine ranges, on thinned continental margins adjacent to spreading the Caribbean- and Mediterraneantype oceans. In Cuba, the obducted sea floor is the sea floor that was originally on the upside of the subduction; therefore, the obduction moved in the same direction as the dip of the subduction. In other words, the evidence from Cuba indicates that the continental plate was not subducted under the oceanic plate. It is very possible that this Cuban obduction process may be the most common form of obduction.

CUBA’S CONTRIBUTION TO THE HISTORY OF THE CARIBBEAN North America began separating from Africa during the Triassic, approximately 200 Ma, and paleogeographic reconstructions prior to 150 Ma are uncertain. Pindell and Barrett (1990) present what may

be the tightest fit, but at the expense of moving parts of Mexico out of the way through the Mojave-Sonora megashear and rotating and sliding crustal blocks such as the Yucatan and southern Florida. Salvador and Green (1980) give an interesting reconstruction of the early stages of separation in the Late Triassic (200 Ma). They postulate that the Yucatan block was farther north in the Gulf of Mexico, but otherwise, Florida, the Bahamas, and Cuba were as they are today, except that the entire area was much closer to South America. This reconstruction has the advantages of being simple and based on regional geology and is adopted, in part, here. Also assumed here is that since the Triassic period, the South American continent has included the Cordillera Central and the Santa Marta massif in Colombia, and that the Bocono fault in Venezuela has been of minor importance. Many problems concerning the history of the Caribbean exist that the geology of Cuba cannot resolve. An example is accounting for the postulated 1100 km (683 mi) of left-lateral displacement of the Cayman rift and the introduction of the NicaraguaJamaica rise since the upper Eocene, although the relative positions of North and South America remained

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FIGURE 45. 144 Ma: early Tithonian. A = Africa; FL = Florida; NA = North America; SA = South America.

essentially unchanged during that time. It is almost impossible to locate a right-lateral displacement of the same magnitude (even with multiple smaller faults) along the north coast of Venezuela. Another example is whether the circum-Caribbean orogenies originated with a Great Arc (Pindell and Barrett, 1990), spreading from the Pacific Ocean, or whether there were multiple arcs. A third example is the polarity of the subduction. James (2006) proposed an in-situ origin based on similarities to areas such as the Scotia Sea and Banda arc. The gross morphological similarities between the Caribbean and the Scotia Sea are obvious. Both appear to be eastward oceanic incursions between two continental masses: North and South America, and South America and Antarctica. Both are limited to the east by an active volcanic arc resulting from westwarddipping oceanic – oceanic subduction, and in both cases, the western margins of the westward-drifting continents are bounded by eastward-dipping continental and oceanic subduction. In both cases, it appears as if the oceanic floor is moving eastward in relation to the continents.

Some important differences exist. The Scotia Sea shows a definite oceanic basement, with a presently active east-northeast-spreading axis, interrupted by several west-southwest transverse faults (Figures 37–39). This oceanic basement seems to be continuous with the Pacific, although separated by the Shackleton fracture zone. Each spreading strip between transforms seems to end in subduction, either under the South American or the Antarctic continent. The oceanic crust is being generated in situ and does not come from the Pacific. The major Caribbean basins (Yucatan, Colombian, and Venezuelan), however, do not have presently spreading oceanic crust; only one short, active, north– south-spreading axis exists in the center of the Cayman trough (Figures 40–43). These basins are not considered typically oceanic, and only weak magnetic anomalies indicate a spreading center in the Venezuelan Basin, which has remained inactive for the last 127 m.y. (since the Hauterivian). This is puzzling because the distance between North and South America increased continuously from the Triassic until the Campanian (80 Ma). In addition, in the Caribbean,

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FIGURE 46. 132 Ma: Valanginian. A = Africa; FL = Florida; NA = North America; SA = South America.

undisturbed Upper Cretaceous (Turonian) and younger pelagic sediments overlie older volcanics (such as basalts, dolerites, and tuffs). The South American continent south of the Cerros de la Ventana (correlated to the Africa’s Cape Mountains) is covered by a large expanse of Jurassic volcanics (Serie Tobifera), which forms the basement. Protruding out of this basement are the Paleozoic Falkland (Maldives) Islands. Precambrian rocks have been cored on the Falkland plateau. The Tierra del Fuego Andes and the Antarctica Peninsula have a Paleozoic core. The Scotia Sea appears, therefore, to have opened across a Paleozoic to Precambrian continental mass (Dalziel, 1974). Unlike the Scotia Sea, very confusing evidence of what happened at the end of the Paleozoic in the Caribbean area exists. The Ouachitas do not appear to be a simple continuation of the Appalachians. Drilling south of the Ouachitas shows thick, slightly metamorphosed(?), and relatively undisturbed Cambrian– Ordovician Ellenburger carbonates. No known volcanic or igneous equivalent exists, unless it runs under the Gulf of Mexico or farther south. The Andes of to-

day resulted from the superposition of orogenic deformation that started in the Paleozoic. The Cambrian of Colombia is characterized by Atlantic province trilobites and not Pacific. How the Appalachian orogenic belt (or the Hercynian Atlas) connected with Colombia is unknown, but it must have gone through the Caribbean region prior to the opening of the Caribbean. Fragmental outcrops of Precambrian to upper Paleozoic rocks are present in Mexico, from the Cabo de las Corrientes through Oaxaca, in the Maya Mountains, and in north-central Nicaragua (Dengo, 1975). In central Florida, drilling has penetrated Paleozoic granites and metamorphic rocks below a Triassic to Lower Jurassic volcanic complex. Allochthonous basement blocks in Cuba range in age from Precambrian to at least Late Jurassic. The evidence suggests that the early Caribbean basement also consisted of metamorphics and plutons reflecting the Appalachian or Hercynian orogeny. Perhaps the Scotia Sea is an analog of the early stage of the opening of the Caribbean. That would suggest that the Caribbean oceanic crust formed in situ and was not of Pacific origin. Assuming that this is true,

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FIGURE 47. 110 Ma: Aptian. A = Africa; FL = Florida; NA = North America; SA = South America. both the Scotia Sea and the Caribbean would have similar relations between spreading axis and oceanunder-continent subduction on one side and oceanunder-ocean on the other. The Caribbean continental basement blocks, named here Chortis, Acapulco, Maya, La Rana, and South Florida, were surely part of Gondwana and were fragmented by the opening of the North Atlantic when North America started rifting from Gondwana. Figures 44 – 52 show the stages of Cuban evolution described above relative to a possible plate-tectonic reconstruction of the Caribbean. The continental positions in these reconstructions are based on the reconstructions of the ODSN. The position of the Caribbean is shown in relation to Africa. Cuba is placed in its present position relative to Florida, although different parts of the island come from different places. The reconstruction shown by Figures 44–52 can explain several observations, but cannot be proven by present evidence.

Callovian The Callovian is an early stage of the opening of the Caribbean (162 Ma; see Figure 44). Spreading oc-

curred through Florida and the Gulf of Mexico, with fragmentation of the Paleozoic basement and southward motion of the resulting Chortis, Acapulco, Maya, La Rana, and South Florida blocks. The Louann and Cunagua Salt, as well as the Maraval evaporite basins, formed. This was the time of major continentalderived clastic sedimentation in the opening Caribbean, with the deposition of the Todos los Santos and the San Cayetano (and equivalent schists and quartzites of the Isle of Pines and Escambray massifs). The east-dipping Andes subduction zone is assumed to have separated the Americas from the Pacific Ocean. Cuba could have been located over one of the numerous transforms offsetting the spreading axis. Such transforms might have become later transcurrent faults, thus explaining the so-called ‘‘crustal discontinuity’’ running parallel to and north of the axis of the island.

Early Tithonian The opening between North and South America continued with a strong left-lateral component, but the spreading axis jumps south of the Paleozoic blocks (144 Ma; see Figure 45). From then on, the southern

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FIGURE 48. 94 Ma: Cenomanian. A = Africa; FL = Florida; NA = North America; SA = South America. margin of the North American continent and northern Cuba became fixed relative to each other, and the entire north coast of Cuba, from Matanzas to Oriente, became part of the North American plate. Shallowwater conditions covered much of Cuba, the Bahamas, Florida, La Rana, and Maya, and the deposition of the Florida-Bahamas-Yucatan banks began. Some of the Cayo Coco and Maraval evaporites were still being deposited. This was the time of the formation and deepening of the early Caribbean. The Maya MountainsSarasota arch, the remnant of a late Paleozoic mountain range, was an effective dam holding back the sediments derived from North America. The major marine opening was toward the Atlantic, resulting in a strong influx of Tethys faunas.

Valanginian The lower Cabaiguan* section indicates that the Caribbean continued to expand with the generation of new crust (132 Ma; see Figure 46). The rest of Cuba showed a marked increase in water depth with accumulation of calcareous nannoplankton. In southern Belize, the ‘‘Aptychus’’ limestone accumulated

in a facies identical with that of Cuba’s Capitolio*. The La Rana block appears to have remained positive with deposition of bank limestone of the Vinas* Group.

Aptian South America began to separate from Africa, and the Caribbean continued to open (110 Ma; see Figure 47). The Maya Mountains-Sarasota arch continued to prevent the Gulf of Mexico clastics from reaching the Caribbean. The shallow-water Cogollo-Chimana reef limestones of Venezuela accumulated in a facies similar to that of the Coban, Marquesas, and Cayo Coco to the north. Strong submarine (oceanic) volcanism continued as indicated by the pillow basalts of the lower Cabaiguan sequence and by the Curac¸ao lava as well as the pre-Horizon B volcanics of the Venezuelan and Colombian basins.

Albian–Cenomanian–Turonian Oceanic spreading was mostly in the North and South Atlantic (94 Ma; see Figure 48). The motion in

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FIGURE 49. 80 Ma: Santonian. A = Africa; FL = Florida; NA = North America; SA = South America.

the Caribbean was mostly transcurrent, with increasing separation between North and South America. In Cuba, this is reflected by a marked decrease in volcanic material at the base of the Cabaiguan* sequence. The Cenomanian – Turonian was characterized by decreasing volcanic flows in the Gomez* Formation (Cabaiguan* sequence), which were, however, still in proximity to basic submarine volcanism. The Gomez*, characterized by black shale and thin nodular black limestone beds, is reminiscent of the La Luna and Querecual in Venezuela and the Eagle Ford in the Gulf states. It correlates, in part, with the extensive Santa Teresa cherts and clays that are similar to the San Antonio in Venezuela and the Mowry in the Rocky Mountains. A major regional if not worldwide marine transgression was accompanied by extensive submarine volcanic activity. Perhaps the silica was contributed by volcanism along the mid-Atlantic rift.

Coniacian–Santonian–Campanian The transcurrent motion between Cuba and South America decreased from the Albian to the Maastrich-

tian, whereas the separation between North and South America increased (80 Ma; see Figure 49). During the Coniacian, a new spreading axis formed (perhaps coinciding with today’s Cayman trough and under the Curac¸ao Ridge), and subduction intensified along the boundaries facing North and South America. The subduction generated a new arclike, more acidic, volcanic sequence (Pastora* Group in Cuba, and KnipVilla de Cura in Venezuela). Pindell et al. (2006) considers that this volcanic sequence indicates the insertion of a Pacific oceanic plate (the present Caribbean) between both continents. It could as well have been generated in situ, which would agree better with the geology of Cuba.

Maastrichtian The Maastrichtian saw the initiation of the northward gravity slide of the basic igneous-volcanic terranes in western Cuba and the clockwise rotation of the Villa de Cura (Tiara volcanics) in Venezuela (67 Ma; see Figure 50). Volcanism ceased in western Cuba and greatly diminished in central Cuba. It persisted during the middle and lower Eocene in eastern

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FIGURE 50. 67 Ma: Maastrichtian. A = Africa; FL = Florida; NA = North America; SA = South America.

Cuba, Hispaniola, and Puerto Rico. The lack of metamorphism of the Cuban basic igneous-volcanic terranes was caused by their detachment from their roots and their continuous slide away from the active subduction area and toward the Florida-Bahamas Banks.

Paleocene–Middle Eocene Around the Caribbean, including Cuba, compression, gravity sliding, and other orogenic activity culminated in the early to middle Eocene (50 Ma; see Figure 51). In Cuba, the Vega*, Rosas*, and Vieja orogenic sediments accumulated at the same time as the Venezuelan Guarico Formation, Matatere flysch, and the Barquisimeto olistostrome. The synchroneity and symmetry of deformation resulted from the two bounding subduction zones that responded to similar spreading and faced opposing continents and oceans. The Lesser Antillean arc became active, and Puerto Rico trench formed as a consequence of ocean-ocean subduction. The Barbados deep-water fan, derived from the Guyana shield, was deposited and began to be overridden by the Lesser Antilles accretionary wedge. The

Curac¸ao Ridge became detached and slid northward into the Venezuelan basin.

Early Late Eocene The northern and southern parts of the Caribbean began to look as they do today, and the circumCaribbean orogeny ended (see Figure 52; 40 Ma). The Caribbean became isolated from the Pacific by the north-dipping ocean – ocean Central American subduction zone and from the Atlantic by the westdipping ocean – ocean subduction of the Lesser Antilles arc. The Chortis block moved to its present position in Central America, and the Cayman Trench pull-apart rift began. All significant tectonic activity in Cuba ended.

CONCLUSIONS Cuba rests on the site of oceanic crust that formed as North America first began to separate from the rest of Pangea in the Late Triassic to Early Jurassic. It shows the most complete assemblage of intrusive,

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FIGURE 51. 50 Ma: lower Eocene. A = Africa; FL = Florida; NA = North America; SA = South America. volcanic, and sedimentary rocks in the Caribbean region. During and after the separation of South America from Pangea in the Early Cretaceous, spreading continued in the Caribbean as well as the Atlantic and Pacific oceans. Oceanic plates were subducting under North and South America. As a result of the Caribbean rifting, a pair of opposing orogenic belts developed. Along strike, the northern subduction changed from oceanic crust under continental crust (with obduction) in Cuba to oceanic under oceanic in Hispaniola and Puerto Rico. Figure 53 shows, diagrammatically (transforms have been omitted), the possible connection between Cuba and other Greater Antilles deformation. On the south side of the Caribbean, continental and oceanic subduction (with obduction) occurred in Venezuela, and oceanic – oceanic subduction occurred in Panama (the Panama segment may have

reversed polarity during the Tertiary). Both subduction zones operated simultaneously, and analogous to the present-day Scotia Sea, there must have been a spreading axis between them. Later processes, such as those that formed the Cayman trough, probably obscured the location of the spreading axis. It is particularly interesting that the entire orogenic activity shown by the rocks of Cuba (with the exception of some subaerial volcanism) appears to have occurred below sea level. The introduction of the Chortis block, as well as the relationship with older Hercynian and Appalachian deformed belts, remains poorly understood. The end of significant tectonic activity in Cuba in the late Eocene means that the island’s geology gives no indication about the nature of the Cayman trough’s left-lateral motion nor about the apparent right-lateral transcurrent motion in northern South America.

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FIGURE 52. 40 m.y.: base upper Eocene. A = Africa; FL = Florida; NA = North America; SA = South America.

ACKNOWLEDGMENTS Gulf Oil Corporation, which was very active in Cuba in the late 1940s and 1950s, was acquired by Chevron in 1984. Gulf donated, with Chevron’s authorization, all its Cuban files and material available in the United States to the Institute of Geophysics, University of Texas, Austin. These data are now in the public domain and are available at the University of Texas. It must be mentioned that Gulf’s original reports (like those of other foreign companies), were nationalized in 1959 by the revolutionary government. Unless lost, the reports are supposedly available to the public at the Fondo Geologico, La Habana. Much of Gulf’s information was based on a field mapping campaign conducted under my direction from 1952 to 1955. Paul B. Truitt and Harry Wassall were responsible for most of the fieldwork and general stratigraphic and structural studies. Much credit is also due to P. Bro ¨ nnimann, who was in charge of the stratigraphic laboratory in La Habana, and was

assisted by N. K. Brown in paleontology and K. K. Dickson in petrography. Bro ¨ nnimann discovered the abundant presence, in Cuban strata, of Alpine nannoplankton, leading to the unraveling of much of Cuban stratigraphy (Bro ¨ nnimann, 1955a, b). M. T. Kozary, at the time a graduate student at Columbia University, was closely associated with the project. In 1990, Harry Wassall, then at Petroconsultants, requested that I write a report on the Geology and Oil Prospects of Cuba. This report, issued in 1993, was, in large part, based on the writer’s own experience, the Gulf reports at the University of Texas, and the extensive literature available at the University of Texas. Wassall and G. Winston, Geological Consultant, provided much assistance and information. After Wassall’s death, IHS Energy Group, which had acquired Petroconsultants, relinquished all rights to this material. This publication is a much revised version of the Petroconsultants report. I also thank Amos Salvador and E. Rosencrantz of the University of Texas for making the data at the Institute of Geophysics easily available, giving valuable

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FIGURE 53. Obduction over Cuba and Hispaniola.

suggestions, and participating in important discussions. The author is grateful to M. Iturralde-Vinent of Havana’s Museo Nacional de Historia Natural for providing much assistance and recent information. I am also greatly indebted to T. Anderson for many suggestions concerning the interpretation of the data and

editing parts of the manuscript. Lastly, I am terribly grateful to Andrzej Pszczo´lkowski from the Polish Academy of Sciences and author of many recent studies of Cuban geology, who reviewed the manuscript and made many suggestions for improvements, as well as providing up-to-date information.

References Cited Ball, M. M., R. G. Martin, and W. D. Bock, 1981, Multichannel measurements over a possible gas-bearing structure near Cay Sal, Bahamas: AAPG Bulletin, v. 65, no. 5, p. 894. Ball, M. M., R. G. Martin, W. D. Bock, R. E. Sylwester, R. M. Bowles, D. Taylor, E. L. Coward, J. E. Dodd, and L. Gilbert, 1985, Seismic structure and stratigraphy of northern edge of Bahaman–Cuban collision zone: AAPG Bulletin, v. 69, p. 1275 – 1294. Bazhenov, M. L., A. Pszczo´lkowski, and S. V. Shipunov, 1996, Reconnaissance paleomagnetic results from western Cuba: Tectonophysics, v. 253, p. 65– 81. Bermudez, P. J., 1950, Contribicion al estudio del Conozoico Cubano, Universidad de la Habana (in Spanish): Memoria de la sociedad Cubana de historia natural, v. 19, no. 3, p. 205–375. Bermudez, P. J., 1961, Las formaciones geologicas de Cuba: La Habana, Ministerio de Industrias, Instituto Cubano de Recursos Minerales, Geologia Cubana, no. 1, 177 p. Bermudez, P. J., and R. Hoffsteller, 1959, Lexique Stratigraphique International. Amerique Latine, Cuba, v. 5, 140 p. Bohor, B. F., and R. Seitz, 1990, Cuban K/T Catastrophe: Nature, v. 344, p. 593. Boiteau, A., and M. Campos, 1974, Data preliminares sobre la geologia de la parte sur de la Sierra del Purial (Preliminary data on the geology of the southern part of La Sierra del Purial) (Spanish): Cuba, University de Oriente. Bovenko, V. G., B. Y. Scherbakova, and G. Hernandez, 1981, Topography of the Mohorovicic discontinuity beneath eastern Cuba (in English): Transactions of the U.S.S.R. Academy of Sciences, Earth Science Sections, v. 256, p. 8 – 12. Bovenko, V. G., B. Y. Scherbakova, and G. Hernandez, 1982, New geophysical data on the deep structure of eastern Cuba: International Geology Review, v. 24, p. 1155 – 1162. Brito Rojas, A., 1983, New aspects of the subdivision of the Cobre Formation, in E. Nagy et al., eds., Contribucion a la Geologia de Cuba Oriental: Editorial CientificoTecnica, Ministerio de Cultura, Ciudad de la Habana, p. 86 – 89. *Bro¨nnimann, P., 1953a, Laboratory Memorandum PB-14: Progress biostratigraphic chart, northern Las Villas Province, Cuba, Cuban Gulf Oil Co., La Habana: Report, Library of the Institute for Geophysics, University of Texas, Austin, Texas.

Albear Franquiz, J. F. de, and M. A. Iturralde-Vinent, 1985a, Estratigrafia de las provincias de la Habana, in M. A. Iturralde-Vinent, ed., Contribucion a la geologia de las provincias de la Habana y ciudad de la Habana: Ciudad de la Habana, Editorial Cientifico-Tecnica, Ministerio de Cultura, p. 12 – 54. Albear Franquiz, J. F. de, and M. A. Iturralde-Vinent, 1985b, Pisos estructurales en el territorio de las provincias de la Habana, in M. A. Iturralde-Vinent, ed., Contribucion a la geologia de Cuba Oriental: Ciudad de la Habana, Editorial Cientifico-Tecnica, Ministerio de Cultura, p. 77 – 86. Albear Franquiz, J. F. de, and M. A. Iturralde-Vinent, 1985c, Posicion tectonica del complejo gabro-peridotitico de las provincias de La Habana, in M. A. Iturralde-Vinent, ed., Contribucion a la geologia de las provincias de la Habana y ciudad de la Habana: Ciudad de la Habana, Editorial Cientifico-Tecnica, Ministerio de Cultura, p. 87 – 93. Albear Franquiz, J. F. de, J. Sanchez Arango, and M. A. Iturralde-Vinent, 1985, Formacion Rosario: Redescripcion y estudio micropaleontologico, in M. A. IturraldeVinent, ed., Contribucion a la geologia de las provincias de la Habana y ciudad de la Habana: Ciudad de la Habana, Editorial Cientifico-Tecnica, Ministerio de Cultura, p. 59– 76. Alegret, L., I. Arenillas, J. A. Arz, C. Dı´az, J. M. GrajalesNishimura, A. Mele´ndez, E. Molina, R. Rojas, and A. R. Soria, 2005, Cretaceous–Paleogene boundary deposits at Loma Capiro, central Cuba: Evidence for the Chicxulub impact, Geology, v. 33, no. 9, p. 721–724. Alva-Valdivia, L. M., A. Goguitchaichvili, J. CobiellaReguera, J. Urrutia-Fucugauchi, M. Fundora-Granda, J. M. Grajales-Nishimura, and C. Rosales, 2001, Palaeomagnetism of the Guaniguanico Cordillera, western Cuba: A pilot study: Cretaceous Research, v. 22, p. 705– 718. Ando´, J., S. Harangi, B. Szakma´ny, and L. Doszta´ly, 1996, Petrologia de la Asociacion Ofiolitica de Holguin, in M. A. Iturralde-Vinent, ed., 1996, Ofiolitas y Arcos Volcanicos de Cuba (Cuban Ophiolites and Volcanic Arcs) (Spanish): International Union of Geological Sciences —United Nations Educational, Scientific and Cultural Organization, International Geological Correlation Programme, Contribution No. 1, Project 364 (Geological Correlation of Ophiolites and Volcanic Arc Terrane in the CircumCaribbean Realm), p. 154 – 175.

*All italicized references in this References Cited Section are unpublished reports donated by Gulf/Chevron to The University of Texas — Institute for Geophysics, and can be found listed in the UTIG Plates Project Bibliography of Caribbean Geology and Geophysics located at http://www.ig.utexas.edu/research/projects /plates/biblio/carib/carib.htm (accessed December 15, 2008).

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50 / Pardo *Bro¨nnimann, P., 1953b, Laboratory Memorandum PB-28: Progress biostratigraphic chart, northern Las Villas Province, Cuba, Cuban Gulf Oil Co., La Habana: Report, Library of the Institute for Geophysics, University of Texas, Austin, Texas. *Bro¨nnimann, P., 1954, Paleontological Report 456: Annotations to the correlation chart and catalogue of formations, Cuban Gulf Oil Co., La Habana: Report, Library of the Institute for Geophysics, University of Texas, Austin, Texas. Bro ¨ nnimann, P., 1955a, Microfossils incertae sedis from the Upper Jurassic and Lower Cretaceous of Cuba: Micropaleontology, v. 1, p. 28 – 49. *Bro¨nnimann, P., 1955b, Paleontological Report 754: Annotation to the correlation chart of the Fomento-Jatibonico area and catalogue of formations, Cuban Gulf Oil Co., La Habana: Report, Library of the Institute for Geophysics, University of Texas, Austin, Texas. *Bro¨nnimann, P., 1956, Paleontological Report 1148: Annotations to the correlation chart of northern Las Villas Province, Cuban Gulf Oil Co., La Habana: Report, Library of the Institute for Geophysics, University of Texas, Austin, Texas. Bro ¨ nnimann, P., and D. Rigassi, 1963, Contribution to the geology and paleontology of the area of the city of La Habana, Cuba, and its surroundings: Eclogae Geologicae Helvetiae, v. 56, p. 1–480. Burke, K., 1988, Tectonic evolution of the Caribbean: Annual Review of Earth and Planetary Sciences, v. 16, p. 201 – 230. Bush, V. A., and I. N. Shcherbakova, 1986, New data on the deep tectonics of Cuba: Geotectonics, v. 20, no. 3, p. 192 – 203. *Butticaz, P., 1952, Gas seepages in the Keys east of the Isle of Pines, Cuba, Standard Cuban Oil Company, La Habana: Report, Library of the Institute for Geophysics, University of Texas, Austin, Texas. *Calvache, G., 1958, Final report on Collazo 1 well, Cuban Gulf Oil Co., La Habana: Report, Library of the Institute for Geophysics, University of Texas, Austin, Texas. Cerma´k, V., M. Kresl, J. Safanda, M. Na´poles-Pruna, R. TenreyroPerez, L. M. Torres-Paz, and J. J. Valdes, 1984, First heat flow density assessments in Cuba: Tectonophysics, v. 103, p. 283 – 296. Cerma´k, V., M. Kresl, J. Safanda, L. Bodri, M. Na´poles-Pruna, and R. Tenreyro-Perez, 1991, Terrestrial heat flow in Cuba: Physics of the Earth and Planetary Interiors, v. 65, p. 207 – 209. Chauvin, A., M. L. Bazhenov, and T. Beaudouin, 1994, A reconnaissance paleomagnetic study of cretaceous rocks from central Cuba: Geophysical Research Letters, v. 21, no. 16, p. 1691 – 1694. Childs, O. E., G. Steele, and A. Salvador, eds., 1988, Correlation of stratigraphic units of North America (COSUNA) Project, Gulf Coast Region, AAPG, Tulsa, Oklahoma, 1 sheet. Cobiella, J. L., 1974, Los macizos serpentiniticos de Saba-

nilla Mayari Arriba (Serpentine Massifs of Sabanilla, Mayari Arriba) (Spanish): Revista Tecnologica, v. 12, no. 4, p. 41–50. Cobiella, J., F. Quintas, M. Campos, and M. M. Hernandez, 1984, Geology of the central and southeast region of Guantanamo province: Santiago de Cuba, Editorial Oriente, 125 p. Cobiella-Reguera, J. L., 2005, Emplacement of Cuban ophiolites: Geologica Acta, v. 3, no. 3, p. 273 – 294. Coutı´n-Correa, D., and A. Brito-Rojas, 1976, Caracteristicas de la Zeolitizacio´n de las rocas Sedimentarias de origen volcanico de Cuba oriental (Characteristics of the Zeolitization of the Sedimentary Rocks of Volcanic Origin of Eastern Cuba): Transactions of the Caribbean Geological Conference, Flushing, NY, Queens College Press, p. 293–297. Cuba, 1985a, Mapa Geologica de la Republica de Cuba: Ministerio de la Industria Basica, Centro de Investigaciones Geologicas, scale 1:500,000, 5 sheets. Cuba, 1985b, Mapa Tectonico de Cuba: Ministerio de la Industria Basica, Centro de Investigaciones Geologicas, scale 1:500,000, 4 sheets. Cuba, 1988, Mapa de Yacimientos y Manifestaciones Minerales no Metalicos y Combustibles de la Republica de Cuba: Academy of Sciences of Cuba and USSR, scale 1:500,000, 5 sheets. Cuevas Ojeda, J. L., L. A. Dı´az Larrinaga, and B. P. Gonza´lez, 2003, Mapas generalizados de las anomalias gravimetricas del Caribe Occidental y America Central, 1:2,000,000: Tectonic of Caribbean plates, International Geological Correlation Programme – United Nations Educational, Scientific, and Cultural Organization Project 433, Memorias GEOMIN (Geologia y Mineria) (Spanish): La Habana, 9 p. Dalziel, I. W. D., 1974, Evolution of the margins of the Scotia Sea, in C. H. Burk and C. L. Drake, eds., The geology of continental margins: New York, Springer Verlag, p. 567– 579. Darton, N. H., 1926, Geology of Guantanomo Basin, Cuba: Journal of the Washington Academy of Science, v. 16, p. 324 – 333. DeGolyer, E., 1918, The geology of Cuban petroleum deposits: AAPG Bulletin, v. 2, p. 133 – 167. Dengo, G., 1975, Paleozoic and Mesozoic tectonic belts in Mexico and Central America, in A. E. Nairn and F. G. Stehli, eds., The ocean basins and margins: The Gulf of Mexico and the Caribbean: New York, Plenum Press, v. 3, p. 283 – 323. Dengo, G., and J. E. Case, eds., 1990, The Caribbean region, decade of North American geology (DNAG), The Geology of North America, V.H.: Geological Society of America, 528 p. De Vletter, D. R., 1946, Geology of the western part of the Middle Oriente, Cuba: Doctoral thesis, Kemink, University of Utrecht, Netherlands, 106 p.

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References / 51 Dilla, M., and L. Garcı´a, 1984, Stratigraphy and sedimentogenesis of the superpositioned basins of central Cuba (in Spanish): Serie Geologica, Instituto de Geologia y Paleontologia Academia de Ciencias de Cuba, p. 101 – 154. Dilla, M., and L. Garcia, 1985, New data on the stratigraphy of the provinces of Cienfuegos, Villa Clara and SanctiSpiritus (in Spanish): Serie Geologica, Instituto de Geologia y Paleotologia Academia de Ciencias de Cuba, p. 53 – 77. Ducloz, C., 1960, Apuntes sobre el yeso del Valle de Yamuri, Matanzas (Notes on the gypsum of Valle de Yamuri, Matanzas) (Spanish): Sociedad Cubana de Historia Natural, Memorias, v. 28, no. 1, p. 1–9. Ducloz, C., 1963, Geomorphic study of the region of Matanzas, Cuba: Archives tes Sciences, Societe de Physique et Histoire Naturelle, v. 16, p. 351 – 402. Ducloz, C., and M. Vaugnat, 1962, On the age of serpentines of Cuba: Archives tes Sciences, Societe de Physique et Histoire Naturelle, v. 15, p. 310 –331. Echevarria-Rodriguez, G., G. Hernandez-Perez, J. O. Lopez Quintero, J. G. Lopez-Rivera, R. Rodriguez-Hernandez, J. R. Sanchez-Arango, R. Socorro-Trujillo, R. TenreyroPerez, and J. L. Yparraguirre-Pena, 1991, Oil and gas exploration in Cuba (in Spanish): Journal of Petroleum Geology, v. 14, p. 259 – 274. Fernandez, G., J. Fernandez, and S. Blanco-Bustamante, 1987, Estudio biostratigrafico y ambientes de sedimentacion del pozo Candelaria 1 de la provincia de Pinar del Rio, in Memorias del III Encuentro Cientifico-Tecnico de Geologia, P. del Rio, October 24, 1987: p. 32– 39. Flint, D. E., J. F. Albear, and P. W. Guild, 1948, Geology of chromite deposits of the Camaguey district, Camaguey Province, Cuba: U.S. Geological Survey Bulletin, v. 954, p. 39 – 63. *Flores, G., 1949, Western Matanzas Province, 20, Cuban Gulf Oil Co., La Habana: Report, Library of the Institute for Geophysics, University of Texas, Austin, Texas. Flores, G., 1952, Geology of northern British Honduras: AAPG Bulletin, v. 36, p. 404 – 413. Franco, G. L., 1983a, Considerations about the OligoMiocene deposits of Guantanamo, in E. Nagy et al., eds., Contributions on the geology of eastern Cuba (in Spanish): La Habana, Editorial Cientifico-Tecnica, p. 138 – 143. Franco, G. L., 1983b, Geologic column of the Tertiary of the Golfo de Guacanayabo (in Spanish), in E. Nagy et al., eds., Contribucion a la geologia de Cuba Oriental: Ciudad de la Habana, Editorial Cientifico-Tecnica, p. 127–133. Franco, G. L., 1985, Tectono-environmental classification of Neogene deposits in eastern Cuba: Ciencias de la Terra y del Espacio, no. 10, p. 57–67. Franco, G. L., 1986, Scheme of the history of sedimentation during the Neogene in eastern Cuba: Ciencias de la Terra y del Espacio, no. 11, p. 81 – 91.

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52 / Pardo Haczewski, G., 1987, Reconocimiento sedimentologico de la Formacion San Cayetano: Un margen continental acumulativo en el Jurasico de Cuba occidental, in A. Pszczo´lkowski et al., eds., Contribucion a la geologia de la provincia de Pinar del Rio: Ciudad de La Habana, Ministerio de Cultura, Editorial Cientifico-Tecnica, p. 228 – 247. Hatten, C. W., 1957, Geology of the Central Sierra de los Organos, Pinar Del Rio Province, Cuba, Report found at the Library of the Institute for Geophysics, University of Texas, Austin, Texas, 48 p. Hatten, C. W., 1967, Principal features of Cuban geology: Discussion: AAPG Bulletin, v. 51, p. 780 – 789. *Hatten, C. W., D. E. Schooler, N. Giedt, and A. A. Meyerhoff, 1958, Geology of central Cuba, eastern Las Villas and western Camaguey Provinces, Cuba: Report, Library of the Institute for Geophysics, University of Texas, Austin, Texas, 174 p. Hatten, C. W., M. Somin, G. Millan, P. Renne, R. W. Kistler, and J. M. Mattinson, 1988, Tectonostratigraphic units of central Cuba, in L. Barker, ed., Transactions of the 11th Caribbean Geological Conference, Barbados, 1986: p. 35.1– 35.13. Hedberg, H. D., ed., 1976, International Stratigraphic Guide, John Wiley & Sons, New York, New York, 200 p. Hermes, J. J., 1945, Geology and paleontology of East Camaguey and West Oriente: Geographische en Geologische Mededeelingen, Physiographisch-Geologische Reeks, Series 7: Utrecht, Holland, Instituut der Rijksuniversiteit, 75 p. Hernandez Perez, G., and J. F. Blickwede, 2000, Cuba deepwater exploration opportunities described in southeastern Gulf of Mexico: Oil & Gas Journal, v. 98, no. 50, p. 42 – 48, 46 – 48. Herrera, N., 1961, Contribution to the Stratigraphy of the Pinar del Rio Province (in Spanish): Revista Sociedad Cuban Ingenieria, v. 61, no. 1-2, p. 2 – 24. Hess, H. H., 1938, Gravity anomalies and island arc structure with particular reference to the West Indies: Proceedings of the American Philosophical Society, v. 79, no. 1, Symposium on the Geophysical Exploration of the Ocean Bottom, arranged by the American Geophysical Union, April 21, 1938, p. 71 – 96. Holcombe, T. L., J. W. Ladd, G. Westbrook, N. Terrence Edgar, and C. L. Bowland, 1990, Caribbean marine geology, ridges and basins of the plate interior, in G. Dengo and J. E. Case, eds., The geology of North America, v. H: The Caribbean region: Geological Society of America, p. 231 – 260. Imlay, R. W., 1942, Late Jurassic fossils from Cuba and their economic significance: Geological Society of America Bulletin, v. 53, p. 1417 – 1477. Ipatenko, S., and I. N. Sashina, 1971, Sobre el levantamiento gravimetrico en Cuba: Ministerio de Minas, La Habana, Cuba (in Spanish), 14 p. Ipatenko, S., M. Kopnin, and S. Shijov, 1971, Using gravi-

metric exploration to study the crustal structure of the island of Cuba and adjacent territory (in Spanish): Revolucion Tecnologica, v. 9, no. 2, p. 40 – 46. Iturralde-Vinent, M., 1988, Naturaleza Geologica de Cuba: Editorial Cientifico-Technica, La Habana, 246 p. Iturralde-Vinent, M., et al., 1981, Geologica del territorio de Ciego-Camaguey-Las Tunas: Resultados de las investigaciones cientificas y del levantamiento geolo´gico escala 1:250,000: Academias de ciencias de Cuba y Bulgaria, 940 p. Iturralde-Vinent, M. A., 1969, Neogene stratigraphy in western Cuba: New data: AAPG Bulletin, v. 54, p. 1938 – 1955. Iturralde-Vinent, M. A., 1970, Principal characteristics of Cuban Neogene stratigraphy: AAPG Bulletin, v. 53, p. 658– 661. Iturralde-Vinent, M. A., 1972, Principal characteristics of the Oligocene and Lower Miocene stratigraphy of Cuba (in Spanish): Revolucion Tecnologica, v. 10, no. 3 – 4, p. 24 – 35. Iturralde-Vinent, M. A., 1975a, Problems in the application of modern tectonic hypotheses to Cuba and the Caribbean region: AAPG Bulletin, v. 59, p. 838 – 855. Iturralde-Vinent, M. A., 1975b, Problems with the application of modern hypotheses to Cuba and the Caribbean region: Revolucion Tecnologica, v. 13, no. 1, p. 46 – 63. Iturralde-Vinent, M. A., 1977, The tectonic movements during the platform development stage in Cuba (in Spanish): Informe Cientifico-Tecnico, v. 20, p. 1 – 24. Iturralde-Vinent, M. A., 1981, New interpretative model of the geological evolution of Cuba (in Spanish): Ciencias de la Tierra y del Espacio, v. 3, p. 51 – 89. Iturralde-Vinent, M. A., 1985, Historia geologica del Mesozoico de las provincias de La Habana, in M. A. IturraldeVinent, ed., Contribucion a la geologia de las provincias de la Habana y ciudad de La Habana: Ciudad de la Habana, Editorial Cientifico-Tecnica, Ministerio de Cultura, p. 94–99. Iturralde-Vinent, M. A., 1994, Cuban geology: A new plate tectonic synthesis: Journal of Petroleum Geology, v. 17, no. 1, p. 39 – 70. Iturralde-Vinent, M. A., ed., 1996, Ofiolitas y arcos volcanicos de Cuba (Cuban ophiolites and volcanic arcs), in International Union of Geological Sciences – United Nations Educational, Scientific, and Cultural Organization International Geological Correlation Programe, Contribution 1, Project 364, (Geological Correlation of Ophiolites and Volcanic Arc Terrane in the CircumCarribean Realm), 254 p. Iturralde-Vinent, M. A., 1998, Sinopsis de la constitucio´n geolo´gica de Cuba: Acta Geologica Hispanica, v. 33, no. 1 – 4, p. 9 – 56. Iturralde-Vinent, M. A., and A. C. de la Torre, 1990, Posicion estratigrafica de los rudistas de Camaguey, Cuba, in D. K. Larne and G. Draper, eds., Transactions, 12th

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ternational Union of Geological Sciences-United Nations Educational, Scientific and Cultural Organization (Geological Correlation of Ophiolites and Volcanic Arc Terrane in the Circum-Caribbean Realm): International Geological Correlation Programme, Contribution No. 1, Project 364, 254 p. *Kozary, M., 1955a, Geology of the Campo Florida section of the Habana-Matanzas anticline (Geological Memorandum MK-3), Cuban Gulf Oil Co., La Habana: Report, Library of the Institute for Geophysics, University of Texas, Austin, Texas. *Kozary, M., 1955b, Geology of the Ciego de Avila-Tamarindo area, Camaguey (Geological Memorandum MK-4), Cuban Gulf Oil Co., La Habana: Report, Library of the Institute for Geophysics, University of Texas, Austin, Texas. Kozary, M. T., 1968, Ultramafic rocks in thrust zones of northwestern Oriente province, Cuba: AAPG Bulletin, v. 52, p. 2298 – 2317. Kuznetsov, V. I., J. R. Sanchez, G. Furrazola, and R. Garcia, 1985, New data on the thrust sheets of the north coast of Cuba (in Spanish): Serie Geologica, Instituto Geologia y Paleontologia Academia de Ciencias de Cuba, p. 106 – 118. Lewis, J. M., 1932, Geology of Cuba: AAPG Bulletin, v. 16, no. 6, p. 533-555. *Littlefield, M., 1952, Summary report: Cuban Gulf Oil Co. Blanquizal 111 #1, Cuban Gulf Oil Co., La Habana: Report, Library of the Institute for Geophysics, University of Texas, Austin, Texas. Lopez-Rivera, J. G., J. O. Lopez Quintero, J. Fernandez Carmona, and G. Fernandez Rodriguez, 1987, Analisis geologica del corte del pozo Parametrico Pinar 1: In Memorias del III Encuentro Cientifico-Tecnico de Geologia, P. Del Rio, October 24, 1987, p. 40– 45. MacGillarry, H. J., 1937, Geology of the province of Camaguey, Cuba, with revisional studies in rudist paleontology: Geographische en Geologische Mededeelingen. Physiographisch-Geologische Reeks, Series 14: Utrecht, Holland, Instituut der Rijksuniversiteit, 169 p. Meyerhoff, A. A., and C. W. Hatten, 1968, Diapiric structures in central Cuba, in J. Braunstein and G. D. O’Brien, eds., Diairism and diapirs: AAPG Memoir 8, p. 315 – 357. Meyerhoff, A. A., M. M. Khudoley, and C. W. Hatten, 1969, Geologic significance of radiometric dates from Cuba: AAPG Bulletin, v. 53, p. 2494 – 2500. Milla´n, G., 1981, Geology of the metamorphic massif of the Isla de la Juventud Ciencias de la Tierra y del Espacio, no. 3, p. 3 – 22. Milla´n G., 1992, Analisis comparativo entre los macizos metamorficos de Isla de la Juventud y Escambray (Comparative analysis between the Metamorphic Massifs of Isla de la Juventud and Escambray): Programa y resu´menes 13va Conferencia Geolo´gica del Caribe, Pinar del Rio, Cuba, p. 53 – 54. Milla´n, G., and R. Myczynski, 1979, Jurassic ammonite

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Adamovich, A. F., and V. Chejovich, 1964, Principal characteristics of the geology and the useful minerals of the northeast region of Oriente Province: Revistas Tecnologica (Spanish), v. 2, no. 1, p. 14 – 20. Bandy, O., 1964, Foraminiferal biofacies in sediments of the Gulf of Batabano, Cuba, and their geologic significance: AAPG Bulletin, v. 48, p. 1666 – 1679. Bresznyanszky, K., and M. A. Iturralde-Vinent, 1983, Paleogeografia del Paleogeno de Cuba Oriental, in E. Nagy et al., eds., Contribucion a la Geologia de Cuba Oriental: Ciudad de la Habana, Editorial Cientifico-Tecnica, Ministerio de Cultura (Spanish), p. 115 – 126. Bresznyanszky, K., and M. A. Iturralde-Vinent, 1985, Paleogeografia del Paleogeno de las provincias de La Habana, in M. A. Iturralde-Vinent, ed., Contribucion a la Geologia de Las Provincias de La Habana y Ciudad de La Habana: Ciudad de la Habana, Editorial CientificoTecnica, Ministerio de Cultura (Spanish), p. 100 – 115. Campos, M., and M. Hernandez, 1990, Correlacion de las Metavulcanitas de la Sierra del Purial (Cuba Oriental) con las Rocas de la Asociacion Ofiolitica, in D. K. Larue and G. Draper, eds., Transactions of the 12th Caribbean Geological Conference, St. Croix, U. S. Virgin Islands, 1989: Miami, Florida, Miami Geological Society (Spanish), p. 95 – 98. Cruz Ferra´n, C., 2000, Paleomagnetic studies of Jurassic to Tertiary rocks in Jamaica and Cuba (abs.): Licentiate thesis, Samha¨llsbyggnadsteknik/Tilla¨mpad geofysik, Sweden: http://epubl.luth.se/1402-1757/2000/59/index.html (accessed October 15, 2008). Diaz de Villalvilla, L., 1985, Proposal for a division of the socalled Tobas Formation (Cienfuegos, Villa Clara and Sancti Spiritus Provinces): Serie Geologica 1, Instituto de Geologia y Paleontologia, Academia de Ciencias de Cuba (Spanish), p. 133 – 154. Donnelly, T. W., G. S. Horne, R. C. Finch, and E. Lo´pezRamos, 1990, Northern Central America, the Maya and Chortis Block, in G. Dengo, ed., The geology of North America vol. H, The Caribbean region: The Geological Society of America, p. 37 – 76. Echevarria, H., N. V. Shablinskya, and V. I. Shatsilov, 1974, New data on the crustal structure of western Cuba (English, translation of Russian article): International Geological Review, v. 16, p. 59 – 61. Fonseca, E., F. Castillo, A. Uhanov, M. Navarette, and G. Correa, 1990, Geoquimica de la Asociacion Ofiolitica de Cuba, in D. K. Larue and G. Draper, eds., 12th Caribbean Geological Conference, St. Croix, U. S. Virgin

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60 / Pardo Lopez Ramos, E., 1975, Geological summary of the Yucatan Peninsula, in A. E. Nairn and F. G. Stehli, eds., The ocean basins and margins, vol. 3: The Gulf of Mexico and the Caribbean: New York, Plenum Press, p. 257 – 282. Malinovski, Y. M., R. Segura Soto, E. Fonseca, N. Garcia, and L. Antonenko, 1974, New data on the lithology and stratigraphy of Mesozoic and Cenozoic deposits of the north coast of Cuba (Habana-Matanzas): Revista Tecnologica (Spanish), v. 2, p. 36 – 42. Nagy, E., and D. P. Coutin, 1980, Formal and informal lithostratigraphic subdivisions in the former province of Oriente: Informe Cientifico-Tecnico 109, Academia de Ciencias de Cuba (Spanish), 7 p. Pardo, M., V. Bello, H. Amador, S. Taba, O. Sousin, I. Matamoros, and I. de Moya, 1990, Interpretacion de los Datos Geofisicos con Fines de la Cartografia GeologoEstructural de la Republica de Cuba, in D. K. Larue and G. Draper, eds., Transactions of the 12th Caribbean Geological Conference, August 7–11, 1989: Miami, Florida, Miami Geological Society (Spanish), p. 43–50. Pe´rez Estrada, L. M., J. Ferna´ndez Carmona, J. Herna´ndez, C. Perera, M. Ronda, and C. Lariot, 2001, Analisis biofacial de la Formacio´n Vega Alta sello regional de la franja de crudos pesados de la costa norte de Cuba, in Geologı´a y Minerı´a, La Habana, 19 – 23 de Marzo (Geologı´a del petroleo): GeoMin 2001, La Habana, Cuba (CD-ROM, Spanish). Perez-Parcareu, L. J., 1977, Geologic-geophysic considerations on northern Pinar Del Rio: Ciencias Tecnicas: Library of Institute for Geophysics, University of Texas, Austin (Spanish), p. 117 – 131. Piotrowska, K., 1987, Interrelationship of terranes in western and central Cuba: Tectonophysics, v. 220, p. 1 – 10. Piotrowski, J., 1986, The nappe units in the Yumuri and Caunavaco valleys: Bulletin of the Polish Academy of Sciences, Earth Sciences (Spanish), v. 34, p. 29 – 36. Piotrowski, J., 1987a, La actividad volcanica en el Mesozoico y el Paleogeno (?) de la provincia de Pinar Del Rio, in A. Pszczolkowski et al., eds., Contribucion a La Geologia de La Provincia de Pinar Del Rio: Ciudad de La Habana, Editorial Cientifico-Tecnica, Ministerio de Cultura (Spanish), p. 157 – 162. Piotrowski, J., 1987b, Nuevos datos sobre los sedimentos de Cretacico Superior Tardio y el Paleogeno en la zona estructuro-facial de San Diego de los Banos, in A. Pszczolkowski et al., eds., Contribucion a La Geologia de La Provincia de Pinar Del Rio: Ciudad de La Habana, Editorial Cientifico-Tecnica, Ministerio de Cultura (Spanish), p. 185 – 196. Piotrowski, J., and R. Myczynski, 1986, The volcanogenicsedimentary deposits of the Zaza Zone in Matanzas Province: Bulletin of the Polish Academy of Sciences, Earth Sciences (Spanish), v. 34, p. 50 – 66. Pszczo´lkowski, A., 2000, New data on late Albian and late Cenomanian nannoconid assemblages from Cuba: Bulletin of the Polish Academy of Sciences, Earth Sciences, v. 48, no. 2, p. 135 – 149.

Pugaczewska, H., 1978, Jurassic pelecypods from Cuba: Acta Palaeontologica Polonica, v. 23, p. 163 – 186. Pushcharovsky, Y., A. L. Vtulochkin, A. A. Mossakovskiy, G. Y. Nekrasov, and S. D. Sokolov, 1987, Crustal structure and types of Cuba: Transactions of the USSR Academy of Science, Earth Science Sections (English, translation of Russian article), v. 294, p. 47 – 50. Renne, P. R., 1991, Appendix: 40AR/39AR data and thermochronologic implications for a block from the Jagua Clara melange of the Rio San Juan Complex in Hispaniola, in P. Mann, G. Draper, and J. Lewis, eds., Geologic and tectonic development of the North America-Caribbean plate boundary: Geological Society of America Special Paper 295, p. 91 – 95. Rojas-Agramonte, Y., F. Neubauer, A. V. Bojar, E. Hejl, R. Handler, and D. E. Garcia-Delgado, 2005, Geology, age and tectonic evolution of the Sierra Maestra Mountains, southeastern Cuba: Geologica Acta, v. 4, no. 1 – 2, p. 123– 150. Schneider, J., D. Bosch, P. Monie´, S. Guillot, A. Garcı´a-Casco, J. M. Lardeaux, R. Luı´s Torres-Rolda´n, and G. Milla´n Trujillo, 2004, Origin and evolution of the Escambray Massif (central Cuba): An example of HP/LT rocks exhumed during intraoceanic subduction: Journal of Metamorphic Geology, v. 22, p. 227. Segura-Soto, R., et al., 1985, Lithological complexes on the northwestern end of Cuba and their stratigraphic implications as per data obtained in deep bore holes: Revista Tecnologica (Spanish), v. 15, no. 1, p. 32 – 35. Shein, V. S., R. Tenreyro-Perez, and E. Garcia-Alvarez, 1985, Model of the deep geologic structure of Cuba: Serie Geologica 1, Instituto de Geologia y Paleontologia, Academia de Ciencias de Cuba (Spanish), p. 78– 88. Sigurdsson, H., S. Kelley, R. M. Leckie, S. Carey, T. Bralower, and J. King, 2000, History of circum-Caribbean explosive volcanism: 40Ar/39Ar dating of tephra layers: Proceedings of the Ocean Drilling Program, scientific results, Leg 165: College Station, Texas, Texas A & M University, v. 165, p. 299 – 314. Solsona, J. B., and C. M. Khudoley, 1964, Tectonic sketch of the history of the geologic evolution of Cuba: Revista Tecnologica (Spanish), v. 2, no. 1, p. 4 – 13. Talavera-Coronel, F., B. Echevarria, D. Tchounev, S. Ivanev, and T. Tzankov, 1986, General characteristics of volcanism in the region Ciego de Avila-Camaguey-Las Tunas (Cuba): Ciencias de la Tienra y del Espacio (Spanish), no. 11, p. 15 – 24. Tenreyro-Perez, R., R. Otero, and G. Barcelo, 1986, Complex interpretation of geophysical data in the north of Cuba: Serie Geologica 3, Instituto de Geologia y Paleontologia, Academia de Ciencias de Cuba (Spanish), p. 73 – 87. Terence, E. N., W. P. Dillon, C. Jacobs, L. M. Parson, K. M. Scanion, and T. L. Holcombe, 1990, Structure and spreading history of the central Cayman Trough, in D. K. Larue and G. Draper, eds., 12th Caribbean Geological Conference, St. Croix, U. S. Virgin Islands, 1989: Miami, Florida, Miami Geological Society, p. 33–42.

Catalog of Stratigraphic Units CUBAN GULF VERSUS 1988 CUBAN GEOLOGIC MAP (PUSHCHAROVSKY ET AL., 1988) TERMINOLOGY

Contrabando Formation = Incl. in Guaney Formation Mayajigua Formation = not recognized Jaula Formation = Venero Formation (in part) Turiguano´ = Venero Formation (in part)

1988 Cuban geologic map (Pushcharovsky et al., 1988) terminology is underlined; areas are in italics. Incl. = included.

SAGUA LA CHICA BELT = INCL. IN CAMAJUANI ZONE Sagua Formation = Vega Formation-Breccia Sagua (in part)

YAGUAJAY BELT = REMEDIOS ZONE Las Villas Vin ˜as Group = Remedios Group Guani Formation = not recognized Bartolome´ Formation = not recognized Puntilla Formation = not recognized Palenque Formation = not recognized Camaco Formation = Incl. in Remedios Group Palone Formation = Incl. in Remedios Group Mayajigua Formation = Incl. in Remedios Group Remedios Formation = Incl. in Remedios Group Grande Formation = Incl. in Remedios Group Sagua Formation = Grande Formation (in part) San Martin Formation = Caibarien Formation (in part?) Vega Formation = not recognized Lower Vega Member = not recognized Upper Vega Member-Rosas = not recognized Caibarien Formation = Caibarien Formation (in part)

JATIBONICO BELT = INCL. IN REMEDIOS ZONE Guani Formation = Incl. in Remedios Group Mabuya Formation = Incl. in Remedios Group Florencia Formation = Incl. in Remedios Group Mayajigua Formation = Incl. in Remedios Group Sagua Formation = Embarcadero Formation (in part) San Martin Formation = Embarcadero Formation (in part) LAS VILLAS BELT = CAMAJUANI ZONE La Trocha Group = La Trocha Formation Hollo Colorado Formation = Incl. in La Trocha Formation Jaguita Formation = Incl. in La Trocha Formation Caguaguas Formation = Incl. in La Trocha Formation Penton Group Capitolio Formation = Margarita Formation, Paraiso Formation (in part) Remblazo Formation = Paraiso Formation (in part) Sabanilla Formation = not recognized (incl. in Margarita? and Paraiso ?) Malpaez Group Calabazar Formation = Incl. in Mata Formation Mata Formation = Incl. in Mata Formation Lutgarda Formation = Lutgarda Formation Sagua Formation = Incl. in Vega Formation-Breccia Sagua Camajuani Formation = Incl. in Vega FormationBreccia Sagua San Martin Formation = Incl. in Vega FormationBreccia Sagua Vega Formation = Incl. in Vega Formation-Breccia Sagua

YAGUAJAY BELT = REMEDIOS ZONE Camaguey (Sierra de Cubitas) Vin ˜as Group = Remedios Group Sagua Formation = Embarcadero Formation (in part) San Martin Formation = Embarcadero Formation (in part) Vega Formation Lower Vega Member = not recognized Upper Vega Member-Rosas = Senado Formation Caibarien Formation = Lesca Formation COASTAL REGION = CAYO COCO? Punta Alegre Formation = Punta Alegre Formation Cayo Coco Formation = ? Guillermo Formation = Incl. in Guaney Formation Romano Formation = Incl. in Guaney Formation 61

62 / Catalog of Stratigraphic Units

Lower Vega Member = Incl. in Vega FormationBreccia Sagua Upper Vega Member-Rosas = Incl. in Vega Formation-Breccia Sagua PLACETAS BELT = PLACETAS BELT (in part) Ronda Formation = Veloz Formation Constancia Formation = Constancia Formation (in part) Carmita Formation = Carmita Formation Encrucijada Member = not recognized Bermejal Member = not recognized Corona Formation = Amaro Formation CIFUENTES BELT = PLACETAS BELT (in part) Jobosi Formation = Constancia Formation (in part) Ronda Formation = Veloz Formation Constancia Formation = Constancia Formation (in part) Carmita Formation = Carmita Formation Encrucijada Member = not recognized Santa Teresa Formation = Santa Teresa Formation Amaro (incl. Macagua) Formation = Incl. in Amaro Formation Rodrigo Formation = Incl. in Amaro Formation DOMINGO SEQUENCE = ZAZA ZONE (in part) Venega Formation = not recognized (mapped as igneous) Andre´s Formation = not recognized (mapped as igneous) Cumbre Formation = Zurrapandilla Formation (in part) Miguel Formation = Incl. in Vega Alta Formation Note: The 1988 geologic map shows an extensive development of the Vega Alta Formation of middle– lower Eocene described as an olistostrome. Gulf considered it a tectonic mixture of Cifuentes, Domingo, and Cabaiguan (including Miguel, ophicalcite, and rubble zones) belts; not a true sediment. CABAIGUAN SEQUENCE = ZAZA ZONE (in part) North Seibabo´ syncline ‘‘Old Volcanics’’ = Matagua´ Formation (in part), Los Pasos Formation Obregon Formation = Incl. in Matagua´ Formation Barro Formation = Incl. in Matagua´ Formation Huevero Formation = not recognized Gomez Formation = Gomez Member of the Provincial Formation Bruja Formation = Bruja Formation (in part)

Felipe Formation = Felipe Formation of the Tassajera Group Cotorro Formation = Cotorro Formation of the Tassajera Group Curamaguey Formation = Incl. in Tassajera Group Yaya Formation = Incl. in Tassajera Group Algarrobos Formation = Incl. in Tassajera Group Bernia Formation = Santa Clara Formation (in part) South Seibabo´ syncline ‘‘Old Volcanics’’ = Matagua´ Formation (in part), Los Pasos Formation Relampago Formation = Incl. in Matagua´ Formation Matagua´ Formation = Incl. in Matagua´ Formation Cristobal Formation = Incl. in Provincial Formation Casanova Formation = Incl. in Provincial Formation Seibabo´ Formation = Seibabo´ Formation Pastora Group = Bruja Formation Bruja Formation = Incl. in Bruja Formation Pastora Formation = Incl. in Bruja Formation Agabama Formation = Incl. in Bruja Formation Escambray Formation = Incl. in Bruja Formation Salvador Formation = Incl. in Tassajera Group Palmarito Member = Palmarito Formation of the Tassajera Group Maguey Member = Maguey Formation of the Tassajera Group Cotorro Formation = not recognized Hilario Formation = Hilario Formation of the Tassajera Group Tamarindo-Camajuani area ‘‘Old Volcanics’’ = Zurrapandilla Formation (in part) Gomez Formation = not recognized Cotorro Formation = not recognized Hilario Formation = not recognized Carlota Formation = Incl. in Carlota Formation Flow Breccia Member = not recognized Porphyry Member = not recognized Rana Member = not recognized Turino Formation = Incl. in Carlota Formation Jiquimas Formation = Incl. in Carlota Formation Taguasco Formation Fomento-Taguasco area (Taguasco vicinity) ‘‘Old Volcanics’’ = Incl. in Matagua´ Formation Viajaca Formation = not recognized Potrerillos Formation = not recognized Satasa Formation = not recognized Undifferentiated tectonized Cretaceous Volcanics Taguasco Formation = Taguasco Formation

Pardo / 63

Lucia Formation = Incl. in Bijabo Formation Bijabo Formation = Incl. in Bijabo Formation Siguaney Formation = Incl. in Siguaney Formation (Loma Iguara) Rubio Formation = Incl. in Siguaney Formation Fomento-Taguasco area (Fomento vicinity) ‘‘Old Volcanics’’ = Incl. in Matagua´ Formation Jucillo Formation (Upper Cretaceous) = Jucillo Formation (lower Eocene) Isabel Formation = Incl. in Perseverancia Formation Fomento Formation = Incl. in Bijabo Formation Santo Domingo-Santa Clara area ‘‘Old Volcanics’’ = Incl. in Matagua´ Formation Corojo Formation = Incl. in Matagua´ Formation? Hatillo Formation = Incl. in Matagua´ Formation

Diego Formation = Albian –Cenomanian(?) Bruja Formation = not recognized Bayate (Bruja) Formation = not recognized Felipe Formation = Incl. in Tassajera Group Lower Member = Incl. in Tassajera Group Middle Member (Roble) = Incl. in Tassajera Group Upper Member = Incl. in Tassajera Group Cotorro Formation = not recognized Belico Formation = not recognized Bernia (Santa Clara?) Formation = Santa Clara Formation? Santa Clara Formation = Santa Clara Formation Lower – Middle Eocene Units = Ochoa Formation Vega Formation = Incl. in Ochoa Formation Vicente Formation = Incl. in Ochoa Formation Falcon Formation = Incl. in Ochoa Formation

Formation Index Anco´n Formation, 153 – 165, 171 Andre´s* Formation, 62, 150, 199 Apolo, 233 Apolo Formation, 233 Arroyo Cangre Formation, 180 Artemisa (La Trocha* Group) Formation, 117, 336 Artemisa Formation, 18, 19, 26, 123, 150, 151, 157, 164, 174 Bacunayagua Formation, 32 Bacuranao Member, 242 Bahia conglomerate, 242 Barraderas Member, 256 Barrancas Formation, 261, 262 Barro* Formation, 62, 206, 213 Bartolome´* Formation, 61, 95, 96, 108, 111, 119, 145 Basement, 15, 17, 19, 26, 40, 41, 133, 150, 183 Bayamo Formation, 287, 289 Bayate* Formation, 63, 219 Belico* Formation, 63, 209, 221, 227 Bermejal* Member, 62, 129 Bernia *Formation, 63, 209 Bernia* Formation, 63, 209 Bijabo* Formation, 32, 63, 218, 219 Bitirı´ Formation, 288 Blanco* Formation, 284, 285 Boquero´n Formation, 189 Boquerones Formation, 189 Bruja Oriental Formation, 259 Bruja* Formation, 62, 63, 207, 212, 219 Bucuey (Santo Domingo, Teneme) Formation, 256 Buenavista Group, 152, 157, 165, 166, 181 Cabacu´ Formation, 291 Cabaiguan* belt intrusives, 139 Cabo Cruz Formation, 288 Cacarajı´cara Formation, 15, 30, 124, 145, 147, 152, 154, 157, 238, 243 Caguaguas* Formation, 16, 61, 114, 119, 120, 138, 139, 151 Caibarien* Formation, 61, 96, 99, 106 Calabazar* Formation, 16, 28, 61, 105, 113, 114, 119– 121, 123, 124, 138 Camaco* Formation, 61, 95, 112, 145 Camajuani* Formation, 61, 121, 123

Capitolio* –Gulf Name ‘‘Cunagua Salt’’ –Informal Name Vin ˜ales –Published Name ‘‘Asiento Viejo Marbles’’, 186 ‘‘Casa-escuela Conglomerate’’, 242 ‘‘Colombo Marbles’’, 187 ‘‘Cunagua salt’’, 25, 41, 91, 92, 103 ‘‘Daguilla amphibolite’’, 187 ‘‘Ferrer Group’’, 285 ‘‘Isla de la Juventud marbles’’, 26 ‘‘Jibacoa olistostrome’’, 242 ‘‘Jojo sequence’’, 265, 266 ‘‘La Reforma calci-siliceous rock’’, 187 ‘‘Las Casas marble’’, 187 ‘‘Loma Quivican sequence’’, 265 ‘‘Los Mangos flysch’’, 242, 243 ‘‘Mal Nombre sequence’’, 265, 266 ‘‘Manacal*’’, 284 ‘‘Mango*’’, 284 ‘‘Marly Micritic Limestone’’ Member, 171 ‘‘Old Volcanics’’*, 26, 62, 63, 217 ‘‘Perdomo*’’, 284 ‘‘Playa Bibijagua marble’’, 186, 187 ‘‘Pre-Camufiro beds’’, 222 ‘‘Purial complex’’, 263, 265, 268 ‘‘Rio Baracoa sequence’’, 263, 266 ‘‘Rio Piedras conglomerate’’, 242 ‘‘Seibabo upper units’’, 209 ‘‘sheeted dikes’’, 26 ‘‘Sierra Chiquita marble’’, 187 ‘‘Sierra de Caballos marbles’’, 187 ‘‘Urria beds’’, 245 ‘‘Via Mulata sequence’’, 263, 265 ‘‘Via Tu´nel conglomerate’’, 242 Agabama* Formation, 62, 212 Agua Santa Formation, 26, 185 Algarrobo crystalline schists, 191 Algarrobos* Formation, 62, 209, 227 Alkazar, 32 Alkazar Formation, 32, 233 Amaro* Formation, 15, 30, 62, 123, 124, 132, 135 Ana* Formation, 139, 182, 233 Ancon Formation, 153 – 165, 171

65

66 / Pardo

Camarones Formation, 289 Camaza´n Formation, 288, 289 Camufiro Formation, 222 Can ˜ada Formation, 185 Can ˜as Formation, 265 Caney Member, 262 Cangrejeras Formation, 283, 284 Cantabria Formation, 208, 213 Capdevila Formation, 32, 233, 235, 236, 237 Capiro Formation, 291 Capitolio Formation, 16, 26, 61, 114, 119, 120, 139, 151, 152, 174 Carlota* Formation, 62, 214, 215, 227 Carmita Formation, 135, 141, 152, 165 Carmita* Formation, 16, 28, 62, 123, 129, 131, 132, 137, 139, 152 Casablanca Group, 27, 28, 101, 105, 106, 111, 112, 120 Casanova* Formation, 62, 211, 219 Castillo de los Indios Formation, 101 Cayo Coco* Formation, 25, 61, 92, 103, 104, 107, 108, 111, 114, 118, 119, 160 Cepeda* Formation, 285 Chafarina Formation, 194, 195 Chambas* Formation, 106 Charcas*Formation, 286 Charco Azul Formation, 191 Charco Redondo Formation, 253, 254, 258 Chirino Formation, 232, 240 Cilindro Formation, 290 Coabilla Formation, 224, 225 Cobre Formation, 23 Cobrito Formation, 26, 189, 191, 193 Cojimar Formation, 280, 283, 284 Collantes Formation, 26, 191 Constancia* Formation, 17, 19, 62, 124, 128, 129, 131, 132, 134, 161, 183 Contrabando* Formation, 61, 105 Corea Formation, 255 Corojo* Formation, 63, 219 Corona*, 62, 123, 129, 130, 132, 133, 136, 202, 203 Corona* Formation, 62, 123, 129, 130, 132, 133, 136, 202, 203 Cotorro* Formation, 62, 63, 208, 212, 213 Cristobal* Formation, 28, 62, 210 Cuabitas Formation, 261 Cumbre Formation, 62, 204, 219, 251 Cumbre* Formation(?), 62, 251 Curamaguey* Formation, 62, 209 Diego* Formation, 63, 211, 212 dikes, 27 Dura´n Formation, 224, 225, 227

El Americano Member, 170 El Jobal Formation, 101 El Sabalo Formation, 18, 150, 164, 181 El Sabalo Formation(?), 18, 150, 160 El Tambor Formation, 191, 193 Embarcadero (Embarcadero Oriental) Formation, 101 Embarcadero Formation, 61, 99, 112, 253 Encanto Formation, 282 Encrucijada Formation, 232 Encrucijada* Member, 62, 129, 131, 132 Escambray* Formation, 62, 212 Falcon* Formation, 63, 221 Farallon Grande Formation, 262 Felicidad greenschists, 192 Felipe* Formation, 62, 208, 213, 219, 227 Ferrer* Formation, 62, 63 Florencia* Formation, 61, 113, 114, 122 Florida Formation, 124 flow breccia member, 62, 215 Fomento* Formation, 63, 217, 219 Francisco Formation, 123, 139, 164, 170, 181 gabbro, 20, 27, 138, 158, 179, 200, 201 gabbros, 125, 160, 175, 200, 205 gabbros G&BW*, 204, 205 Gibara Formation, 100 Gomez* Formation, 22, 43, 62, 132, 207, 213, 219, 225, 227 Gran Tierra Formation, 257, 258 Grande* Formation, 61, 96 granitoids, 164, 175, 200 Guajaibo´n Formation, 143, 145 Guanajay Formation, 281 – 283 Guani* Formation, 61, 95, 102, 114, 118, 119 Guasasa Formation, 18, 19, 126, 150, 161, 173 Guasasa Formation(?)– Pinar-1 deep-water carbonate, 173 Guasasa Formation(?) – Pinar-1 shallow-water carbonate, 173 Guayos* Formation, 218 Guillermo* Formation, 61, 96, 104, 105 Guines Formation, 246 Gu ¨ines Formation, 107 Gu ¨ira de Jauco Formation, 195 Haticos Formation, 252, 253, 257 Hatillo* Formation, 63, 219 Herradura Formation, 189 Hilario* Formation, 62, 208, 213, 227 Hongolosongo Formation, 261 Hoyo Colorado* Formation, 117, 119, 139 Huevero* Formation, 23, 62, 132, 206, 207, 213, 219, 225

Formation Index / 67

Husillo Formation, 282, 283, 284 Iberia Formation, 251 – 254, 256 Infierno Member, 170, 181 intermediate igneous, 199, 201, 204, 205 Isabel* Formation, 63, 218, 227 Jabaco Formation, 281, 282 Jagua Formation, 150, 151, 164, 168, 174, 179 Jagua Vieja Member, 174 Jagu ¨ eyes Formation, 288 Jaguita* Formation, 61, 114, 117, 118 –120, 132, 138 –140 Jaruco Formation, 283 Jatibonico* Formation, 286 Jaula* Formation, 61, 106 Jia Formation, 284 Jicotea Formation, 284 Jimaguayu Formation, 224 Jiquimas* Formation, 62, 215, 224, 227 Jobosi* Formation, 62, 128, 129, 134, 138, 200, 205 Ju´caro Formation, 288 Jucillo* Formation, 63, 218 La Chispa Formation, 192 La Cruz Formation, 291 La Esperanza Formation (Santa Lucı´a Formation), 27, 151, 160 La Farola Formation, 256, 257 La Guira Member, 171 La Jiquima Member, 252, 254 La Legua Member, 171 La Llamagua Formation, 26, 192 La Morena Member, 252, 256 La Sabina Formation, 191 La Sierra Formation, 223 La Trampa Group, 241, 247 La Zarza Member, 149, 150, 151, 161, 164, 165 Lara* Formation, 286 Lesca Formation, 61, 99 Limones Formation, 263 Lindero Member, 282 Llorente* Formation, 285 Loma Blanca Formation, 252 Loma la Gloria Formation, 26, 190 Loma Quivican Formation, 191 Loma Yucatan Member, 223 Los Cayos Member, 153 Lucas Formation, 124, 150 Lucia* Formation, 63, 217, 218 Lutgarda* Formation, 30, 61, 113, 114, 121, 123, 124, 130, 132, 133 Mabujina amphibolite, 188, 190, 193, 204, 266, 267, 327 Mabuya* Formation, 61, 114, 119

Macagua* Formation, 62, 132 Madruga, 233 Madruga Formation, 233 Maguey* Member, 62, 212 Malpaez* Group, 61, 120, 121, 171 Manacas Formation, 31, 32, 102, 125, 138, 141, 146, 157 Manacas Formation, 31, 32, 102, 125, 138, 141, 146, 161, 183 Manzanillo Formation, 263 Maquey Formation, 208 Maraguan Formation, 224 Marti Formation, 223 Martin Mesa Group, 156, 157 Mata* Formation, 28, 62, 120, 123, 129, 171 Matagua´* Formation, 27, 62, 63, 204, 206, 219 Mayajigua* Formation, 30, 61, 95, 96, 101, 102, 105, 106, 111, 112, 114, 115, 121 Mayari Formation, 26, 192 Mercedes, 233 Mercedes Formation, 233 metamorphic exotics, 37, 203 Mı´cara Member, 257 Miguel* Formation, 17, 30, 62, 130, 135, 202 Miranda Formation, 101 Moncada Formation, 171, 175 Monte Alto Formation, 287 Moreno Formation, 152, 153, 165 Naranjo ‘‘Group’’, 192 Narciso Formation, 192 Nazareno Group, 245, 246 Nueva Maria Formation, 17, 26, 27, 135, 150 Obregon* Formation, 206, 213, 214 Orozco Formation, 232 Palenque* Formation, 114 Palma Mocha Member, 261, 263 Palmarito* Member, 212 Palone* Formation, 112, 121 Pan de Azucar Member, 168, 169 Paso Real Formation, 281 Pastora* Group, 208, 212 Pedernales Formation, 288 Pen ˜alver Formation, 153, 232 Pen ˜as Formation, 171, 174 Penton* Group, 119 Perazo* Formation, 285, 286 peridotite, harzburgite (serpentine), 203 Pica Pica, 125, 146, 153, 193 Pica Pica Member, 125, 138, 155, 156 Picota Formation, 257, 258 Piedras* Formation, 277, 278 Pilo´n Member, 262, 263

68 / Pardo

Pimienta Member, 151, 152, 169 Pinalilla Formation, 152 Piragua Formation, 222, 224 Playuela* Formation, 286 Polier (Constancia*) Formation, 124 Polier Formation, 150, 151, 157, 160, 176, 182 Pons Formation, 150, 152, 170, 171, 174 Porphyritic Serpentine, 203 Porphyry Member, 215 Potrerillos*Formation, 217 Principe Member, 245 Provincial Formation, 208, 212 Puerto Boniato Formation, 254, 258 Punta Alegre* Formation, 140 Punta Brava Formation, 245 –247, 249 Puntilla* Formation, 95, 97 Purio Formation, 95, 98 Quin ˜ones Formation, 146, 153, 231, 232 Ramblazo* Formation, 119, 120, 123, 139 Rana* Member, 215 Rancho Bravo Formation, 278 Relampago* Formation, 62, 210 Remedios* Formation, 61, 93, 95, 96, 111, 112, 121, 145 Remedios* Formation(?), 61, 93, 95, 96, 111, 112, 121, 145 reticulate serpentine, 203 Roble Member, 63, 151, 157 Roble* Formation, 221, 227 Rodrigo Formation, 62, 132, 133, 136, 183 Rodrigo* Formation, 62, 132, 133, 136, 183, 202, 227 Rollete* Formation, 285 Romano* Formation, 61, 105 Ronda*, 16, 62, 135, 130 Ronda* Formation, 16, 18, 62, 127, 129, 130, 132 – 136, 174, 196 Rosario Formation, 283 Rosas* Formation, 31, 112, 114, 122, 125, 141 Rosas* Formation, 31, 112, 114, 122, 125, 141 Rubio* Formation, 63, 218 Sabanilla* Formation, 16, 26, 61, 119 – 123, 125, 128 Sagua de Tanamo Formation, 290 Sagua* Formation, 15, 61, 96, 99, 101, 106, 112, 113, 115, 121, 123, 141, 171 Salvador* Formation, 62, 208, 212, 227 San Adrian Formation, 25, 92, 95, 104, 118, 140 San Cayetano Formation, 11, 19, 25, 92, 103, 142, 161, 167, 179, 181, 185 San Francisco Member, 223 San Ignacio Formation, 290 San Juan Group, 191

San Juan y Martinez Formation, 232 San Luis Formation, 278, 288, 289, 290 San Martin* Formation, 31, 61, 96, 99, 101, 113 – 115, 121 – 123, 234 San Pedro Formation, 208, 213 San Vicente Member, 150, 161, 164, 182 Sancti Spiritus granodiorite, 226, 327, 329 Santa Clara* Formation, 32, 63, 209 Santa Teresa Formation, 129, 135, 141, 160, 174 Santa Teresa Formation (Panchita Formation), 160 Santa Teresa*, 4, 28, 44, 62, 139 Santa Teresa* Formation, 19, 28, 62, 132, 136 Santo Domingo Formation, 256 Saramaguacan Formation, 224 Satasa* Formation, 62, 217 Sauco Formation, 192 Seibabo* Formation, 62, 207, 212 Senado Formation, 61, 99, 112, 122 Serpentine, 20, 92, 99, 101, 125, 133, 134, 135, 138, 139, 148, 154, 155, 175, 203, 205 Sevilla Formation, 287 sheeted dikes, 26 Sierra de Rompe sequence, 222 Sierra Verde Formation, 194, 195 Siguaney* Formation, 62, 218, 221 Suceso* Formation, 285 Sumidero (Capitolio*) Formation, 123 Sumidero Member, 150, 151, 161, 165 Taguasco* Formation, 22, 32, 62, 133, 217 Teguaro Formation, 284 Tejas Formation, 259 Teneme Formation, 22, 185 The Guanı´* Formation, 114, 118, 119 Tinajita Member, 252 – 254 Tinguaro Formation, 246 Toledo Member, 245 Tomas* Formation, 286 Trocha* Group, 16, 25, 114, 117 Tumbadero Member, 151, 170 Tumbitas Member, 151, 171 Turiguano* Formation, 106 Turino* Formation, 62, 215, 227 ultrabasic complex, 256 ultrabasics, 30, 251, 253 –259 Universidad Formation, 32, 236, 237, 243 – 246 Vaqueria Formation, 208, 213 Varga* Formation, 285 Vasquez Formation, 280 Vega, 37, 61, 112 Vega Alta Formation, 113, 135, 202 Vega* Formation, 17, 31, 61, 83, 96, 99, 101, 102, 113, 114, 122, 125, 135, 138 – 140, 147, 156, 157

Formation Index / 69

Veloz (Ronda*) Formation, 62, 127, 129, 135 Venega* Formation, 61, 62, 200, 203 Vertientes Formation, 224 Via Blanca Formation, 139, 157, 231, 232, 274 Via Crucis, 243 Via Crucis Formation, 243, 244 Viajaca* Formation, 62, 217 Vibora Group, 233 Vicente* Formation, 63, 229 Vieja Member, 32, 125, 138, 146, 155, 158, 160, 161, 231 Vigia (Vigia Oriental) Formation, 101 Vigia* Formation, 101, 112

Vilato´ Formation, 96 Vin ˜ales Group, 150, 169, 181 Vin ˜as* Group, 26, 42, 61, 94, 95, 97, 98, 101, 104 waxy serpentine, 203, 204 Yaguanabo Formation, 191, 193 Yaguaneque Formation, 256 Yateras Formation, 290 Yaya* Formation, 62, 209, 227 Yayabo Formation, 189 Yayabo* Formation, 286 Yayal Formation, 288, 289 Zacarı´as Member, 169 Zaza* Formation, 218

Localities 1988 GEOLOGIC MAP (PUSHCHAROVSKY ET AL., 1988) GRID LOCATION OF LOCALITIES MENTIONED IN THE TEXT

Coralillo [12-34-54] Cristal, Sierra de Cristales oil field [21-24-72] Cruz Verde oil field [3-36-38] Cubitas, Sierra de [2-21-82] Cumanayagua [12-25-58] Cunagua, Cierra de Judas de la [13-25-76] Cunagua, Loma [13-25-76] Dimas [9-29-16] Escambray massif [20-24-58] [20-22-64] Esmeralda [21-22-79] Florida [21-19-78] Fomento area [12-25-63] Fomento-Taguasco area [12-25-63] [13-24-68] Gibara [23-26-57] Gibara, Silla [23-26-56] Golfo de las Corrientes [17-22-12] Guaimaro [22-14-88] Guaimaro-Las Tunas area [22-14-88] [30-25-49] Guanabacoa [3-36-36] Guanabo oil field [3-37-38] Guanacayabo, Gulf of [30-19-42] Guanajay [10-34-32] Guaney Beach [13-24-80] Guaniguanico, Sierra de [9-26-17] [10-33-29] Guantanamo, Bay [31-15-67] Guasima oil field [3-37-46] Guayabo anticlinorium [12-31-60] Holguin [31-25-56] Iguara´ [13-26-68] Isle of the Pines [18-21-30] Jarahueca [13-25-67] Jarahueca Fenster[13-25-66] [13-26-68] Jardines de la Reina [29-25-25] [29-30-34] Jatibonico [21-23-69] Jatibonico oil field [21-24-69] Jatibonico, Sierra de [13-26-71] La Gabriela [22-20-65] La Habana [3-37-36] Las Mercedes [22-19-84] Las Tunas [30-25-49] Loma de Yeso [13-28-72] Los Barriles [13-25-71] Los Organos, Sierra de [9-27-18] [10-30-24]

Amancio Rodriguez [30-24-42] Ana Maria, Gulf of [21-19-73] Ariguanabo 202 Arroyo Blanco [13-24-69] Asuncion [32-17-77] Bacuranao oil field [3-36-38] Bahia Honda [10-34-27] Baracoa [32-18-74] Batabano [11-32-37] Bauta [10-35-34] Bayamo [30-19-52] Blanquizal [4-36-55] Boca de Jaruco [3-37-39] Boca de Jaruco oil field [3-37-39] Bolivia [13-25-77] Bonachea, Loma [12-29-61] Brisas [3-37-38] Cabaiguan [12-25-65] Cabeza de Horacio [9-28-17] Cajalbana, Sierra de [10-33-24] Calabazar de Sagua [12-31-61] Camaco River [12-29-64] Camaguey [22-17-81] Camajan, Sierra [22-19-84] Camajuani [12-29-63] Camajuani River [12-30-62] Camarioca [3-35-46] Candelaria [22-17-21] Cantel oil field [3-36-46] Cardenas [3-35-47] Cardenas, Bay [3-36-48] Catalina oil field [21-22-68] Cauto [30-21-49] Cayo Coco-Punta Alegre area [13-29-75] [13-27-72] Cayo Frances [13-31-68] Central Depression [21-32-69] Chambas [13-26-71] Chapelin oil field [3-37-47] Ciego de Avila [21-22-73] Cifuentes [12-31-60]

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Los Palacios [10-30-26] Lugaren ˜o [22-19-86] Mamonal oil field [21-23-71] Manati, Bay of [22-16-92] Manicaragua [12-25-60] Mantua [9-27-16] Marbella oil field [3-37-47] Mariel [2-35-31] Martin Mesa Window [10-34-32-] [10-35-33] Mata [12-31-60] Matanzas [3-35-44] Meneses, Sierra de [13-27-68] Mir [30-23-52] Morena, Sierra [12-33-54] Moron [13-25-74] Motembo oil field [12-34-53] Nipe Bay [31-23-61] Nueva Maria quarry [22-19-84] Nuevas Grandes [22-18-91] Nuevitas [22-19-88] Ojo de Agua [21-23-79] Pan de Guajaibo´n [10-23-25] Pen ˜as Altas [3-36-38] Perea-Mayajigua road [13-26-69] Placetas [12-27-63] Placetas [12-27-63] Pons [10-30-20] Pons Valley [10-30-20] Puerto Padre [22-16-95] Punta Alegre [13-28-72] Purial, Sierra del [32-17-72] Quemado de Gu ¨ ines anticlinorium [12-33-57] Rancho Veloz [12-33-56] Ranchuelo [12-28-58] Reforma [21-24-70] Remedios [12-29-64] Rosario, Sierra del [10-32-26] [10-32-29] Sagua la Chica River [12-30-62]

Sagua la Grande [12-33-59] Sagua la Grande River [12-32-59] San Adrian [3-46-32] San Antonio de las Vueltas [12-29-63] San Diego de los Ban ˜os [10-31-25] San German [31-21-58] San Juan de Sagua [10-33-25] Sancti Spiritus [21-23-66] Sancti Spiritus, Alturas de [20-22-64] Santa Clara [12-28-60] Santa Clara, Bahia de [12-34-56] Santa Maria del Mar oil field [3-37-38] Santo Domingo [12-31-57] Santo Domingo-Santa Clara area [12-30-59] [12-28-62] Seibabo syncline, north [12-28-59] [12-27-67] Seibabo syncline, south [12-27-59] [12-26-52] Sierra Madre [30-15-35] [31-15-58] Sitiecito [12-32-29] Taguasco [13-24-67] Tamarindo [13-25-71] Tamarindo-Camajuani area [12-30-62] [13-25-68] Tiguani [31-19-54] Trinidad, Sierra de [20-23-59] Tuinicu fault [12-24-63] Turiguano, Isla de [13-27-74] Varadero [3-36-47] Varadero oil field [3-36-48] Vega [12-30-62] Vega Alta [12-30-62] Vertientes [21-16-79] Via Blanca [3-36-37] Vin ˜as [12-28-65] Vin ˜as River [12-29-65] Yaguayay [13-28-68] Yumuri [3-36-42] Zaza del Medio [21-24-67] Zulueta [12-20-64]

Glossary accumulate in the front of thrusts and become incorporated into the melange. Miogeosyncline The part of a geosyncline devoid of volcanic activity. The sediments can have a continental or pelagic oceanic source. Molasse Sediments derived from the erosion and peneplanation of an inactive orogenic belt. They commonly grade upward from coarse to fine. Nappe A large-amplitude thrust block commonly beginning as a recumbent anticline. The reverse limb is commonly considerably thinned, and sometimes missing, through stretching. It is commonly the result of gravity sliding. Obduction The process by which a slab of oceanic crust rides over the margin of a continental plate. The results of obduction are commonly observed in orogenies, but the mechanism remains obscure. Olistolith Blocks within an olistostrome. Olistostrome Large-scale rock slide consisting of a fine-grained, commonly argillaceous, matrix in which large blocks (from boulder size up to several kilometers) of coherent lithologic units are imbedded. These slides, which are commonly submarine and gravity driven, are normally the result of orogenic uplift. They are sedimentary bodies, but are related to nappes. Orthogeosyncline A broad term that includes the large-scale, linear, sedimentary, and tectonic features characteristic of tectonically and magmatically active continental margins. Subduction The process by which an oceanic plate plunges under a continental or another oceanic plate. A subduction zone Term coined by Bally to describe the leading edge of an orogenic thrust front in which the thrusts are directed toward the continent. B subduction zone Term also coined by Bally to describe the area where subduction of an oceanic plate under a continental plate is occurring; B stands for Benioff. Wildflysch The coarsest conglomeratic upper part of a flysch deposit. Related to and sometimes difficult to differentiate from olistostrome.

Allochthonous Rocks that have been tectonically displaced from their original location of formation. Autochthonous Rocks that have not been tectonically displaced from their original location of formation. Boudinage The stretching process which gives the bedding a link sausage aspect (from ‘‘boudin’’ in French); common in the underside of nappes. CCD Carbonate compensation depth; water depth at which the shells of calcareous planktonic foraminifera are dissolved. Normally 5– 5.5 km (3.1 – 3.4 mi), although a shallower figure is possible because of upwelling. Below this depth, the sediments commonly consist of clays and radiolarian oozes. Eugeosyncline The part of an orthogeosyncline characterized by volcanic activity, generally its oceanic side. Exogeosyncline The continental side of an orthogeosyncline; commonly a basin receiving sediments from both the continent and an active orogeny away from the continent. Flysch Sediments produced by the erosion of an active orogeny where the structural uplift is the continuing source of sediments. A flysch commonly grades upward from fine to coarse. Fragmental Any rock consisting of rock fragments, i.e., fragmental tuff (tuff breccia), fragmental limestone (detrital limestone, limestone breccia), etc. This term has been used frequently in Cuba, and it is commonly difficult to translate written descriptions in more modern terminology such as grainstone, packstone, etc. Geosyncline Any large-scale depression or gradient of the Earth’s crust where sediments tend to accumulate, such as passive continental margins, rifts (taphrogeosynclines), continental interior basins (autogeosynclines), orogenic continental margins (orthogeosynclines), etc. Melange Tectonic mixture of disparate lithologies resulting from the process of subduction or obduction and commonly occurs at great subsurface depth. Strictly tectonic in origin, it can be difficult to differentiate from olistostromes, which commonly

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Pardo, G., 2009, Structural and stratigraphic elements, in G. Pardo, The geology of Cuba: AAPG Studies in Geology Series, no. 58, p. 77 – 83.

Structural and Stratigraphic Elements The generalized geologic map of Cuba (Figure 54) shows that the island is segmented into eight general areas of pre-upper Eocene outcrops surrounded by relatively undisturbed later Tertiary sediments. Although there are similarities between them, each area has its own stratigraphic and structural characteristics. From northeast to southwest, these areas can generally be grouped as follows: (1) north-central sedimentary terranes: from northern Las Villas to northern Oriente; (2) basic igneous-volcanic terranes: from northern Pinar del Rio to eastern Oriente; and (c) southwestern sedimentary terranes: from Pinar del Rio and Isla de la Juventud to southeastern Oriente. These areas are complexly deformed structurally and are present-day topographic highs. They are surrounded by a relatively thin and much less disturbed cover of sediments ranging in age from late lower Eocene to Pleistocene. These areas are large-scale, mostly post-Eocene, uplifts.

middle Eocene are present in a stack of folded and faulted thrusts sheets (nappes) dipping generally to the north. The direction of thrusting is believed to be northward. Along the north coast, near Bahia Honda, ultrabasics and Cretaceous volcanics are present. The general strike is northeast. This area extends into the western Habana Province. 2) Isla de la Juventud area. This consists mostly of a core of relatively low grade, but intensely deformed metamorphics of Middle to Upper Jurassic and possible Cretaceous age, similar to the older part of the section in Pinar Del Rio. This core has the general structure of a dome with the lower metamorphic grades in the center. In contact with the metamorphics, unmetamorphosed Cretaceous volcanics outcrop in the northwestern part of the island.

PRE-UPPER EOCENE

1) Habana-Matanzas area. This consists of Cretaceous volcanics and volcanic-derived sediments, as well as sediments as young as lower–middle Eocene, outcropping in an extremely deformed series of fault blocks. Scattered bodies of ultrabasic rock and some rare outcrops of unmetamorphosed Lower Cretaceous limestones exist. Dips are extremely variable, from horizontal to vertical, and the surface expression of the faults is nearly vertical. However, deep drilling along the north coast has proven that these rocks are structurally underlain by Jurassic and Cretaceous carbonates unrelated to the volcanics. The general strike is west-northwest. 2) Las Villas–northwestern Camaguey area. This area is similar to the Pinar Del Rio area in the sense that

Central Cuba

As already mentioned in the Overview section of this publication under the Regional Setting subsection, in Cuba, essentially, no stratigraphic mixing exists between the continental margin and deep-water marine (miogeosyncline) sediments and the volcanics and volcaniclastics (eugeosycline). In other words, with a few exceptions, all the mixing is of structural origin. Eight major outcrop areas exist as follows.

Western Cuba 1) Pinar Del Rio area. Sediments ranging in age from possibly older than Middle Jurassic to lower –

Copyright n2009 by The American Association of Petroleum Geologists. DOI:10.1306/13141059St583328

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FIGURE 54. Cuba, generalized geologic map. numerous facies of Upper Jurassic to lower–middle Eocene sediments are present. However, although the area is highly fragmented by vertical faults and is complexly folded, the general appearance is that of several long (more than 100 km [62 mi]) southdipping belts. The carbonate sediments are generally found to the northeast, the ultrabasic igneous in the middle, and the Cretaceous volcanics and volcaniclastics in the southwest. The northernmost exposed belt, the Yaguajay belt, shows massive carbonates similar to, and of the same order of thickness, as the Florida – Bahamas banks. The degree of deformation is most intense in the middle, mostly ultrabasic, area, between the carbonates to the north and the volcanics to the south. The general strike is northwest. Near the south coast of Cuba is the massif of Escambray, which consists of an igneous complex and variously metamorphosed, generally low-grade, Jurassic and Cretaceous sediments very similar to the Pinar Del

Rio section. The Escambray massif consists of two nearly circular domes and, as in the Isle of Pines, the metamorphic grade is lowest in their cores. The Las Villas–northwestern Camaguey area has the most complete sequences of sedimentary, volcanic, and igneous rocks occurring in the greatest variety of observable relationships on the island. For this reason, it is used here as a type geologic province and is the basis for many interpretations that will be extended to other parts of the island. 3) Central Camaguey area. This area is similar to the Las Villas – northwestern Camaguey area; however, with the exception of the extensive Cretaceous massive carbonate exposures of the Sierra de Cubitas and a few scattered outcrops of sedimentary facies, most of it is covered by ultrabasic and other igneous and Cretaceous volcanics intruded by large bodies of granodiorite. A steep southwestern dip exists, and the general strike is northwest.

Structural and Stratigraphic Elements / 79

Eastern Cuba 1) Northern Oriente area. This is very similar to the central Camaguey area and consists mostly of ultrabasics and Cretaceous volcanics, with the exception of an area of massive carbonate exposures north and west of Gibara. The dips are very steep toward the south, and the structures trend in a northwest–southeast direction in the west. Toward the east, the strike swings to an east-northeast direction where the sedimentary and volcanic facies, as well as the ultrabasic bodies, strike out to sea between Gibara and the Nipe Bay. Note that the massive carbonate outcrops of Yaguajay in Las Villas, Cubitas in Camaguey, and Gibara in northern Oriente appear to be three large, northwest– southeast en echelon structural highs partially surrounded by and apparently emerging out of an igneous and volcanic terrane. 2) Southeastern Oriente area. This is located south of Nipe Bay and northeast of the Guantanamo depression. Ultrabasic and other igneous rocks as well as Cretaceous to lower Eocene volcanics make up most of the outcrops. In general, they appear less disturbed than in other parts of Cuba; however, in the Sierra del Purial, nearly horizontal thrust sheets of ultrabasics lie on top of Upper Cretaceous volcanics. In Asuncion, in easternmost Cuba, low-grade metamorphics of Jurassic and Cretaceous age outcrop. Again, as with the previously mentioned metamorphics, they exhibit a strong similarity to part of the sedimentary section of Pinar Del Rio. 3) Southwestern Oriente area. Formed by the Sierra Maestra and located south of the Cauto depression, it consists almost entirely of Paleocene and lower – middle Eocene volcanics and volcaniclastics, with associated intrusives and a few Upper Cretaceous volcanics. The pre-upper Eocene rocks will generally be described from north to south and west to east, and the most complete sections will be described first. All the sedimentary sections (miogeosynclinal rocks) will be described together and separately from the basic igneous-volcanic sections (eugeosynclinal rocks).

POST-UPPER EOCENE The eight areas described above emerge topographically from a relatively undeformed late lower Eocene or younger cover that, in places, can reach a thick-

ness of several thousand feet. The areas of younger cover are 1) The northern coast of Habana, Matanzas, Las Villas, and Camaguey 2) Southern Pinar Del Rio, Habana and Matanzas, and the Gulf of Batabano 3) Southeastern Las Villas Central Depression and the Gulf of Ana Maria 4) The Cauto depression and the Gulf of Guacanayabo 5) The Nipe Bay 6) The Guantanamo depression These basins definitely are folded and faulted, but to a much lesser extent than in the pre-upper Eocene rocks. The post-middle Eocene Tertiary sediments will be described according to their geographic areas. In general, the sections consist of classical epiorogenic sediments, although possible time differences exist in the change from flysch to molasse sedimentation between northern and southern Cuba.

DEVELOPMENT OF THE CUBAN STRUCTURAL AND/OR STRATIGRAPHIC NOMENCLATURE The overall regional-stratigraphic history and the structural evolution of Cuba are relatively simple and not unique in the evolution of orogenies and continental margins. However, the position of Cuba on the southern border of the North American continent has been responsible for a complex tectonic history. The Cuban area was successively (1) part of the African and North American craton, (2) a passive margin north of a spreading center with strong left-lateral component, (3) a foreland of what appears to be a subduction zone (with ophiolite obduction in between), and finally, (4) subjected to strong left-lateral shear. This series of events has tectonized the geologic evidence to such an extent that few interpretations are incontrovertible. From 1958 to 1985, there was very little communication between Cuba and the West. However, some of the published information that filtered out in the last 30 yr is of outstanding quality, such as the works by Milla´n and Somin (1975, 1976, 1981, 1985a, b) on the metamorphics, those by Piotrowska (1986a, b, 1987a) and Pszczo´lkowski (1985, 1987) in Pinar Del Rio and Matanzas, and Iturralde-Vinent (1969, 1970, 1972, 1975a, b, 1977, 1981, 1985, 1996, 1998) in general geology. These authors have used western stratigraphic nomenclature and their work is easily interpretable.

80 / Pardo

Unfortunately, much other information follows Sovietera practice of naming rocks by age and interpretive basin classification, such as ‘‘Cretaceous parautochthonous miogeosynclinal,’’ which makes correlation with simple lithostratigraphic units difficult. In a few cases, the Cuban published information appears erroneous when compared to the solidly established pre-1960 data. Therefore, some of the recent information, when added to the natural geological complexities, increases the problems of interpretation. It has to be mentioned that the Mapa Geologico de la Republica de Cuba (Pushcharovsky et al., 1988), on data collected up to November 1, 1985, is the best overall published source of information available yet. Another excellent publication is the Mapa Tectonico de Cuba (Pushcharovsky et al., 1989).

Gulf’s Stratigraphic Nomenclature When Cuban Gulf Oil initiated systematic geologic mapping of central Cuba in 1951 at the scale of 1:40,000, the confusion over preexisting terminology was such that it was decided to establish a framework of stratigraphic units as if the geology of the island was totally unknown. Conventional rules of stratigraphic nomenclature were strictly adhered to; any association of rocks with characteristic and recognizable lithologic features were given a formation name. The age was determined through fossils or stratigraphic relationships and had no effect on the lithostratigraphic terminology. The number of formations thus described by the Cuban Gulf Oil was quite large, on the order of 125 for the pre-upper Eocene in central Cuba. With the extreme structural complexities, many groups of outcrops had recognizable characteristics, but were totally disconnected from each other, so that their relationships could not easily be determined in the field. In addition, to avoid misgrouping, it was deemed necessary to separate related lithologies that, under less extreme circumstances, might have been given a member rank and grouped under one formation name. In addition, the extreme structural shortening juxtaposes many lithologies that normally would be spread across a large area. It can be said that the large number of recognizable lithologic units across such a relatively small area is a measure of the magnitude of the telescoping of the basin. It should be emphasized that many of the stratigraphic units that have been published in the recent literature, notably in Pinar Del Rio and in the metamorphic massifs, are well defined and follow accepted international guide-

lines of stratigraphic nomenclature (Hedberg, 1976; Salvador, 1994).

The Belt Nomenclature Problem Several important related terms have been widely used in Cuba throughout the last 39 yr. These are belts, facies-structural zones, structurofacies zones, zones, tectonostratigraphic units, tectonic units, tecto-units, etc. The fact that in central Cuba, the names of these so-called units, zones, or belts have been freely interchanged by different authors increases the confusion considerably. For instance, the Las Villas unit of Hatten is approximately Pardo’s Cifuentes and Placetas belts, whereas Pardo’s Las Villas and Sagua la Chica belts are (more or less) Hatten’s Zulueta unit; Ducloz’s Remedios zone is Pardo’s Yaguajay, Jatibonico, and Cayo Coco belts or Hatten’s Remedios and Cayo Coco units; and so forth. Figure 55 is a chart showing the terms that have been most commonly used in central Cuba. What follows is an attempt to explain the origin and the reason for such terminology and the ensuing confusion. Although the complexity of the pre-Tertiary geology of Cuba has long been known (DeGolyer, 1918), Rutten, in 1936, recognized that, broadly speaking, the Las Villas Province could be divided into two terranes: limestone to the north and igneous-volcanic to the south. In 1937, a Cuban geologist, Ortega y Ros, properly identified, described, and named many of the Jurassic, Cretaceous, and Paleogene stratigraphic units of central Cuba. Unfortunately, his work appeared in an obscure publication and remained unnoticed until the middle 1950s. By the late 1940s, the two-terrane scheme had been further refined by various geologists, and the standard subdivisions of central Cuba became massive Remedios carbonates to the north, serpentine and Tuff series to the south, and the radiolarian-rich, thin-bedded, siliceous Aptychus Limestone in between. As Cuban Gulf Oil initiated the geologic mapping that began with the pre-upper Eocene of central Cuba, it became apparent that certain areas were characterized by successions and associations of lithologies quite different from those in adjoining areas, although the ages represented were similar. Because these areas tended to be elongated along the strike, they were named ‘‘belts.’’ They were strictly informal operational subdivisions. In 1953, Pardo (Cuban Gulf’s Memorandum 92, p. 4) wrote the following: Northern Las Villas and northwestern Camaguey can be subdivided in several parallel northwest,

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FIGURE 55. Central Cuba nomenclature.

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southeast trending belts. Each one of these is characterized by its structure and stratigraphy. . . In 1954, Pardo (p. 5) modified this definition as follows (the definition was published for the first time in Pardo, 1975, p. 561): The concept of belts exposed in G. Pardo memorandum no. 92 (1953) has remained essentially unchanged; however, due to the complexity of the tectonics, many of the belts cannot be geographically separated onto continuous areas. They are in many instances scattered in small patches following certain general trends. Therefore, for many of the belts, it is impossible to define them as a geographic unit such as the Yaguajay or Las Villas belts (which are continuous), and one has to recur to a stratigraphic definition of the belt; that is, a belt will be defined as an association of several lithologies that occur invariably together. This definition can be carried even further in a paleogeographic and paleotectonic sense: every part of a belt will have had an identical succession of tectonic, sedimentary and igneous events during geologic time. It turned out that some belts have characteristic internal structure. Lithologic associations are commonly bounded by faults, but they also grade into one another (or at least are not separated from each other by obvious major faults), making the assignment of lithologies to belts difficult (facies do eventually change). In Cuba, faults are everywhere, and they can be strongly deformed, so their importance is difficult to judge from field mapping alone. The disparity between two adjacent belts was used to determine the probable magnitude of a fault and not the magnitude of the fault to define the belt. In addition, the boundary faults are commonly imbricated with components of the two adjacent belts repeated several times. The California Company (Chevron) initiated reconnaissance work in 1951 and, in 1957, began their systematic mapping of central Cuba. Of course, they had no access to Gulf reports and, in 1957, formalized a classification scheme, like Gulf’s belts, called ‘‘tectounits,’’ but differing from Gulf’s by being slanted more heavily toward the present structure instead of stratigraphy. In 1957, in a private California Company report, Meyerhoff and Hatten wrote the following: A tecto-unit is defined as a large and essentially discrete structural unit, bounded on its two long

sides by a tectonic feature (such as a fault system), and characterized by unique petrology. A tectounit generally parallels regional stratigraphic strike. The characteristic of the petrology and stratigraphy in each tecto-unit are distinct. . . As can be seen, the differences between the Gulf and California Co. definitions are not major, but there were strong differences of opinion relative to the assignment of some rocks to equivalent belts (units). In 1960, the files of all foreign oil companies were confiscated by the revolutionary government, and the above concepts became public knowledge in the geologic circles of Cuba and of the assisting Soviet block countries; however, they remained virtually unknown in the west, where essentially nothing was published until the late 1960s to mid-1970s. Meanwhile, in Cuba, the application of these definitions, with varying degrees of understanding, resulted in confusion. For example, Dilla and Garcia (1984, 1985) reshuffled the existing terminology and split the existing zones, units, etc., between the Cretaceous and the Paleocene. They created two new zones (Sagua and Cabaiguan) that they thought contained only flysch sediments superimposed on the older rocks of all other zones. This reduced the usefulness of previously recognized zones, units, and belts, and using names that had been previously published added to the existing confusion. Besides, their assumption that flysch sedimentation always and only occurred from the Paleocene to the middle Eocene is surely not correct. In Pushcharovsky et al. (1988), these belts, units, zones, etc., are referred to as ‘‘zonas estructurofaciales’’ or structurofacies zones.

General Remarks The Gulf data set forms a coherent package, with well-established stratigraphic definitions now in the public domain, and its nomenclature is used as a backbone for this publication. A significant reason to do so is that the author of this publication knows precisely the meaning of the Gulf names whereas much of what has been published later has ambiguous definitions. As will be seen, many Gulf names have been incorporated in today’s official nomenclature or published literature, but are not so credited. In some cases, credit is given to the author of the Gulf name, i.e., Wassall, Truitt, etc., who were Gulf employees, but interestingly enough, Gulf is never recognized; nor is any other capitalist organization for that matter. As a result, it is not always known whether the presently

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used Gulf names are the result of a coincidence (i.e., same type locality), or whether they found their way into the terminology from Gulf’s early reports and were sometimes given a somewhat different connotation. This is also true of the work of other companies such as Chevron, Shell, etc. However, credit should be given to many Cuban and Eastern European workers who made definite efforts to identify the original author of many stratigraphic units. If the political situation had been different, much confusion would have been avoided. No attempt will be made to identify the author of Gulf’s terminology. It was a cooperative effort involving P. Bronnimann, G. Pardo, P. B. Truitt, and H. Wassall. Truitt and Wassall conducted most of the fieldwork and were the originators of much of the terminology (full references can be found in the University of Texas copies of Gulf’s reports). In some cases, Gulf used already existing names and applied a precise definition that might not have been followed by other authors. In this publication, all the names defined and used by Gulf will be followed by an asterisk (*), for example, to differentiate the Vega* Formation as defined by Gulf from the Vega Formation as used in Pushcharovsky et al. (1988), or Gulf’s Las Villas* belt from Hatten et al.’s Las Villas unit. It is hoped that in this manner, confusion will be avoided. At any rate, these homonyms will be clarified in the text. There certainly will be some departures from original definitions and interpretations because of new information such as age dating, published studies on the metamorphics, deep drilling, new geologic concepts, etc. Of course, in areas where other sources give more complete information, such as Pinar Del Rio, Cama-

guey, and Oriente, the published names will be used, and an attempt will be made to correlate them with Gulf’s data when pertinent. An attempt will be made to always give credit where it is due, but this sometimes will be impossible, considering the large volume of unpublished material that is being consulted (Gulf’s and others). However, the primary purpose of this chapter is to give information about Cuba and not to describe all the arguments that have ensued ever since the second geologist visited the island. The Geologic Map of Cuba, scale 1:250,000, (Pushcharovsky et al., 1988), and the Tectonic Map of Cuba, scale 1:500,000, (Pushcharovsky et al., 1989), published jointly by the Academy of Sciences of Cuba and the Academy of Sciences of the former Soviet Union will be extensively used to provide uniformity in discussing the entire island. To assist the reader, a table has been prepared (the Localities section of this publication) where the approximate location of geographic localities mentioned in the text is given, using the 10  10-km (6  6-mi) grid system on the 1988 geologic map (Pushcharovsky et al., 1988). This grid has an arbitrary origin west and south of Cuba, and the grid number refers to 10,000 m (33,000 ft); for instance, 33N means 330,000 m (1,082,677 ft) north of the origin. It should be noted that the southern part of Oriente has a different origin than most of the island (the usual problem of trying to fit a square grid over a sphere). In the Localities section of this publication, the southwestern corner of the quadrangle in which the locality is situated will be identified in the following manner: The locality name will be followed by [sheet number — grid north — grid east]. For instance: Quemado de Guines anticlinorium [12-33-37].

2

Pardo, G., 2009, Pre – Upper Eocene stratigraphy, in G. Pardo, The geology of Cuba: AAPG Studies in Geology Series, no. 58, p. 85 – 275.

Pre–Upper Eocene Stratigraphy INTRODUCTION

cross section across the former orthogeosyncline. By qualitative, I mean that the abundant evidence of large thrust and transcurrent displacements, which, together with the scarcity of facies changes along the strike of the belts, make the reconstruction of an accurate paleogeography difficult. Along much of the axis of the island, the structural complexities are extreme. For instance, in one of the less disturbed areas, a section being measured appeared to consist of an interbedding of more than half a dozen 1-ft (0.3-m) beds of manganese-stained limestone, consisting entirely of rudist fragments, and thin-bedded fine-grained limestones; very detailed mapping revealed that there was only one bed of rudist limestone repeated many times by isoclinal folding. Extreme boudinage is common. In one case, all the components of a Lower Cretaceous to lower–middle Eocene section, normally more than 4000 ft (1200 m) thick, were present in an outcrop not more than 300 ft (90 m) thick. In much of the outcrops, dip and strike mapping is totally meaningless because the different lithologic units are commonly present as isolated blocks. Blocks of similar lithologies, although disconnected, follow some general mappable trend, much as would be expected in landslides or olistostromes. Many of these areas, mapped by Gulf in detail, have been lumped by recent Cuban surveys into a stratigraphic unit called Vega Alta and defined as an olistostrome. Concerning well nomenclature, wells drilled prior to 1959 will be named by company name (i.e., Texaco, Gulf, etc.), lease name at the time of drilling (Cayo Coco, Blanquizal III, etc.), and well number. Later wells will be named by the organization responsible for the drilling (ICRM, EPEP, etc.) and the well name. In relation to well data, attention should be called to the fact that because of structural complications and the nature of the rocks (especially in the carbonate areas), the only way that sections can be accurately

In this section, only the stratigraphy of the rocks deposited before and during the violent events of the Cuban orogeny will be described. The deformation probably reached its peak during the early–middle Eocene. The reason for this rather indefinite time assignment is that no index faunas have been found to separate the middle from the lower Eocene in the synorogenic flysch sediments, much less in the wildflysch that characterizes the culmination of the orogeny. The only evidence that the orogeny is pre – upper Eocene is a widespread, well-defined unconformity below an upper Eocene orbitoid-rich limestone that, although occasionally deformed, was not involved in the strong orogenic tectonism. As will be seen later, the tectonic events that marked the end of the orogeny were not exactly synchronous all over Cuba. In the south, the orogenic deformation started in the late Maastrichtian to Paleocene, whereas in the north, the deformation started in the early Eocene. The molasse (or erosion of already inactive topography) cycle started in the south in the early Eocene while thrusting proceeded in the north in the middle Eocene with the production of associated flysch deposits (or erosion of an active orogenic front). The molasse was carried piggyback by the northward advancing thrusts while contemporaneous flysch was being generated in the north. Stratigraphy and structure are intimately intertwined in Cuba; the significance of structural features can be understood only through the knowledge of stratigraphy. Therefore, in this chapter, the stratigraphy will be described first to establish a plausible preorogenic paleogeography. As previously mentioned, many outcrops of related lithologies tend to be grouped in long, linear belts, permitting the reconstruction of a qualitative

Copyright n2009 by The American Association of Petroleum Geologists. DOI:10.1306/13141061St583328

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FIGURE 56. Lithologic symbols. identified and correlated in the subsurface is through continuous coring. Identification by cuttings is difficult and ambiguous because of the large amount of natural reworking in many of the sections, and geophysical logs do not differentiate the subtle differences between the many stratigraphic units that commonly can only be identified through microfacies analysis in thin sections. This is important because the lithologic data available today outside of Cuba consist mostly of cuttings. It is not known what kind of data forms the basis for most of the currently published identifications. The descriptions of fossiliferous stratigraphic units will contain a faunal list. Whenever possible, genera and species will be given. In many cases, the genus is followed by ‘‘sp.’’ or ‘‘spp.’’ Paul Bro ¨ nnimann had established an extensive type collection where, according to the common practice of many oil companies, numbers identified the species, such as, Dicyclina 2, Globotruncana 5, etc. These were cross-indexed to formal species names. Unfortunately, the type collection remained in Cuba, and as of this date, its fate is unknown. In many of the reports, only the informal species number is available. Because this number is of

no use to the readers of this study, it is replaced by ‘‘sp.’’ or ‘‘spp.’’ Even without species names, the faunal composition is of interest. The stratigraphic descriptions are accompanied by a graphic columnar section. In most cases, the thicknesses given in Gulf Oil (Gulf) data (formation name followed by an asterisk) were measured in the field or in wells. Where measurements were impossible because of structural complications, thickness estimates only will be given. When the thicknesses are from the literature, it is not always possible to know whether they are estimates or measurements. For convenience, the pre–upper Eocene graphic columnar sections will show a scale in meters and feet with the origin at the top of the Lower Cretaceous. The post–middle Eocene columnar sections show the measurements from the base of the upper Eocene. Figure 56 shows the lithologic symbols used throughout the study unless otherwise noted in the figures. Cuba can be subdivided into the following major geologic provinces: 1) The north-central terrane. It extends along the north coast from the subsurface between Habana and

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FIGURE 57. Central Cuba sedimentary terranes: generalized geologic map. Matanzas to Gibara in Oriente and is best developed in central Cuba. It consists of sediments deposited along the southern margin of the North American continent. This terrane can be further subdivided into a. Jurassic – Cretaceous carbonate platform b. Cretaceous carbonate slope or scarp c. Jurassic platform to Cretaceous deep-water limestone and chert basin These provinces have been further subdivided into belts. The structure varies from reverse faults and south-dipping monoclines to complexly folded and faulted, northward-directed thrust faults. 2) The southwestern terrane. It has been recognized from the subsurface of the Guanacahibes peninsula in Pinar del Rio to the Escambray massif. This terrane can be subdivided into an unmetamorphosed phase in the Guaniguanico Mountains, and a metamorphic phase extending from the Cangre through the Isla de la Juventud and the Escambray massif. In southeastern Oriente, in an area called Asuncion, are some metamorphosed sediments showing strong affinities with the La

Esperanza belt of Pinar del Rio, and the Cifuentes* belt of central Cuba. The oldest Jurassic consists of a thick quartzose terrigenous section overlain by Late Jurassic to Early Cretaceous bank carbonates that grade south and upward into a deep-water limestone and chert section similar to the north-central terrane deepwater facies. In the Guaniguanico Mountains, the structure consists of a succession of north-dipping thrust sheets. The Isla de la Juventud and the Escambray massif are domal structures showing stacks of thrust sheets. 3) The basic igneous-volcanic terrane. This terrane extends along the axis of the island and forms a complex syncline from Bahia Honda to Oriente that today separates the north-central terrane from the southwestern terrane. The contacts between the three terranes are always of a tectonic nature. This terrane can be subdivided into a lower basic igneous sequence and an upper volcanic arc sequence. The structure and stratigraphy of this terrane can be quite complex, showing stacks of folded thrust faults and a high variety of volcanic types.

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FIGURE 58. Eastern Cuba sedimentary terranes: generalized geologic map.

A lingering question has been whether the southwestern terrane was directly in contact with, and therefore part of, the deep-water part of the northcentral terrane, or if it was separated from it by the basic igneous-volcanic terrane. It must be emphasized that, with very few exceptions, rocks of the basic igneous-volcanic terrane are never found in normal sedimentary or intrusive contact with any of the components of the sedimentary provinces. Furthermore, no basic igneous and volcanic detritus is present in these sedimentary belts before the very Late Cretaceous or early Tertiary. This suggests that the basic igneous-volcanic terrane is completely exotic and was tectonically emplaced over the other two terranes. The stratigraphy of these provinces will be described from north to south and west to east. However, as will be seen later, the definition of belts (also referred to as Hatten-Meyerhoff units, Hatten et al., 1958) given in this chapter does not fit part of the carbonate platform, and to some extent, the entire basic igneousvolcanic terrane is a belt in itself. The major subdivisions of the Cuban geology given in this study will be flexible and will be named ‘‘belt’’ only when the definitions are satisfied. In the following discussion, the nomenclature of the major faults will follow the original nomenclature. Specifically, the faults are named for the belt of which they form the northern (upthrown) boundary. When consulting the literature, this can cause confusion because other authors have used the same names to designate other faults. For instance, the

Hatten et al. (1988) Las Villas fault is quite different from the Las Villas* fault used in this study.

NORTH-CENTRAL TERRANE LAS VILLAS: NORTHERN ORIENTE Under this section heading will be grouped all the sedimentary rocks (nonvolcanic) found outcropping and in the subsurface in central and northern Cuba that is extending from Habana to Gibara in northern Oriente. Figures 57 and 58 show the general distribution of the north-central and southwestern terranes and most of their subdivisions in central and eastern Cuba. Figure 59 is a general correlation chart for the northcentral terrane arranged according to belts and areas. As will be seen later, these outcrops can be restored to a normal succession of facies typical of a continental margin, going from shallow bank carbonates to a deep, pelagic oceanic environment.

Jurassic–Cretaceous Carbonate Platform The carbonate platform province was characterized by the deposition of thick platform carbonates and local evaporites during the Late Jurassic and Early Cretaceous. Locally, the carbonate bank sedimentation continued uninterruptedly through the Late Cretaceous and Cenozoic much as in the Bahamas Bank. This is generally known as the Remedios zone (Ducloz and Vaugnat, 1962). This name will not be used in this publication because (1) it includes the Sagua

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FIGURE 59. Correlation chart, north-central terrane, central and eastern Cuba.

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FIGURE 60. Central Cuba, basal section.

la Chica* and Jatibonico* belts that are not part of it and (2) it has been given different connotations by other authors. In Cuba, the most complete sections are known from the outcrops of the Yaguajay* belt. This is an uninterrupted south-dipping monocline with very good exposures and relatively little faulting. The Instituto Cubano de Recursos Minerales’ (ICRM) wells and Gulf Blanquizal III-1 have contributed additional but, unfortunately, incomplete knowledge of the area, and Shell Cayo Coco-2, although it provided excellent information, is representative of somewhat different conditions. Consequently, in this province, the description of the stratigraphy will not proceed from north to south, but from the Yaguajay* belt–type section north and south to other areas. The lower part of the section has never been observed in situ in surface exposures or in wells, but something can be inferred from the outcrops of three diapir complexes at Loma de Yeso, Isla de Turiguano, and San Adrian (the Loma Cunagua diapir shows only young Tertiary sediments on the surface). The drilling of Kewanee Collazo-1 in Loma de Yeso, Kewanee Tina-1 and Kewanee Tina-2 in Loma Cunagua, and geophysical data also contributed some information. As will be seen later, the fragmentary information on the lower

part of the section suggests that an older sequence could possibly underlie much of the carbonate platform province. It could also underlie, or at one time have underlain, other provinces or belts, as indicated by the San Adrian diapir, which is surrounded by rocks from the basic igneous-volcanic province. In view of its possible widespread occurrence, this basal section will be discussed first.

Basal Section A fundamental question revolves around the total thickness of sediments that can be expected under the carbonate platform. Gulf’s depth estimates to magnetic basement, made during the early 1950s, based on a survey by AeroService Corp. along the northeast coast of Cuba, Cay Sal, and southern Bahamas, range between 30,000 and 40,000 ft (9000 and 12,000 m). In the Cayo Coco area, the depth to magnetic basement is on the order of 30,000 ft (9000 m). Some old reflection seismic, by Shell in the Cayo Coco area, suggests a minimum depth of 20,000 ft (6000 m). Deep crustal seismic measurements by the Soviets have given 41,000 ft (12,500 m) in Cayo Fragoso and 36,000 ft (11,000 m) in Chambas (Scherbakova et al., 1978a). See Figure 60 for localities.

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The deepest wells drilled in the area are Tenneco Doubloon Saxon-1 to 21,740 ft (6628 m) and GulfCalifornia Cay Sal-1 to 18,906 ft (5764 m) in the Bahamas, 30 and 75 km (18 and 46 mi), respectively, north of the Cuban coast. In the north coast of Cuba, the deep wells drilled are ICRM Cayo Fragoso-1 to 16,450 ft (5014 m), ICRM Cayo Frances-5 to 14,885 ft (4537 m), ICRM Cayo Romano-1 to 13,317 ft (4060 m), Gulf Blanquizal III-1 to 11,218 ft (3419 m), and Shell Cayo Coco-2 to 10,563 ft (3220 m). None of them reached basement. At least 10,000 ft (3000 m) of unknown section obviously exist. An additional problem is that the deep structure of the coastal area is poorly known, and no data have been published by ICRM. For instance, some information (Shein et al., 1984; Petroconsultants, 1989, personal communication) suggests that much of the coastal area of Cuba, where the deep wells have been drilled, could be the upthrown block of a large reverse fault, or system of faults, approximately paralleling the coast. It could have as much as 10,000 ft (3000 m) of repeat. If this were the case, the unknown stratigraphic thickness could be less than 10,000 ft (3000 m). Based on the exposures in the diapirs and the drilling of Kewanee Collazo-1, Kewanee Tina-1, and Kewanee Tina-2, three lithostratigraphic units have been established: the informal Cunagua salt, the Punta Alegre* Formation, and the San Adrian Formation.

Cunagua Salt The name is derived from Loma Cunagua, where the well Kewanee Tina-1 drilled through a section of evaporites from 5508 to 10,526 ft (1679 to 3209 m). Halite forms as much as 70% of the section. It contains red and maroon shales, very finely crystalline white anhydrite, brown dolomite, white to orange limestone, and traces of red chert. No gypsum is present. In the Kewanee Collazo-1 well drilled in Loma de Yeso diapir, some halite was encountered at 1420 ft (433 m) and became a dominant component at 1700 ft (518 m). 1700 – 3100 ft (518 –945 m): The section consists of fairly massive and pure halite (in average more than 50%), containing many inclusions of anhydrite and dolomite. 3100–3963 ft (945–1208 m): The section consists of halite, possibly containing many inclusions of anhydrite, dolomite, and argillaceous silt. According to Calvache (1958), the salt has impurities fragments, pebbles, and masses of soft silt and

anhydrite, that in general have a tendency to be horizontally aligned. The salt crystals, where seen, are horizontal. On a core of silt, there are horizontal bands of pure salt. There is nothing in the salt suggestive of ‘‘Salt Dome Conditions’’ as vertical flowage, or vertical orientation of impurities, unless it represents an ‘‘overhang’’. The Cunagua salt is believed to stratigraphically underlie the Punta Alegre* Formation, although in Kewanee Collazo-1, the contact is structurally disturbed. No direct evidence of the age of the salt exists, but spores in the red shales included in the halite gave an age of middle Mesozoic, probably Middle Jurassic. It is considered equivalent to the Louann Salt by many authors. The geographic extent of the Cunagua salt is unknown. Salt water has been reported in wells drilled near the San Adrian diapirs in the Yumuri Valley in Matanzas. Other diapirs have been reported from seismic surveys in deep waters north of Cuba, but their composition is unknown.

Punta Alegre* Formation This unit, named by Truitt (1956b), has its type locality at the Loma de Yeso diapir and outcrops in the Isla de Turiguano diapir, both near the town of Punta Alegre. These diapirs are surrounded by younger Tertiary sediments and are located to the northeast of the carbonate platform outcrops of the Yaguajay* belt. This is different from Meyerhoff and Hatten’s (1968) Punta Alegre Formation. It must be emphasized that halite is not included in Truitt’s original definition of the Punta Alegre* Formation, which consists only of exotics (many of them from rocks never observed before) in a gypsum matrix. The formation name applies to a breccia of heterogeneous rock fragments in a gypsum matrix. The breccia has been subdivided into four types based on the number, size, and abundance of exotics and the red, blue, yellow, and brown color of the gypsum matrix. The exotics form most of the rock and vary in size from a few centimeters to more than 100 m (330 ft). They consist mostly of (1) blocks of black, dark-gray, and dark-red medium-grained limestone, sometimes oolitic; (2) dolomitized limestones and dolomites, (3) purple slate, (4) red shale, (5) argillite, (6) blue quartz sedimentary quartzite, (7) quartz sandstone, and (8) tuffs. The carbonates form most of the clasts. The age of the Punta Alegre* Formation is considered Tithonian or older based on abundant Favreina joukowskyi that is found in the dolomite exotics. Because of Favreina joukowskyi’s importance as an Upper Jurassic fossil (it is the only identifiable fossil

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found in the Punta Alegre Formation), it is worth mentioning the remarks of Bro ¨ nnimann (1956, p. 9), where he discusses its recorded worldwide occurrence. He concludes that From these records it appears that Favreina is a facies fossil of rather long range (Upper Jurassic to Tertiary). However, in Cuba and Trinidad, B.W.I., possibly also Mexico, it seems characteristic of a facies, which apparently is restricted to the Upper Jurassic (Oxfordian – Tithonian). . .. Faunistically therefore, the Upper Jurassic age of the Punta Alegre* Formation may still be questioned, but it is most probable that lithology and Favreina indicates here, as it does elsewhere in Cuba, an Upper Jurassic age. Kewanee Collazo-1 was spudded in the Loma de Yeso diapir 45 ft (13 m) above the Punta Alegre* Formation and encountered the following section: 45 – 630 ft (14 – 192 m): This consists of a mixture of gypsum, limestone, and dolomite, similar to the one in the outcrop. 630 – 1700 ft (192 – 518 m): The gypsum is increasingly replaced by anhydrite, and halite appears at 1420 ft (433 m). Below 1700 ft (518 m) to total depth at 13,032 ft (3972 m): Halite becomes common to dominant. Meyerhoff and Hatten (1968) proposed that the Kewanee Collazo-1 section, including the Cunagua salt, from 45 to 3963 ft (14 to 1208 m) be designated as the type section of the Punta Alegre Formation (for the first time in print). In view of the tectonic complications, the original Truitt definition will be maintained in this study. A question remains as to whether the gypsum at Punta Alegre and Isla de Turiguano has a cap rock origin by solution of halite (Meyerhoff and Hatten, 1968) or, as will be seen later, is derived from the anhydrite that is commonly interbedded with Lower Cretaceous and Upper Jurassic dolomites of the Cayo Coco* Formation. Halite is certainly overlain by gypsum at Loma de Yeso, but at Loma Cunagua, only halite containing some anhydrite, with no gypsum, is present. It is therefore possible that the Punta Alegre Formation of Meyerhoff and Hatten consists of a tectonic mixture of two or more stratigraphic units, the Punta Alegre* Formation, possibly equivalent to part of the Cayo Coco* Formation (that will be described later) and the Cunagua salt unit, which is dominant-

ly halite, with subordinate shale, siltstone, dolomite, and anhydrite. To consider the Punta Alegre and Isla de Turiguano diapirs similar to the Gulf Coast salt domes is misleading. They are associated with the upthrown limbs of large south-dipping Oligocene or later thrust faults.

San Adrian Formation This formation, initially described by Flores (1949) and formally named by Ducloz (1960), outcrops in a cluster of four fault-associated diapirs close to San Adrian, near the town of Matanzas. Compared to the diapirs near Punta Alegre, in the carbonate coastal province, these are surrounded by the basic igneousvolcanic province. As in Loma de Yeso, the formation name applies to a breccia of heterogeneous rock fragments in a gypsum matrix. The breccia contains abundant components up to 12 ft (4 m) in size. These components consist of (1) light- to dark-gray, silty and finely sandy, micaceous, slightly calcareous shales; (2) well-indurated medium-gray, coarse- to fine-grained, quartz sandstone with occasional feldspars and mica; (3) beige fine-grained limestone; (4) gray Nannoconus limestone; (5) fine-grained limestone with quartz grains; (6) dark-gray, fine-grained, thin-bedded radiolaria limestones; (7) dolomitic limestones; (8) marble; and (9) quartz mica schists. Sandstones and shales form most of the exotics, and a large inclusion of serpentine exists. Piotrowski and de Albear (1986) consider the major part of the diapirs to be a clastic-carbonate-evaporite sequence that has been fragmented by diapiric evaporite flowage. A minor part of the diapirs contains exotic blocks, from totally different environments, dragged from the overlying country rock such as the Neocomian Nannoconus limestones and serpentine. Furthermore, the clastic components are very similar to those outcropping 300–400 km (186–248 mi) to the west as part of the San Cayetano Formation that will be described below. Salt has not been observed in the area, but salt water has been reported in some of the water wells drilled in the vicinity. The age of the San Adrian Formation is considered Upper Jurassic (not later than Neocomian). It is believed to represent an evaporitic section, equivalent to the Punta Alegre* Formation, but with a much higher percentage of sandstones and shales. Here, like in the Punta Alegre area, the diapirs consist of material flowing along faults cutting a large variety of terranes.

Basal Section Discussion The above is definite evidence that a poorly known section at the base of the carbonate platform exists.

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FIGURE 61. Central Cuba, Yaguajay* belt. In the Punta Alegre area, the large percentage and types of carbonates compared to the clastics suggest a relationship between the evaporites and the bank carbonates. However, some clastics appear to be related to the San Cayetano. Other clastics are totally unrelated to anything known in Cuba and suggest the Permian micaceous black shales and blue quartzites of the Maya Mountains in Belize. By contrast, in San Adrian, the great abundance of the San Cayetano-like clastics suggests that here, the evaporites were mostly interbedded with them. Although some carbonates are present, many of the exotics appear to belong to belts that structurally overlie the evaporites (Las Villas*, Cifuentes*, etc.), and few of them suggest the platform carbonates. This, together with the fact that none of the wells drilled west of Gulf Blanquizal III-1 encountered the continuous platform facies, indicates that the edge of the platform must be somewhere between Gulf Blanquizal III-1 and Cardenas Bay. However, the evaporites must have existed, interbedded with the San Cayetano, under the Las Villas* belt. Other diapirs have been reported in deep waters north of Cuba, but none has been confirmed.

Yaguajay* Belt In 1975, Pardo extended the meaning of the Yaguajay* belt to all the carbonate platform outcrop areas, including the Sierra de Cubitas in northern Camaguey and the Gibara area in northern Oriente. See Figure 61 for locations in central Cuba.

This area is parallel to the coastal province and is limited to the south by a line running approximately through south of Sagua la Grande, San Antonio de las Vueltas, Vin ˜as, the southern part of the Sierra de Bamburanao and Sierra de Meneses, and northern the eastern end of the Sierra de Jatibonico. This belt is poorly exposed west of San Antonio de las Vueltas. This area is part of the Remedios (1) structurofacies zone of Pushcharovsky et al. (1988). This belt is approximately equivalent to the Remedios unit of Hatten et al. (1988), but not the original Remedios zone of Ducloz and Vaugnat (1962) that included the entire coastal area. In the geologic map of Cuba by Pushcharovsky et al. (1988), a Remedios ‘‘structurofacies zone’’ exists that, like that of Hatten et al., (1988) includes the Yaguajay* and the Jatibonico* belts of this study. Besides, the section exposed in this belt is still largely undivided officially and referred to as the Remedios Group in Pushcharovsky et al. (1988). This name is the extension of a Maastrichtian welldefined unit named Remedios Formation by Bermudez (1950). For this reason, the name Yaguajay* belt will be retained. In central Cuba, the Yaguajay* belt follows the original definition of belts, showing a characteristic sequence of lithologies, dipping 30 –608 south, and bounded to the north and south by major faults, the Yaguajay* and Las Villas* faults, respectively. On air photographs, it forms an easily mappable feature some 80 km (49 mi) long. To the southeast, it terminates at

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FIGURE 62. Stratigraphic section: Yaguajay* belt, Remedios to Sierra de Jatibonico area. the complex convergence of the two bounding faults, whereas to the northwest, it plunges under upper Eocene and later sediments.

Remedios to Sierra de Jatibonico Area The most complete sections are exposed to the northwest near the town of Remedios. The formations established in these sections will be described from oldest to youngest (see Figure 62). Vin ˜ as* Group. —This group includes several similar lithologies that are commonly found together. The essential types are dense, light-gray limestones grading laterally into light-gray pellet limestones and

brown, fine-crystalline dolomites and dolomite breccias. Many of the dolomites appear to be of the high saline type; they are brown, thin bedded, and microcrystalline. The breccias are of a very distinctive type. They are commonly found within sections of the abovementioned dolomites and consist exclusively of the high-saline microcrystalline dolomites in jumbled blocks with suture contacts. They strongly contrast with the numerous heterogeneous carbonate breccias found elsewhere in the section. They have been interpreted as the probable result of anhydrite solution (Littlefield, 1952). The bedding is medium to thick, and the whole sequence is free of terrigenous material.

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In the Vin ˜as River–type section, 10,300 ft (3140 m) have been measured. Its age ranges from the Upper Jurassic through the Cenomanian. This group has been subdivided into the Guani*, Bartolome´*, Puntilla*, and Palenque* formations. Guanı´* Formation. — The Guanı´* Formation consists of 4200 ft (1280 m) of thick-bedded brown, crystalline dolomite, with rare interbeds of limestone and dolomitized limestones. Some dolomite breccias, possibly caused by anhydrite solution, are present. Fossils are absent, but the age, based on the stratigraphic position, is considered Upper Jurassic. The nature of the upper contact with the Bartolome´* Formation is obscured by dolomitization. The upper Guanı´* could be dolomitized lower Bartolome´*. The base has not been observed, but it could be underlain by the Punta Alegre* or the San Adrian Formation. Bartolome´* Formation. — The Bartolome´* Formation consists of 2600 ft (793 m) in the Vin ˜ as River– type section (up to 5000 ft [1525 m] in other areas) of dense, medium- to thick-bedded, hard, light-brown limestone. Some beds are slightly dolomitized, and occasional interbedded dark-brown crystalline dolomites are present. Toward the base, oolitic limestones are present. In the lower part of the formation, the fauna includes Favreina, Dukhania, Valvulinella, and Clypeina, suggesting that the age extends from Upper Jurassic into the Lower Cretaceous. The upper contact with the Puntilla* Formation is conformable. Puntilla* Formation. — The Puntilla* Formation consists of 2200 ft (670 m) in the Camaco River-type section (3400 ft [1037 m] in other sections) of pure light-gray to blue, dense, thick- to medium-bedded miliolid limestones with interbeds of fine- to mediumcrystalline dolomite. At the base of the formation, an 800–1000-ft (245–300-m) dolomite is present. The Puntilla* Formation extends from the Aptian, as indicated by the Orbitolina cf. concava and Orbitolina cf. texana to probably the top of the Cenomanian. The contact with the overlying Camaco* formations is conformable. The Puntilla* Formation is a lateral equivalent of the Palenque* Formation. Palenque* Formation.— The Palenque* Formation (Hatten et al., 1958, described a Palenque Formation that appears to be synonymous with the entire Vin ˜as* Group) consists of 2200 ft (670 m) of massive dolomite breccias with heterogeneous dolomite components up to boulder size in a brown crystalline dolomite matrix. The breccias have interbedded dolomites

and limestones of the Puntilla* type. Anhydrite solution is believed to be the cause of brecciation. This unit is nonfossiliferous, but the age is considered Aptian to Cenomanian based on stratigraphic relationships. The Palenque* is a facies of the Puntilla* Formation and, in places, replaces the upper Puntilla*. It underlies conformably the Camaco* Formation. Hatten et al. (1958) described a Palenque Formation that appears to be synonymous with the entire Vin ˜as* Group. Camaco* Formation. —The Camaco* Formation consists of 2080 ft (635 m) of white to tan, porous algal limestone, thin to thick bedded, and occasionally thinly laminated. Algal remains and miliolids are very abundant. Rudist reefs are common near the base of the formation. In the Camaco River-type section, an 80-ft (25-m) interval of dolomitized limestone sharpstone conglomerate is present 1400 ft (427 m) from the top of the formation and is overlain by the Palone* Formation with apparent but questionable conformity. The Stensio¨ina sp., Cuneolina sp. assemblage indicates a Turonian to Santonian age. It appears to be equivalent to the Purio Formation of Hatten et al. (1958). Palone* Formation. — The Palone* Formation consists of 300 ft (91 m) of cream, organic, medium to fine calcarenite with rare secondary dolomitization. Most of the components are reworked foraminifera and abundant rudist fragments. Based on an Alveolina sp., Siderolites sp., Dicyclina sp., Cuneolina sp., and Coskinolina floridana assemblage, this formation is considered Campanian to early Maastrichtian in age. It is conformably overlain by the Remedios* Formation and is the lateral equivalent of the Mayajigua* Formation. Mayajigua* Formation. —This formation, besides being present in the Yaguajay* belt, is also present in the Cayo Coco–Punta Alegre area of the coastal province, as well as in the Jatibonico* belt. In the Perea-Mayajigua road-type section, it consists of 400 ft (122 m) of thick-bedded heterogeneous sharpstone conglomerate of cream and white, dense limestone and light-brown dolomitic limestone components in a translucent, finely crystalline, white organic limestone matrix. All the components originate from both older and contemporaneous units of the carbonate platform. This conglomerate is very well indurated, hard, and nonporous. The upper part of the formation is less conglomeratic and is made up mostly of medium beds of white, translucent, organic

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limestone similar to the matrix of the conglomerate. In Punta Alegre-1A, it is 640 ft (195 m) thick. Based on a rich Orbitoides sp., Pseudorbitoides sp., Lepidorbitoides sp., and Dicyclina sp. assemblage, the age is considered Maastrichtian. It is the southeastern lateral equivalent of the Palone* Formation and also is interbedded with the Remedios* Formation. It lies unconformably over the Bartolome´*, Florencia*, and Guillermo* formations. It is conformably overlain by the Remedios* Formation and in places unconformably by the lower– middle Eocene. Remedios* Formation. —This formation is best developed to the northwest of the belt and was named by P. Bermudez. It should not be confused with the Remedios Group of Pushcharovsky et al. (1988) that includes all Cretaceous and Jurassic carbonates in the Remedios structurofacies zone. The upper part of Hatten et al. (1958) Remedios Formation is certainly similar to Gulf’s; however, as the descriptions suggest, the lower part might be synonymous to the Mayajigua* and Palone* formations. Lower member. —It consists of 1550 ft (473 m) of brown, finely crystalline dolomite, and limy dolomite with occasional dolomitic limestone beds. The dolomite is massive, but near the top of the member, nearly 300 ft (91 m) of thinly laminated dolomite with laminations exist only a few millimeters apart. Upper member.— It consists of 850 ft (260 m) of dense, white, porcelaneous limestone. In places, the limestone is coarse to fine fragmental, light brown, and occasionally pseudo-oolitic. The beds are 2– 3 ft (60 –90 cm) thick. The thickness of this formation varies considerably, and it appears to lie with apparent conformity, but probable hiatus, under the lower–middle Eocene. The Remedios* Formation is richly fossiliferous and was considered upper Maastrichtian on the basis of a Borelis gunteri, Borelis floridanus, Cosinella sp., Siderolites sp., Rhapydiomina sp., and Gavelinella sp. assemblage. It correlates perfectly with the Cedar Keys of southern Florida. There has been some question as to whether this unit extends into the Paleocene because in Florida, the Cedar Keys is considered to be Paleocene. In view of recent claims of the discovery of Paleocene fossils in the Remedios* Formation, it is pertinent to quote Bro ¨ nnimann (1956, p. 5), who was fully aware of the Paleocene problem. In the writer’s opinion, the Danian is unquestionably a Tertiary stage and forms in the pres-

ent chart part of the Paleocene epoch. . . .Typically Danian faunas with Globigerina daubjergensis Bro ¨ nnimann have not been encountered as yet in Cuba, although such faunas are known from the Gulf Coast. However, assemblages with Globorotalia compressa Plummer, Globigerina pseudobulloides Plummer, and Globorotalia triloculinoides Plummer, and combined with the simultaneous absence of Truncorotalias, are suggestive of Danian or a younger Paleocene stage. Faunas of this composition have been found in Cuba only outside Las Villas province. Therefore, this remains an argument for paleontologists. At any rate, even if the Paleocene is present, it is not well represented. Grande* Formation. —The Grande* Formation consists of 80 ft (25 m) of white and gray, medium to coarse, heterogeneous calcarenite with some pebble conglomerates of white limestone fragments. This unit is very fossiliferous and contains a Tremastegina lopeztrigoi, Discocyclina sp., and Coskinolina sp. assemblage that indicates a lower–middle Eocene age. At this locality, it is conformably overlain by the Sagua* Formation. This unit occurs only at the type locality in the Sagua la Grande River and in the Sierra de Meneses. This name is not to be confused with the Grande Formation as used in Pushcharovsky et al. (1988) to designate limestone and carbonate breccias of Paleocene–Eocene age in the Remedios zone. Sagua* Formation.—This formation is a limestonedolomite conglomerate with angular components up to several feet in size. A fine matrix is very scarce compared to the number of larger blocks. In riverbank outcrops, polished by the stream, it looks like a mosaic of interlocking fragments, with clean suture contacts, smaller ones perfectly filling the space between larger ones. It is extremely hard, with no visible porosity and dogtooth weathering. The fragments consist of all older units of the Yaguajay* and Las Villas* belts. Fragments from the Yaguajay* belt are dominant, 70% or more. In its type locality, it ranges from Albian to lower–middle Eocene, but in the Yaguajay* belt, it is lower–middle Eocene. The lower – middle Eocene part of this formation is also present in the Sagua la Chica* and Las Villas* belts and the coastal province. It will be more fully described under the Sagua la Chica* belt section, below in this chapter, where it has its largest development. It outcrops all along the southern flank of the Yaguajay* belt, where it varies considerably in thickness; it is 80 ft (25 m) thick in the Sagua la Grande area, where it

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overlies the Grande* Formation with apparent conformity, whereas in the Camaco River; it is 690 ft (210 m) thick and rests with strong unconformity over the lower part of the Palone* Formation. In the Yaguajay* belt and coastal province, the Sagua* Formation lies with strong unconformity on older formations and contains a greater amount of components belonging to the older carbonate units. San Martin* Formation. —The San Martin* Formation is well represented in the Yaguajay* belt. In the Sagua la Grande River, 320 ft (97 m) of tan, fine to coarse calcarenites with abundant igneous grains exist, interbedded with pebble conglomerates containing abundant chert fragments and with dull light-gray argillaceous limestones typically shattered in splinters. It will be more fully described under the Las Villas* belt section, below in this chapter. The San Martin* Formation contains a rich foraminiferal fauna. Radiolaria are abundant, and coccolithophoridae and discoasteridae are rock forming. The age is lower –middle Eocene. In this belt, the San Martin* Formation represents the first influx of igneous detritus. This formation underlies conformably the terrigenous clastic Vega* Formation. The San Martin* Formation represents an upward transition from an exclusively carbonate to an exclusively terrigenous detrital regime. Vega* Formation. —The Vega* Formation, which is dominantly an igneous-derived unit, will be described in detail under the Las Villas* belt section. Part of the lower member of this formation, which consists of calcareous shales, igneous-derived sandstones, and occasional sandy limestones, occurs on the Yaguajay* belt. In the Sagua la Grande River where it shows affinities to the San Martin* Formation, the sandstones contain a large percentage of quartz grains. It also occurs in the Sierra de Meneses in a more or less distorted state all along the Las Villas* fault front. Caibarien* Formation. — In the type section, 300 ft (91 m) of Caibarien* Formation have been measured, but as much as 900 ft (275 m) are estimated. It consists of calcarenites and limestone conglomerates, with brown secondary chert, interbedded with chalky and marly limestones. The conglomerates are well and thin bedded, with constituents of nearly uniform size, seldom larger than 5 cm (2 in.). Iron oxide stains are common. In Pushcharovsky et al. (1988), a Caibarien Formation of lower–middle Eocene in the Remedios structurofacies zone described as limestones, marls and carbonate breccias is present; it is not believed to be the same as that of Gulf, although it is probably partly equivalent.

The fauna contains Asterocyclina sp. and Discocyclina sp. and indicates a lower – middle Eocene age. This unit is lithologically related to the San Martin* Formation and is also the lateral equivalent of the Lower Vega* Formation. Drilling.—Two wells were drilled in the Remedios– Sierra de Jatibonico area of the Yaguajay* belt: 1) Atlantic Puntilla-1 to a total depth of 4034 ft (1230 m). It was spudded in the Lower Cretaceous Puntilla* Formation. Orbitolina cf. texana was encountered at 1790 ft (545 m). It probably bottomed in the lower Puntilla* or Bartolome´* Formation. 2) Texaco Mayajigua-1 to a total depth of 10,005 ft (3050 m). It was spudded in the Lower Cretaceous, probably the Puntilla* or Palenque* Formation. At 2580 ft (785 m), the section became dominantly dolomite, possibly the lower Puntilla*, Palenque*, or Bartolome´*. Aptian–Albian was identified at 4850 ft (1480 m), and the section remained in the Lower Cretaceous to total depth. In view of the fact that dips ranged from 30 to 808, the total thickness penetrated was not more than 5740 ft (1750 m).

Sierra de Cubitas Area This area of exposures has the same trend as the Remedios –Sierra de Jatibonico area, but is offset approximately 90 km (56 mi) to the east. It is defined to the south by a line running from Ojo de Agua to Las Mercedes, north of which it terminates. This is the Remedios (2) zone of Pushcharovsky et al. (1988). Gulf did only reconnaissance in this area. The Sierra de Cubitas is a 75-km (46-mi)-long feature prominent in air photographs. It is bound to the south and east by what has been known as the Cubitas fault and disappears to the north and northwest under a Quaternary cover. To the southeast, it terminates against ultrabasics. Generally speaking, the dips are 30– 508 to the south, and the carbonates are cut by several faults parallel to the strike that repeat the section several times across the belt. The section, shown in Figure 63, is reported as follows. Vin ˜ as* Group Undifferentiated. —Formations of the Vin ˜as* Group, with a minimum thickness reported by Hatten et al. (1958) of 1890 ft (575 m), outcrops extensively in the area. This group must include the Palenque Formation, shown as Albian massive limestones by Iturralde-Vinent and de la Torre (1990). Vilato´ Formation.— It consists of an unknown thickness of calcarenites and calcirudites containing

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FIGURE 63. Stratigraphic section: Yaguajay* belt, Sierra de Cubitas area.

abundant rudist (Radiolites) fragments. It is considered of Cenomanian age. Purio Formation. — This name is used to identify an unknown thickness (perhaps in the hundreds of meters) of massive limestones of Turonian to Maastrichtian age. Unnamed Maastrichtian. — This unit is 460 ft (140 m) thick and consists of calcirudites containing the rudist Biradiolites mooretownensis. The following foraminifera have also been reported: Vaughanina cubensis, Vaughanina guatemaltensis, Pseudorbitoides spp., Sulcoperculina globosa, Chubbina cardenasensis,

Sidereolites skoirensis, Sidereolites vanbelleni, and Stomatorbina binkhorsti. Although no name has been given to this unit, it is considered distinctive and separated from the underlying section by Iturralde-Vinent and de la Torre (1990), who consider it the equivalent of the Camajan Formation of Loma Camajan. It is similar and is very probably the equivalent to the Remedios* and Mayajigua* formations. Hatten et al. (1958) reports that the Vin ˜as* Group is overlain by 7000 ft (2135 m) of Remedios Formation, which in this case appears to be synonymous with Vilato´, Purio, and the unnamed Maastrichtian (Remedios* and Mayajigua*) formations.

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FIGURE 64. Eastern Cuba, Yaguajay* belt. This thickness appears excessive, probably because of faulting. The 1988 geologic map (Pushcharovsky et al., 1988) shows that the thickness of the Remedios Group (including the Vin ˜as Group and Hatten’s Remedios Formation) is 2625 ft (800 m). Embarcadero Formation. — Described in Pushcharovsky et al. (1988) as lower–middle Eocene limestone with volcanic fragments and carbonate conglomerates, this description suggests the Sagua* and San Martin* formations. The thickness is given as 165 ft (50 m). In the northern Sierra de Cubitas, Hatten et al. (1958) report an interfingering of the Sagua* with the Jumagua (lower Vega*) Formation. Lesca Formation. —Described in Pushcharovsky et al. (1988) as middle Eocene conglomerates and limestones with chert, this description suggests the Caibarien* Formation. The thickness is given as 330 ft (100 m). Senado Formation.—This unit is described in Pushcharovsky et al. (1988) as olistostromes with blocks of limestone and serpentine, interbedded with sandstones and siltstones of middle Eocene age. As will be seen below, this is unquestionably the upper Vega* (Rosas*) Formation. The thickness is given as 660 ft (200 m).

Northern Oriente: Gibara Area In northern Oriente, only representatives of the carbonate platform and the basic igneous-volcanic provinces are present. The general structural style is a

continuation of that of central Cuba, but is apparently more compressed. The rocks of the carbonate platform form a generally south-dipping, folded and faulted, regional halfdome, bounded on the south by fairly continuous Paleocene –middle Eocene carbonate conglomerates and flysch. These outcrops with the Cubitas Range (in Camaguey) and the Yaguajay* belt (in Las Villas) form the three northwest – southeast-trending and southeast-plunging en echelon carbonate platform antiforms that define most of northern Cuba; these might have been originally separate carbonate banks. Here, the carbonates are present as a group of outcrops covering an area of 22  9 km (13  5.5 mi) west of, and including, the town of Gibara (see Figure 64). This is the easternmost occurrence of carbonate platform sediments in Cuba. Because the dolomitic continental margin carbonate complex is not present, G. Winston (1994, personal communication) considers these carbonates to be unrelated to the FloridaBahamas Platform. He believes them to have been deposited as a separate bank, such as the present-day eastern Bahamas. The limestone massif is surrounded and broken up by several faults. Of interest is that the fault that separates it from the basic igneous-volcanic province dips south and strikes northeast toward the sea, where it terminates offshore on the steep continental slope plunging to 1000 fathoms (1828 m). Although no information about the nature of the contact between

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FIGURE 65. Stratigraphic section: Gibara area, eastern Cuba – northern area.

Cuba and the Bahamas along this part of the Old Bahamas Channel is available (seismic profiles by the University of Texas do not get close enough to shore), it must certainly be a major fault. The section is as follows and shown in Figure 65. Gibara Formation. — The Gibara Formation consists of 2300–2600 ft (700–800 m) of limestones. Some estimates, including that of Pushcharovsky et al. (1988), of up to 20,000 ft (6000 m) exist, with no reference to their source. It would not be surprising if the total thickness of the carbonate platform is on this order

of magnitude, but it is doubtful that such a thickness is exposed in this area. The lower part of the formation consists of brownish white, compact, medium-bedded, crystalline limestones with intercalations of yellowish white, sometimes laminated, hard, microcrystalline limestones. It is separated by a slight angular discordance from an upper part, consisting of massive, crystalline, medium- to coarse-grained, yellowish gray limestones with abundant rudist remains. The uppermost part of the formation contains yellowish white, dense, microcrystalline, pelagic limestones.

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Beds of dolomite and dolomitic limestones are present; the most persistent has been named the Jobal Formation. The description suggests that one is dealing with at least two and possibly three units. The fauna of the lower part of the formation is characterized by Coskinolinoides cf. texanus, Dictyoconus cf. walnutensis, Orbitolina sp., Nommoloculina helmi, Milliolina sp., Planomalina buxtorfi, and Ticinella sp., indicating an Aptian–Albian age. The upper part contains Globotruncana arca, Globotruncana contusa, Globotruncana caliciformis, Globotruncana conica, Globotruncana fornicata, Globotruncana lapparenti bulloides, Globotruncana linneana, Globotruncana stuarti, Hedbergella sp., radiolaria, and rudistids. This latter assemblage is definitely Upper Cretaceous, possibly Turonian–Maastrichtian, and, except for the rudistids that are probably detritus, indicates pelagic depositional conditions similar to those of the Casablanca Group in the Cayo Coco – Punta Alegre and northwestern Cubitas of central Cuba; pelagic faunas are typically absent in the carbonate platform sediments. The mention of strong folding, observed in the upper part of the Gibara Formation, also suggests the thin-bedded marly limestones characteristic of the upper Casablanca Group. The lower part of the Gibara Formation is similar and correlative with the Puntillas* Formation of the Vin ˜as* Group. The upper part definitely suggests the Casablanca Group. El Jobal Formation.— El Jobal Formation consists of 230–330 ft (70–100 m) of gray to dark-brownish or pinkish gray, sugary, medium- to coarse-crystalline dolomites and dolomitic limestones. It is believed to be a facies of the upper part of the Gibara Formation. The dolomites are barren of fossils, but a limestone interbed has been found to contain Milliolina sp., Sulcoperculina sp., Vaughanina cubensis minor, Orbitoides murchissoni, Orbitoides tissoti, Pseudorbitoides sp., Sulcorbitoides sp., and rudist fragments, indicating an upper Campanian–lower Maastrichtian age. This unit is similar and equivalent to the Palone* Formation and is also equivalent to the Mayajigua* Formation. Embarcadero (Embarcadero Oriental) Formation. — This name has been used to designate the Sagua*-like conglomerate that outcrops in the Sierra de Cubitas in central Cuba. In Pushcharovsky et al., 1988, it is named Embarcadero Oriental. The formation consists of 150–1000 ft (50–300 m) of limestone and dolomite conglomeratic breccia made up of 95% of detritus, of which 90% consist of the various limestone types found in the older carbon-

ate platform, 6–8% of dolomites, and 2–4% of chert. The percentage of igneous components from the basic igneous-volcanics is very small. This conglomerate is identical with the Sagua* Formation of central Cuba, which ranges from the Aptian– Albian to the lower–middle Eocene, where it becomes geographically very extensive. No indigenous fauna has been found, and its age is based on components and because it underlies the upper Paleocene–middle Eocene Vigia Formation. The Vigia Formation correlates with the San Martin* and Vega* formations of central Cuba; therefore, whether the Sagua* or Embarcadero are Paleocene or lower–middle Eocene, they are coeval and reflect the same process. Vigia (Vigia Oriental) Formation.—The Vigia (Vigia Oriental) Formation (in Pushcharovsky et al., 1988, it is named Vigia Oriental) consists of up to 2300 ft (700 m) of mostly igneous-derived clastics, detrital limestones, and tuffs as follows: 1) The lower part of the formation consists of an interbedding of green to grayish green serpentine, limestone, and volcanic-derived graywacke sandstones and mudstones. They are well bedded, and their grain size varies from coarse to fine and sometimes contain large foraminifera. 2) The upper part consists of thin and well-bedded white to grayish white, calcareous, commonly silicified tuffs, and radiolaria-bearing marls, with bentonite. Rhyodacites and greenish gray, dense rhyodacitic tuffs are also present. The rhyodacites are white to grayish white and porphyritic, with phenocrysts of biotite, quartz, amphibole, and plagioclase up to 2 mm (0.08 in.) in diameter. The tuffs are commonly silicified or zeolitized. A rich, foraminiferal fauna contains Globorotalia (Acarinina) acarinata, Globorotalia (Acarinina) densa, Globorotalia (Acarinina) mckannai, Globorotalia (Acarinina) pentacamerata, Globorotalia (Acarinina) rugosoaculeata, Globorotalia (Acarinina) spinuloflata, Globorotalia (Acarinina) triplex, Amphistegina lopeztrigoi, Anomalina grosserugosa, Asterocyclina sp., Clavulina parisiensis, Cribohantkenina bermudezi, Dictyoconus americanus, Dictyoconus cookei, Discocyclina crassa, Discocyclina flintensis, Discocyclina pustulosa, Discocyclina vermunti, Ellipsoglandulina velascoensis, Ellipsonodosaria annulifera, Globigerina pseudoeocenica, Globigerinoides higginsi, etc. The age is considered upper Paleocene–middle Eocene. The Vigia Formation overlies unconformably the Embarcadero and the Gibara formations. It is equivalent to the Miranda and Castillo de los Indios formations of southeastern Oriente. The lower part of

102 / Pardo

FIGURE 66. Central Cuba, coastal areas.

this formation represents a flysch deposited in deep waters similar to, and coeval with, the Manacas Formation (Pica Pica Member) of western Cuba and the Vega* Formation of central Cuba. However, the upper part is of volcanic origin and of a volcanism synchronous to, and even postdating, the major thrusting episode of the orogeny.

Yaguajay* Belt Discussion This section exposes a minimum of ±8400 ft (±2550 m) of Tithonian and Lower Cretaceous massive, bank-type carbonates. Dolomite breccias are occasionally common, and evaporites are absent. The Upper Cretaceous (and possible Paleocene) is characterized by ±5600 ft (±1700 m) of occasionally richly fossiliferous limestones and occasional dolomites. It includes the regionally persistent, Campanian to lower Maastrichtian carbonate conglomerate of the Mayajigua* Formation, which is mainly derived from reef material. Finally, during the lower–middle Eocene, ±2200 ft (±700 m) were deposited, which are characterized by the coarse-grained Sagua* conglomerate followed by the San Martin* and younger detrital limestones and clastics where igneous fragments, derived from the orogenic front to the south, make their first appearance. The entire section was deposited

under shallow water, and although the evaporites are absent, it shows great affinity to the Bahamas section. The above thickness figures give a constant average rate of sedimentation (uncorrected for compaction) of 167 ft/Ma (51 m/Ma) from the middle Kimmeridgian through the middle Eocene or 114 Ma. However, the Upper Jurassic alone could show a higher rate of sedimentation depending on the age of the observed base of the Guani* Formation, which is unfossiliferous.

Coastal Region This region runs along the north coast. It is present north of a line as follows: It runs north of the Bahia de Cardenas, through Jumagua, Sagua la Grande, the confluence of the Camajuani and Sagua la Chica rivers, north of Remedios, along the north flank of the Sierra de Bamburanao, south of Yaguayay, Chambas, Moron, Loma Cunagua, Bolivia, along the north flank of the Sierra de Cubitas, La Gabriela, and goes to sea north of Nuevitas (see Figure 66). The original name, by Pardo (1953), was the Coastal Belt and was defined as the entire coastal area including the cays, with little or no pre–upper Eocene

Pre – Upper Eocene Stratigraphy / 103

outcrops, and where the sparse drilling (Gulf Blanquizal III-1, Shell Cayo Coco-2, Shell Punta Alegre-1A, Shell Punta Alegre-2) indicated a carbonate platform section with less structural complications than in the Yaguajay* belt, farther to the south. This was a departure from either the Pardo (1953, 1954) or HattenMeyerhoff (Hatten et al., 1958) definition of belts (units). In 1956b, Truitt restricted the coastal belt to a lithologic-type section as encountered in the well Shell Cayo Coco-2 (the stratigraphic definition of belt). The same area was named the Cayo Coco tectounit by Hatten et al. (1958) and the Cayo Coco belt by Pardo (1975). However, this restricted definition was difficult to extend outside the Cayo Coco–Punta Alegre area because of the lack of information, and Hatten et al. (1958) included in it the area north of the Sierra de Cubitas, although there was no information on the Lower Cretaceous–Upper Jurassic facies. Further drilling of the Kewanee Collazo-1 and Shell Manuy-1 wells and the scarce information available on the deep wells drilled by ICRM suggest facies changes within the coastal province and a much greater structural complexity, impossible to resolve with the information at hand. For this reason, it is suggested that the coastal areas of Las Villas and Camaguey, extending from Gulf Blanquizal III-1 to the town of Nuevitas, north of the Yaguajay* belt of carbonate platform outcrops, be named the coastal region, outside the belt (unit) classification scheme. For description purposes, this region will be subdivided into areas: the Cayo Coco–Punta Alegre (east) and the Blanquizal (west). In addition, a short description of the well Gulf-Chevron Cay Sal-1 as well as a discussion of the south Bahamas Platform will be provided under the Bahamas area.

Cayo Coco–Punta Alegre Area The section shown in Figure 67 is a composite section based on the Shell wells Cayo Coco-2, Punta Alegre-1A, and Punta Alegre-2. The sequence from older to younger is as follows: Cunagua Salt. — It is believed to be at the base of the section, although this unit has never been penetrated in this area in a normal stratigraphic position. Punta Alegre* Formation. — Although this unit has not been drilled in a normal position in this area, it is believed to be transitional between the evaporites and the Cayo Coco Formation. The breccia must be in part tectonic, but in part due to solution of the anhydrite. The abundance of components derived from a silicoclastic section suggests some relationship with the San Adrian and the San Cayetano Formations.

Cayo Coco* Formation.—In the Shell Cayo Coco-2 type section, it extends from 3998 ft (1218 m) to total depth at 10,563 ft (3220 m) for a total thickness, corrected for dip, of 5684 ft (1733 m). The dips average 308. 3998 – 7150 ft (1218 –2180 m). The upper 2728 ft (832 m) consists of massive to thick-bedded, brown to light-brown, micro- to medium-crystalline dolomites and minor dolomitized oolitic zones. Anhydrite occurs in minor amounts commonly as vug fillings. Many zones of healed, brecciated dolomite are present; Shell geologists called it the ‘‘upper (breccia) dolomite group.’’ Some clayshale laminae exist. 7144–10,563 ft (2178–3220 m). The lower 2956 ft (901 m) of the section consists of dolomites, calcarenites, and micritic limestones interbedded with characteristic, sometime massive, white to brown, micro- to fine-crystalline anhydrites. The dolomites are brown in color, micro- to coarse crystalline, with traces of anhydrite. The limestones are light brownish gray and contain microfossils, and the calcarenites are coarse grained and oolitic. A continuous limestone interval exists from 8982 to 9245 ft (2739 to 2819 m). G. Winston (1984, personal communication) considers the top of this lower section at 7144 ft (2178 m) correlative with the top lower Comanchean (middle Aptian), Punta Gorda Formation in Florida (COSUNA, 1988). Within the brown dolomites of this lower section are several zones of good intergranular to vugular porosity (up to 15%) from 8112 to 8350 and 8765 to 9000 ft (2473 to 2546 and 2672 to 2744 m). Tests indicated zones of reservoir-quality permeability. G. Winston (1984, personal communication) considers these two intervals of brown dolomite to be a section, repeated by a thrust fault at 8349 ft (2545 m), that correlates with the lower Able Member and upper Twelve Mile Member of the Lehigh Acres Formation of south Florida. However, either this lithology is younger in Florida, or unknown structural complications exist in Shell Cayo Coco-2. G. Winston (1984, personal communication) considers the Lehigh Acres Formation lower Comanchean (middle Aptian; Childs et al., 1988), whereas Upper Jurassic fossils have been identified at 9005 ft (2745 m) in Shell Cayo Coco-2. Asphalt stains are common throughout the entire section. Coskinolinoides cf. C. texanus, considered an Aptian– Albian index (lower Fredericksburg) in the Gulf Coast,

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FIGURE 67. Stratigraphic section: coastal province, Cayo Coco – Punta Alegre area.

was found at 6667 ft (2032 m). Saccocoma sp., Cuneolina sp., and Favreina joukowskyi, considered Upper Jurassic indicators in Cuba, were found at 9005 ft (2745 m). Based on scant but reliable paleontological evidence and its position underlying the Aptian (possibly extending into the Neocomian) Guillermo* Formation, the Cayo Coco* is therefore considered to range from the Upper Jurassic into the Aptian. The lower contact has never been drilled. The Cayo Coco* Formation is probably underlain by the Punta Alegre* or San Adrian formations. However, the possibility exists that the lower part of the Cayo Coco*

Formation is synonymous with the upper part of the Punta Alegre* Formation. The upper contact with the Guillermo* Formation is obscured by dolomitization but is believed to be transitional. The Cayo Coco* Formation is time equivalent to the lower and middle part of the Vin ˜ as* Group and represents a similar carbonate bank-evaporitic facies. It is very similar to the Guani*, Bartolome´*, and Palenque* formations of the Yaguajay* belt, the main difference being the presence of anhydrites in the Cayo Coco* Formation. As already mentioned, the absence of anhydrite in the Vin ˜ as* Group

Pre – Upper Eocene Stratigraphy / 105

is believed by some workers to be due in large part to a later solution as indicated by the frequent intraformational dolomite breccias. Except for Hatten, Meyerhoff, and associated authors, the name Cayo Coco* Formation has been used fairly loosely in the literature, scout reports, and other sources of information. The Cayo Coco* Formation was also penetrated in Kewanee Collazo-1 from 8395 ft (2559 m) to total depth at 13,030 ft (3973 m). The interval from 8395 to 12,250 ft (2559 to 3735 m) or 3796 ft (1157 m) of thickness (after correction for an average 108 dip) suggests the upper dolomite section in Shell Cayo Coco-2. Below 12,250 ft (3735 m), 447 ft (136 m) of section (after correction for an average 558 dip) suggests the lower anhydrite-dolomite section in Shell Cayo Coco-2. Favreina joukowskyi was found at 12,730 ft (3881 m). Casablanca Group. — Giedt and Schooler (1959) described an assemblage of lithologies from the coastal plain south of Guaney Beach, Camaguey, northwest of the Sierra de Cubitas. It consists of light-gray to yellowish gray, thin- to medium-bedded, fine-grained limestones, with shaley intervals between the limestone beds. The limestone is slightly chalky and contains an abundant microfauna and poorly preserved ammonites. These lithologies are similar to a section from 950 to 4000 ft (290 to 1220 m) in Shell Cayo Coco-2, where Pardo (1954) named three units, which, in ascending order, are the Guillermo*, Romano*, and Contrabando* formations. In this study, the Casablanca Formation has been elevated to group status, and it includes the three above-named formations. The thickness in Shell Cayo Coco-2 might be exaggerated in view of reported high dips. Guillermo* Formation. — It consists of massivebedded, pelagic foraminiferal white limestone and appears to be unconformably overlain by the Romano* Formation. It contains abundant Nannoconus spp., Favusella washitensis, and Colomiella spp. Based on the fauna, it is considered Aptian to lower Albian and possibly extending into the Neocomian. It is, in part, the deep-water equivalent of the upper Cayo Coco* Formation. In Shell Cayo Coco-2, the type section, it is found between 3500 and 4000 ft (1067 and 1220 m). The Guillermo* Formation has been found in Shell Punta Alegre-2 between 3970 and 4220 ft (1210 and 1287 m) and Shell Manuy-1 between 985 and 1213 ft (300 and 369 m). It is unconformably overlain by the upper Maastrichtian Remedios* Formation. It is absent, possibly faulted out in Shell Punta Alegre-1A, and has not been specifically recognized in Kewanee Collazo-1.

Romano* Formation. — It consists of an interbedding of argillaceous limestones, marls, and some shales. It is comformably overlain by the Contrabando* Formation. Based on abundant planktonic foraminifera with Globigerina cretacea sl., Guembelina sp., and Nannoconus spp., it is considered of Albian age. The influx of argillaceous material in this deep-water environment is a definite departure from the previously predominant pure carbonate environment. Its type locality is the 2380 –3500-ft (726 – 1067-m) interval in Shell Cayo Coco-2. It is also present in Shell Punta Alegre-1A from 1225 to 1520 ft (373 to 463 m). It is missing through unconformity in Shell Punta Alegre-2 and is not present in Shell Manuy-1. It has not been specifically recognized in Kewanee Collazo-1, but it could be present because the interval 8060 – 8395 ft (2457 – 2559 m) has been reported as limestone-chert-shale of Albian – Cenomanian – Turonian age; this could be an interval of tectonically disturbed Casablanca Group. Contrabando* Formation. — It consists of chalky limestone and marl, sometimes dolomitic, containing characteristic nodular black chert stringers. It contains abundant pelagic foraminifera, among them G. cretacea sl., Guembelina sp., and Rotalipora appenninica. It is considered Cenomanian –Turonian age and might extend into the Coniacian. As will be seen later, this unit is lithologically and paleontologically very similar to the Calabazar* Formation of the Las Villas* belt. It is unconformably overlain by the Mayajigua* Formation. The type locality is the 950–2380-ft (290– 726-m) interval in Shell Cayo Coco-2, where the upper part is truncated by the younger Tertiary unconformity. It is present in Shell Punta Alegre-1A from 920 to 1225 ft (280 to 373 m). It is probably present in Kewanee Collazo-1 (see Romano* Formation description above). It is absent in Shell Manuy-1. The Casablanca Group, with its definite openmarine, deep-water, pelagic environment, has been considered, in the past, as one of the characteristics of the Cayo Coco belt (unit). Mayajigua* Formation. —This formation is well represented in the Cayo Coco–Punta Alegre area. It is present in Shell Punta Alegre-1A from 280 to 920 ft (85 to 280 m) and Kewanee Collazo-1 from 7347 to 8065 ft (2240 to 2459 m). It has not been specifically identified in Shell Manuy-1, but based on sample descriptions and the presence of a rich Maastrichtian orbitoid fauna, it is believed to be present under the Cayo Coco* Formation after crossing a major fault at

106 / Pardo

±8000 ft (±2400 m). In Shell Cayo Coco-2, it is missing because of the Tertiary unconformity. Jaula* Formation. — It consists of calcarenite of lower – middle Eocene age. It is present in Kewanee Collazo-1 from 6550 to 7347 ft (1997 to 2240 m), where it overlies the Mayajigua* Formation. It is the correlative of the Sagua* Formation. In Pushcharovsky et al. (1988), the Guaney Formation is overlain by middle Eocene limestone with breccias called the Venero Formation. It is a possible synonym of the Jaula* Formation and even the Turiguano* Formation. Turiguano* Formation. — The type locality of this formation is a small outcrop north of the Isla de Turiguano diapir. It consists of white calcarenite with abundant dolomitization and a few dolomite intervals of lower–middle Eocene age. In Kewanee Collazo-1, it is present from 4325 to 6550 ft (1319 to 1997 m), where it overlies the Jaula* Formation. With correction for an average 208(?) dip, this represents a thickness of 2091 ft (637 m). It is present in Shell Punta Alegre-2 from 3548 to 3970 ft (1082 to 1210 m), where it overlies the Guillermo* Formation with possible unconformity. It is the equivalent to the Caibarien* Formation of the Yaguajay* belt. It is unconformably overlain by various upper Eocene or younger units; however, in the Kewanee Collazo-1 and the Shell Punta Alegre wells, it is overlain by the lower Oligocene Chambas* Formation. Drilling. — In addition to Shell Cayo Coco-2 and Kewanee Collazo-1, several deep wells have been drilled in this area. Sparse information is available on them from the 1985 Cuban geologic map (Cuba, 1985a, b) and Petroconsultants (1989, personal communication) and no dips or lithologic details are given. This makes precise assignment of formational unit and correlation with the other wells in the area very difficult if not impossible. For instance, it is impossible to determine whether the Casablanca Group is present in the ICRM wells, although the equivalent time interval from Aptian to Turonian is shown in several of them. The wells are Shell Manuy-1, and ICRM Cayo Fragoso-1, ICRM Cayo Frances-5, ICRM Cayo Lucas-1, ICRM Cayo Romano-1, and ICRM Moron Norte-1. 1) Shell Manuy-1. Neogene carbonates to ±655 ft (±200 m), Campanian–Maastrichtian limestones to ±1015 ft (±310 m), Aptian–Albian limestones to ±1575 ft (±480 m), Upper Jurassic – Neocomian dolomites (possible Cayo Coco* Formation) to ±7215 ft (±2200 m), Paleocene detrital carbonates to ±7545 ft (±2300 m), and Campanian – Maastrichtian limestones to total depth at 8895 ft

2)

3)

4)

5)

(2712 m). However, reliable reports indicate that the well was cut by several thrust faults; at ±1600, ±6000, and ±8000 ft (±480, ±1800, and ±2400 m), repeating the Casablanca Group and some younger units several times. ICRM Cayo Fragoso-1. Oligocene and younger carbonates to ±2330 ft (±710 m), lower – middle Eocene detrital carbonates to ±2820 ft (±860 m), Coniacian–Maastrichtian limestones and dolomites to ±6079 ft (±1850 m), Albian–Turonian limestones and dolomites to ±11,250 ft (±3430 m), and dolomites and anhydrite of Upper Jurassic and Neocomian age (possibly Cayo Coco* Formation) to total at 16,450 ft (5014 m). ICRM Cayo Frances-5. Neogene and Oligocene limestones drilled from the surface to ±2230 ft (±680 m), middle – upper Eocene limestones to ±2755 ft (±840 m), Albian – Maastrichtian limestones to ±8005 ft (±2,440 m), Neocomian dolomite (no anhydrite) to ±11,415 ft (±3480 m), and Aptian–Turonian limestones and dolomites to total depth at 14,881 ft (4537 m). Petroconsultants reports that the well penetrated Lower Cretaceous limestones and anhydrites at 11,513 ft (3510 m). This could be interpreted as the well having drilled through ±3600 ft (±1070 m) of upper Cayo Coco* Formation before crossing a thrust at 11,513 ft (3510 m). ICRM Cayo Romano-1. This well has the most conflicting information. The 1985 geologic map (Cuba, 1985a, b) shows middle Eocene and younger Tertiary to ±680 ft (±280 m), Campanian – Maastrichtian limestones to ±1445 ft (±440 m), Cenomanian – Senonian dolomite to ±7350 ft (±2240 m), and Aptian – Turonian limestones to total depth at 13,317 ft (4060 m). However, a 1989 Petroconsultants report (personal communication) shows Tertiary to 275 ft (84 m), Maastrichtian to 623 ft (190 m), Cenomanian – Turonian to 1591 ft (485 m) Albian to 4838 ft (1475 m), Neocomian–Aptian to 7915 ft (2413 m), Tithonian to 8397 ft (2560 m), Upper Cretaceous limestones to 11,808 ft (3600 m), Lower Cretaceous dolomite to 12,792 ft (3900 m), and Neocomian dolomite to total depth. In view that the presence of a thick dolomite section in the Upper Cretaceous in this area is rather unusual, the author is inclined to think that the geologic map is in error, and that the well did cross a major thrust fault at 8397 ft (2560 m). ICRM Moron Norte-1. Upper Eocene and younger terrigenous clastics penetrated from the surface

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FIGURE 68. Stratigraphic section: coastal province, Blanquizal area. to ±6165 ft (±1880 m), Cretaceous volcanics to ±9185 ft (±2800 m), Paleocene coarse terrigenous clastics to ±9480 ft (±2890 m), Neocomian dolomite suggesting the Bartolome´* (or Cayo Coco*) Formation to total depth at 16,407 ft (5002 m). The well must have crossed the Domingo thrust at ±9185 ft (±2800 m).

Blanquizal Area Gulf’s Blanquizal III-1 is representative of this area that is characterized by a lack of anhydrite and continuous shallow-water conditions through the Cretaceous. The section shows great affinity to that of the Yaguajay* belt, and this well could have penetrated the offshore extension of this belt (see Figure 68). 0 – 196 ft (0 – 60 m). Gu ¨ ines Formation consisting of light tan reefoidal porous, locally dolomi-

tized limestones, marls, and calcarenites of Miocene age. 196 – 1775 ft (60 –875 m). Upper Cretaceous tan, cream, and gray fine-crystalline limestones with rare dolomites. It is typical of the Remedios* and possibly Palone* formations. 1775 – 2872 ft (541 – 875 m). Upper Cretaceous consisting of dolomitized, richly fossiliferous miliolid limestones, with rudist fragments typical of the Camaco* Formation. A 3-ft (1-m) shaley bed containing rock-forming Pithonella spp. as well as Globigerina cretacea sl. and Guembelina sp. of early Upper Cretaceous age was encountered at 2180 ft (665 m). This was the only evidence of open-water pelagic conditions. 2872 – 5330 ft (875 –1625 m). Lower Cretaceous tan and brown finely crystalline dolomites and dolomite breccias and cream, brown, and tan

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limestones, commonly with miliolids, of the Puntilla* and equivalent Palenque* formations. Littlefield (1959) interpreted the fine-crystalline dolomites as primary. Circulation was lost at 4208 ft (1283 m), indicating the cavernous (boulder) zone. The Aptian – Albian Orbitolina cf. texana is present at 4745 ft (1447 m). The top of the Lower Cretaceous has been a matter of discussion; it is certainly below 2180 ft (665 m), but correlation with Cay Sal-1 could place it as high as 2250 ft (686 m). It should be noted that long stretches of dolomite section are completely devoid of identifiable fossils, and many of the limestones contain only nondiagnostic, facies-dependent faunas. 5330 to total depth at 11,218 ft (1625 to total depth at 3419 m). It consists dominantly of tan, gray, and brown very fine to microcrystalline dolomite of the Lower Cretaceous Bartolome´* Formation. Two intervals of cream, tan, brown, and white fine- to coarse-grained, commonly miliolidrich limestones at 7033–7180 ft (2144–2189 m) and 9875–10,113 ft (3011–3083 m), respectively. Littlefield (1952) interpreted the well as having crossed a major thrust fault at 7650 ft (2332 m), repeating ±3000 ft (±900 m) of section, although this has never been definitely confirmed. G. Winston (1986, personal communication) makes the following correlations with Florida, but considers them ‘‘iffy:’’ Rattlesnake Hammock, 4650 ft (1418 m); Sunniland, 4740 ft (1445 m); West Felda, 6520 ft (1988 m); Pumpkin Bay, 6550 ft (1997 m); Bone Island, 7980 ft (2433 m); and Wood River, 10,350 ft (3155 m). No indication of anhydrite exists, although common dolomite breccias are present, which Littlefield (1952) believed were caused by anhydrite solution. G. Winston’s correlations suggest that the well penetrated the Jurassic at 10,350 ft (3155 m). Gulf’s opinion at the time was that the well’s total depth was still in the Lower Cretaceous. Another well, ICRM Cayo Lucas-1, might also have been drilled in this area, but published information does not permit a positive determination; no evaporites were mentioned. ICRM Cayo Lucas-1. —Upper Eocene and younger limestones drilled from the surface to ±920 ft (±280 m), Campanian – Maastrichtian limestones to ±2100 ft (±640 m), Cenomanian – Santonian limestones to ±2950 ft (±900 m), Aptian – Turonian limestones to ±8460 ft (±2580 m), Neocomian dolomite (possibly Bartolome´* or upper Cayo Coco*) to total depth at 10,152 ft (3095 m).

Florida-Bahamas Area Many wells have been drilled in southwest Florida, and five wells have been drilled in the Bahamas: Superior Andros-1, Chevron Great Isaac-1, Gulf-Mobil Long Island-1, Tenneco Doobloon Saxon-1, and GulfChevron Cay Sal-1. Only the last two have a direct bearing on Cuba’s coastal province. Winston (1991) is a good source of general information on the Bahamas and Florida stratigraphy. 1) Tenneco Doubloon Saxon-1. This well was drilled in the southern Bahamas, 43 km (26 mi) northeast from Cayo Coco-2 and, according to Petroconsultants (1988, personal communication), was in the dolomites and anhydrites of the Cayo Coco* Formation at a total depth of 21,740 ft (6628 m). Oil shows were reported. Unfortunately, no other details are available. 2) Gulf-Chevron Cay Sal-1. This well was jointly drilled 82 km (50 mi) north-northeast of Gulf Blanquizal III-1 by Standard of California and Gulf Oil to a total depth of 18,906 ft (5764 m). According to G. Winston (1991, personal communication), the section is as follows (see Figure 69): 0– 1400 ft (0 – 427 m). Post-Eocene white micritic limestones and white euhedral microcrystalline dolomites. 1400 – 3620 ft (427 – 1104 m). Eocene tan, cream, and white micritic limestones with skeletal remains and orange-brown euhedral fine to microcrystalline dolomite. 3620–4680 ft (1104–1427 m). Paleocene limestone, dolomite bank facies, and dolomite reef facies. The limestone is nonporous, white lithographic, and chalky. The bank facies dolomite is nonporous, cryptocrystalline, light gray, and tan. Numerous beds of porous euhedral fine-crystalline dolomite are interbedded with the above. The reef facies is medium- to coarse-crystalline, euhedral, and porous dolomite. 4680 to ±7300 ft (1427 to ±2226 m). The Upper Cretaceous consists of 1460 ft (445 m) of massive tan, cream, light- to dark-gray, fine- to microcrystalline dolomite. It overlies 470 ft (143 m) of white chalky limestone with dolomite inclusions. The base is made of 690 ft (210 m) of tan and brown, euhedral fine- to medium-, and occasionally, coarsecrystalline dolomite. The coarse dolomite appears to have a reef origin. The dolomite is very porous, and large cavities (caverns at the base of the interval) exist. The exact boundaries are questionable.

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FIGURE 69. Stratigraphic section: Bahamas Gulf-Chevron Cay Sal-1. Lithology and correlations courtesy of G. Winston.

±7300– 10,310 ft (±2226– 3143 m). Much of the Albian and the upper part of the Aptian to the top of the Lake Trafford Formation consist of the lower part of the Rattlesnake Hammock Formation overlain by 2540 ft (774 m) of cream to tan, cryptocrystalline to anhedral dolomite called the Cay Sal dolomite. The lower 480 ft (146 m) of section consists of an interbedding of tan, brown, and cryptocrystalline to euhedral dolomite, cream to tan micritic limestones, and a minor amount of anhydrite. 10,310 –10,460 ft (3143 –3189 m). It consists of tan micritic limestone and tan, euhedral, and microcrystalline dolomite of the Lake Trafford Forma-

tion. Anhydrite is present. This interval represents the beginning of continuous evaporitic conditions in Cay Sal. 10,460–10,620 ft (3189–3238 m). It consists of tan, micritic limestone with rare tan, microcrystalline dolomite and anhydrite of the Sunniland Formation. 10,620–11,500 ft (3238–3506 m). This is the first interval consisting dominantly of anhydrite. The subordinate carbonates are dominantly tan and brown micritic limestones with occasional skeletal remains. Minor microcrystalline tan and brown dolomite also exists. It is considered equivalent to the Punta Gorda Formation.

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FIGURE 70. Stratigraphic sections: coastal province, Gulf Blanquizal III-1 to ICRM Cayo Romano-1. 11,500–13,850 ft (3506–4223 m). This interval consists of dominantly cream, brown, and tan, micritic limestones interbedded with subordinate amounts of brown and tan, medium- to microcrystalline dolomites and subordinate anhydrite of the Able, Twelve Mile, West Felda(?), and Pumpkin Bay formations. 13,850–16,200 ft (4223–4938 m). This interval consists of 35% of anhydrite with tan to brown, micritic to lithographic limestone as the dominant carbonate. The dolomite is tan to brown, very fine to fine crystalline. It represents the Bone Island Formation. G. Winston considers it to represent the lower part of the Coahuilan and the upper part of the Jurassic. The COSUNA Charts (Childs et al., 1988) consider it of Berriasian to Hauterivian (Durangoan) age. 16,200 to total depth at 18,906 ft (4938 to total depth at 5764 m). It consists of anhydrite interbedded with tan to brown cryptocrystalline dolomite with occasional remains of oolites. Some subordinate brown to tan micritic limestones exist. A few thin salt beds are present near the bottom of

the section, which caused considerable drilling difficulties. Winston considers this interval to be the Wood River Formation of Jurassic age. The COSUNA Charts (Childs et al., 1988) consider it of Tithonian (Lacastian) age. At the time of the drilling, Gulf’s geologist on the well, R. A. Worrell, also considered the well to have bottomed in the Jurassic.

Jurassic–Cretaceous Carbonate Platform Discussion The carbonate platform southern boundary is well defined by the Yaguajay* belt. This province can be divided into two areas on the basis of the distribution of facies; however, this facies distribution is not necessarily related to identifiable structural features. Because of the lack of information, it is difficult to draw a boundary between the areas. Figure 70, based on the ICRM wells, Gulf Blanquizal III-1, and Shell Cayo Coco-2 (shown in Cuba, 1985a, b), shows a spectacular increase in the thickness of the interval between the top of the Neocomian

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and the top of the Cretaceous in the 85 km (52 mi) between Shell Cayo Coco-2 and ICRM Cayo Fragoso-1, from ±3410 to ±8365 ft (±1040 to ±2550 m). In Gulf Blanquizal III-1, this interval is at least 5134 ft (1565 m) thick. In the Yaguajay* belt, this same interval is 10,780 ft (3290 m). In addition, this interval is shown containing dolomites in ICRM Cayo Fragoso-1. Dolomites are present in this interval in Gulf Blanquizal III-1 and the Yaguajay* belt, whereas dolomites are absent in the Cayo Coco – Punta Alegre area. In GulfChevron Cay Sal-1, the Upper Cretaceous consists of 3100 ft (945 m) of dominantly dolomites. This indicates that the basic difference between the Cayo Coco– Punta Alegre area and the Yaguajay* belt–Blanquizal area is that in the former, the carbonate platform conditions were replaced by pelagic, deeper water conditions from the lower Aptian to the Maastrichtian, whereas in the latter, they persisted at least until the end of the Cretaceous or Paleocene. This change occurred along a line running approximately from Cayo Frances through Chambas, Moron, Bolivia, and along the northern border of the Sierra de Cubitas, suggesting the presence of a deep-water tongue, possibly an ancestral Old Bahamas Channel, along the north coast of Cuba. The presence of Cenomanian, open-water Oligostegina limestone in Gulf Blanquizal III1 at 2180 ft (665 m) indicates the proximity to such a feature. However, note that in the well ICRM Cayo Romano-1, 3411 ft (1040 m) of Upper Cretaceous limestones were reported under the fault in the Tithonian at 8397 ft (2560 m) compared to the 1315 ft (401 m) in the upthrown block. It is not known whether this difference in thickness is caused by an incomplete section in the upthrown block, steep dips in the downthrown block, or the superposition of two different facies. Anhydrite beds occur, or have been reported, in the Cayo Coco* Formation only in ICRM Cayo Fragoso-1, Shell Cayo Coco-2, and in the lowermost part of the section penetrated by Kewanee Collazo-1. No anhydrite is present, or has been reported, in the Lower Cretaceous or Upper Jurassic of the Yaguajay* belt (Remedios – Sierra de Jatibonico and Cubitas areas), Gulf Blanquizal III-1, Shell Manuy-1, and the ICRM’s wells Cayo Frances-5, Cayo Lucas-1, Cayo Romano-1, and EPEP Moron Norte-1, although collapse breccias in high-saline dolomites are common in the Yaguajay* belt and Gulf Blanquizal III-1. In view of the fact that no dip information for the ICRM wells exists and that Shell Manuy-1 is apparently very disturbed structurally, it is impossible to say whether the above wells might not have drilled through the upper ±3000 ft (±900 m) of the Cayo Coco* Forma-

tion, where no anhydrites are found. The well GulfChevron Cay Sal-1 shows 3010 ft (918 m) of Lower Cretaceous dolomites overlying 8596 ft (2621 m) of interbedded dolomites and anhydrites. This section certainly suggests the Cayo Coco* Formation. However, in this well, the Upper Cretaceous consists of 2620 ft (799 m) of dominantly dolomites with some interbedded limestones with no indication of Casablanca Group lithologies, therefore suggesting a greater affinity to the Yaguajay* belt. The absence of anhydrite in the Yaguajay* belt and Blanquizal area could be depositional and caused by the proximity to the bank edge. However, the presence of abundant monomictic dolomite breccias, interbedded with what has been interpreted as high-saline primary dolomites, suggests that their absence could also be caused by secondary solution (Littlefield, 1952). The age of this solution ranges from the top of the Lower Cretaceous to the upper Eocene. This phenomenon might have been related to the fluid expelled from the deep basin sediments under the advancing thrust sheets; the basic igneous-volcanic province rocks are present over part of the Cayo Coco–Punta Alegre area. As already pointed out, none of the wells drilled along the north coast of Cuba west of Gulf Blanquizal III-1 has ever encountered this bank facies. This suggest that the carbonate bank province does not extend along the coast as a continuous bank farther west than the Blanquizal–Cardenas Bay area, although platform carbonates are present in Pinar del Rio. In conclusion, it appears that the Yaguajay* belt and the Blanquizal area of the coastal province show a strong affinity to the Bahamas section, with continuous sedimentation of bank carbonates (and evaporites in the lower part of the section), throughout the Upper Jurassic and the entire Cretaceous. The importance of the Mayajigua* Formation should be noted. The abundance of indigenous shallow-water fossils, the intertonguing with the Remedios* Formation, and the strong unconformity at the base suggest that it was deposited in shallow waters and, as the result of an uplift of the coastal province, accompanied with the erosion of reefs, during the Campanian – Maastrichtian. In the southeastern part of the Sierra de Meneses, the Campanian–Maastrichtian Mayajigua* Formation breccias rest directly on the Neocomian Bartolome´* Formation, with some 7700 ft (2350 m) of Aptian – Santonian section missing. In Texaco Mayajigua-1, drilled in the same general area, a minimum of 2782 ft (848 m), after dip correction, of Aptian– Albian is present above the Neocomian. In the Cayo Coco–Punta Alegre area, the shallow-water Mayajigua*

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FIGURE 71. Central Cuba: carbonate slope or scarp province.

Formation is in contact with the deep-water Casablanca Group, indicating a strong uplift. Toward the northwest, the Mayajigua is equivalent to the detrital Palone* Formation and, as will be seen later, to part of the Sagua* Formation, a similar conglomerate but apparently deposited in much deeper waters. All this is evidence for strong tectonic relief at the time of the pre-Mayajigua* Formation unconformity, in addition to the natural bathymetric relief of the carbonate banks. At present, it is difficult to estimate the possible tectonic shortening of the carbonate platform across the strike, but it must be appreciable. At least three major reverse fault zones are known in the Cayo Coco– Punta Alegre area, in ICRM Cayo Romano-1, Shell Manuy-1, and Kewanee Collazo-1, and in the Blanquizal area in ICRM Cayo Frances-5 and possibly Gulf Blanquizal III-1. The Yaguajay* fault brings the Upper Jurassic in contact with the Eocene. The total shortening, even assuming high-angle faults, could be of the order of 50,000 ft (15,000 m), or 20% of the original width of 75 km (46 mi) for the entire carbonate platform. This estimate is believed conservative because these faults could be ramps of much larger thrusts over evaporite de´collements. The carbonate platform province in eastern Cuba has certainly strong similarities with central Cuba that suggest the presence of Vin ˜as* Group-type carbonates in the Lower Cretaceous. However, it is not clear if the Camaco*, Palone*, and Remedios* Formation bank type of lithologies are present, or whether they have

been entirely replaced by the pelagic carbonates of the Casablanca Group. Furthermore, few dolomites have been reported, and those have been dated as Upper Cretaceous, so there is no indication that the outcrop section exposes the Jurassic, but this appears unlikely. Therefore, what is known about this section suggests a Cayo Coco – Punta Alegre area type of carbonate for the Aptian through Maastrichtian, but gives no indication about the nature of the pre-Aptian rocks. The low percentage of dolomite clasts in the Embarcadero Formation might be significant in that it probably represents the general composition of the bank. The presence of the Embarcadero overlain by the lower Vigia Formation is a close analog of the Sagua* overlain by the Vega*. It should be noted that, contrary to the Yaguajay* belt in Las Villas and Camaguey provinces, here, no orogenic conglomerate is associated with the Vigia Formation, as in the Rosas* and the Senado formations. On the contrary, the upper Vigia Formation represents a return to volcanic activity in a deep-water environment.

Cretaceous Carbonate Slope or Scarp The carbonate slope or scarp province consists of two belts of outcrops located between and with affinities to the Yaguajay* and the Las Villas* belts. In large part, their rocks seem to represent the foot of the slope where carbonate detritus from the shallow-water banks accumulated. These outcrops belong to the Sagua la Chica* and the Jatibonico* belts (see Figure 71).

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Sagua la Chica* Belt The belt runs south of and parallel to the Yaguajay* belt in the Remedios to Sierra de Jatibonico area. This belt is not well defined geographically. Gulf observed it only in the Sagua la Chica and Camajuani Rivers, where it is very well developed. It could be more than 45 km (27 mi) long and is closely related to, but separated from, the Jatibonico* belt. Originally, the Gulf geologists thought that it was an exceptional development of the lower – middle Eocene Sagua* Formation conglomerates in the Las Villas* belt. Further studies indicated that it contained a more complex stratigraphic sequence, time equivalent to part of the Las Villas* belt section. Unfortunately, it was not mapped in detail. In general, it appears to be a steeply south-dipping block, showing tight folds and imbrications, located between the central part of the Yaguajay* belt and the Las Villas* belt and extending from Sitiecito to south of Remedios. It can reach 3–4 km (1.8–2.5 mi) in width. It is in fault contact with the lower–middle Eocene part of the Sagua*, the San Martin* and Vega* formations that belong to the Yaguajay* belt and outcrop all along its southern flank. It appears that other authors have most certainly included it in the same unit or zone that comprises Gulf’s Las Villas* belt, although Dilla and Garcı´a (1985) created, without fully describing it, a Sagua structurofacial zone. They admit that this zone has not been studied, and they restrict it to the Tertiary. Furthermore, they do not discuss the origin of the name that is very probably Gulf’s. Pushcharovsky et al. (1988) place it in the Camajuani zone. Only Pardo (1975) has mentioned it previously in the English-language literature.

Sagua* Formation At Gulf’s type locality, the Sagua la Chica River in Las Villas province, it is 1000 ft (300 m) thick. In the same river, this section is repeated by faulting, so the total apparent thickness is 2100 ft (640 m). Hatten et al. (1958) who used the same formation name (but from a different type locality at Calabazar de Sagua), estimates 2500 ft (760 m) at other localities, but this thickness could be structurally exaggerated and must include the Sagua*, the Yaguajay* Formation, and perhaps part of the San Martin* Formation. Ortega y Ros (1937) named this unit the Santa Colona Formation, but included in it other lithologies that today are given other formation names. Dilla and Garcı´a (1985) show the Sagua and Jumagua (lower Vega*) formations as equivalent to the Vega Alta Formation that

is a tectonic breccia; this is a serious misconception. Pushcharovsky et al. (1988) show more than 8200 ft (2500 m) of a Vega Formation or ‘‘Brecha Sagua’’ described as ‘‘breccias, conglomerates, limestones, sandstones, siltstones, marls, and claystones’’ in the Camajuani ‘‘structurofacies zone,’’ which is more or less equivalent to the Las Villas* belt. Although this unit must certainly include Gulf’s Sagua*, San Martin*, and Vega* formations, the thickness appears excessive probably because of repeats. This unit is a limestone-dolomite conglomerate with angular components up to several feet in size. Like in the Yaguajay* belt, a fine matrix is very scarce compared to the number of larger blocks. It consists of a mosaic of interlocking fragments, with clean suture contacts, smaller ones perfectly filling the space between larger ones. It is extremely hard, with no porosity and prominent dogtooth weathering. The fragments consist of all older units of the Yaguajay* and Las Villas* belts. Fragments from the Yaguajay* belt are dominant. Chert fragments derived from the Cretaceous Lutgarda* and Calabazar* formations of the Las Villas* belt are abundant toward the base. The Sagua* Formation is very thickly bedded. Many depositional cycles, grading from fine to coarse grained, are visible. Chert nodules are present. In the lower part of the conglomerate section are a few thin beds of dense limestone, suggesting the Florencia* Formation of the Jatibonico* belt. The fauna can be divided into three groups; the dense limestones in the lower part of the section contain common Orbitolina sp., Dictyoconus walnutensis, and Coskinolinoides sp., suggesting an Aptian–Albian age. Higher in the section, a fauna consisting of Globtruncana lapparenti sl., Vaughanina, Orbitoides sp., and Sulcoperculina sp., and Globigerina cretacea sl., identical with that of the Mayajigua* Formation, appears, suggesting a Maastrichtian age. Dense limestone interbeds containing Globigerina cretacea, Gumbelina, and Globotruncana sp. also exist. Finally, toward the upper part of the section, the typical lower–middle Eocene faunas of Discocyclina spp., Asterocyclina spp., Globorotalia spp., and spinose globigerinas are present. Although many of the fossils are found reworked into the conglomerates, the characteristic associations and the dating of the dense limestones interbedded with the conglomerates leaves little doubt of the presence of three ages of beds (Aptian–Albian, Maastrichtian, and lower–middle Eocene) separated by unconformities or hiatuses. However, the breaks are undetectable, and there is no way to subdivide the unit on lithologic grounds.

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Upward, the Sagua* Formation is gradational into the San Martin* Formation. The base was not observed; however, Pushcharovsky et al. (1988) show it overlying directly onto Berriasian to Barremian sediments identified as the Margarita and Paraiso formations. It would be interesting to determine if these are outcrops of Mabuya* or Capitolio* Formation. The lower Aptian – Albian part of the Sagua* Formation has been observed only in the Sagua la Chica belt, although it has great similarities to the ageequivalent Florencia* Formation in the Jatibonico* belt and the Calabazar* Formation of the Las Villas* belt, which also contain numerous detrital limestones with identical fauna as components. The middle part is very similar to and correlates with the Mayajigua* Formation of the Yaguajay* belt and coastal province, although it appears to have been deposited in deeper waters. It is also similar to the deep-water calcarenites of the Lutgarta* Formation of the Las Villas* belt. The lower–middle Eocene part is very widespread and occurs in the Yaguajay* belt from the town of Remedios, in Las Villas, to Gibara in northern Oriente. It has been found in the Las Villas* belt from the subsurface in northern Matanzas to Loma Camajan in Camaguey. The possible origin of this rather unique rock will be discussed later in this study.

San Martin* Formation In this belt, the San Martin Formation is present in its typical development.

Vega* Formation The San Martin* grades into the Vega* Formation, which, in this belt, is characterized by a large development of coarse, poorly sorted polymict conglomerates in its upper member (Rosas* Formation).

Jatibonico* Belt This belt is limited to the northeastern part of the Sierra de Jatibonico. It runs south of and parallel to the Yaguajay* belt. It represents a distinct stratigraphic section with affinities to both the Yaguajay* and Las Villas* belts. It is a south-dipping fault block bounded to the north by the Jatibonico* fault and to the south by the Las Villas* fault (see Figure 72). Other authors have included this belt in the Remedios zone of Ducloz and Vaugnat (1962), Zulueta unit of Hatten et al. (1958), and Remedios structurofacies Zone of Pushcharovsky et al. (1988). Shopov (1982) called it the Jatibonico subzone of the Camajuani zone.

Guani* Formation This unit consists of at least 1300 ft (400 m) of massive dolomites identical with those of the Yaguajay* belt. The base is unknown, and it is conformably overlain by the Mabuya* Formation.

Mabuya* Formation It consists of 2300 ft (700 m) of thin-bedded brown to yellow argillaceous limestone with interbedded yellow weathering claystone and brown crystalline dolomite. The limestone is occasionally pseudo-oolitic and commonly dolomitized. At the top is a sequence of interbedded coarse dolomite conglomerate and medium- to coarse-crystalline banded dolomite 350 ft (107 m) thick. It is overlain with a possible unconformity or hiatus by the Florencia* Formation. Toward the top of the formation, Choffatella sp. and Pseudocyclammina sp. have been found. At the base, associated with the oolitic beds, Calpionella cf. elliptica, Calpionella alpina, Calpionella undelloides, and Nannoconus spp. are present, showing definite openwater pelagic influence. The fauna indicates an age ranging from Upper Jurassic to Aptian. It is equivalent to the Cayo Coco* Formation of the coastal province, the Bartolome´* and, possibly, the lower Palenque* formations of the Yaguajay* belt, and the Capitolio* Formation and upper Trocha* Group (Caguaguas* and Jaguita* formations) of the Las Villas* belt. Lithologically, it definitely shows an intermediate facies between the Yaguajay* and Las Villas* belts.

Florencia* Formation The Florencia* Formation (not related to the Florencia Formation of middle Eocene age described by Hatten et al., 1958) consists of 900 ft (274 m) of white to gray-brown, dense to thin-bedded calcarenites, with interbeds of coarse limestone sharpstone conglomerates. Abundant silicified megafossils are concentrated in layers. Occasional dolomitic limestone beds exist. Near the top, a 120-ft (37-m) very coarse sharpstone conglomerate exists devoid of megafossils. The finer grained units contain rock-forming Nannoconus spp., Globigerina cretacea sl. var., Orbitolina sp. cf. O. texana–O. concava, and miliolids, suggesting an Aptian to middle Albian age. As mentioned before, this formation has great similarities to the lower part of the Sagua* Formation of the Sagua la Chica* belt. It appears to be unconformably overlain by the Mayajigua* Formation, although some structural complications are observed.

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FIGURE 72. Stratigraphic section: Jatibonico* belt.

Mayajigua* Formation

San Martin* Formation

The Mayajigua* Formation is present in its typical development, but with very coarse limestone and dolomite conglomerates. It contains very abundant Campanian – Maastrichtian orbitoids. It is 600 ft (185 m) thick and appears to grade into the lower – middle Eocene part of the Sagua* Formation with no sign of unconformity, although the Paleocene has not been recognized.

It is present in its characteristic development with a marked increase in pelagic forms.

Sagua* Formation Only the lower – middle Eocene part of the Sagua* Formation is present and grading into the overlying San Martin* Formation.

Cretaceous Carbonate Slope or Scarp Discussion The Jatibonico* and Sagua la Chica* belts are very significant for the paleogeographic and paleotectonic reconstruction of Cuba. They have not received the attention they deserve. The Jatibonico* belt shows transitional sedimentation during the Upper Jurassic and pre-Aptian Cretaceous between the Yaguajay* and the Las Villas* belts and continuous, mostly coarse, clastic carbonate sediments from the Aptian to lower–middle Eocene.

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The Sagua la Chica* belt is also characterized by continuous coarse clastic, dominantly carbonate sedimentation, which lasted from the Aptian –Albian to the early – middle Eocene. Although no break in a continuous well-exposed section is observable, no Cenomanian to Santonian or Paleocene faunas have been identified. These coarse deposits might represent the Yaguajay* belt carbonate bank talus, but this interpretation leaves the common presence of pelagic limestones and chert fragments originating from the deeper water sediments of the Las Villas* belt to the south unexplained. Perhaps the Sagua la Chica* belt is evidence for a major fault, lasting from the Aptian to the lower–middle Eocene, responsible for the carbonate bank margin (Hatten et al., 1958). All evidence points toward the Sagua* being a deepwater deposit, although most of the reworked faunas are of shallow-water origin. Perhaps the deeper water fragments are of a tectonic nature, such as contemporaneous active rifts, whereas the shallow-water ones were part of a conventional talus. The argument against this is that, with the exception of the Mayajigua* Formation, components of a typical reef (corals, algae, mollusks) are relatively infrequent; most of the debris appears to have been derived from already solidified back-reef material as if the bank was being tectonically destroyed. The original distance across the strike represented by these two belts and the horizontal displacement of the Sagua la Chica* and Jatibonico* faults is impossible to estimate.

Jurassic Platform to Cretaceous Deep Basin The Jurassic platform to Cretaceous deep basin province comprises three belts, Las Villas*, Placetas*, and Cifuentes*, each representing a characteristic succession of lithologies. These belts may have been brought into proximity by major thrust faults, but their present outcrops are probably caused by later generations of faulting that, in large part, mask or distort the original ones. For this reason, the stratigraphic definition of the belts has been followed. These three belts are believed to be representative of part of a miogeosyncline as originally defined by Marshall Kay, that is, devoid of volcanic activity. As will be seen later, sedimentation was in a shallowwater carbonate platform until the early Tithonian, at which time sedimentation could no longer keep pace with a probably accelerated subsidence. There was no major contribution of silicate clastics until the lower– middle Eocene diastrophism. The influence of volca-

nism was practically nonexistent except in the southernmost part. This is the area where the ‘‘belt,’’ ‘‘unit,’’ ‘‘zone,’’ etc., nomenclature has been the most confused. Gulf subdivided the platform to deep basin province into three belts and five unnamed informal subdivisions. Most subsequent authors saw no need to have more than two subdivisions. Three belts provide the best basis for unraveling the geologic history of Cuba. As will be seen below, the Las Villas* and Cifuentes* belts represent two facies extremes, whereas the Placetas* belt is transitional.

Las Villas* Belt In the province of Las Villas, it strikes essentially parallel to the previous belts and outcrops almost uninterruptedly for 175 km (108 mi) from south of the Bahia de Santa Clara in northern Las Villas to the south end of the Sierra de Jatibonico in northwestern Camaguey. It is limited to the south by a line running through Rancho Veloz, Cifuentes and Mata, Calabazar de Sagua, Vega Alta, Camajuani, slightly south of Zulueta, and parallel to the south edge of the Sierras de Bamburanao and Jatibonico, to Los Barriles. To the west, it has been identified in the subsurface as far as Via Blanca, near Habana. Two windows in the Cifuentes* belt show the Las Villas* belt: the Yabu window 7.5 km (4.6 mi) west of the town of Cifuentes, and the Fidencia anticline 12 km (7.5 mi) south-southeast of the town of Camajuani. In the province of Camaguey, the Las Villas* belt consists of limited outcrops immediately south of the northwestern end of the Sierra de Cubitas and in the northern half of the Sierra Camajan (see Figure 73). This belt was defined by G. Pardo in 1952, who redefined it to exclude the Sagua la Chica* belt (Pardo, 1954). Note that P. Ortegas y Ros described accurately its essential stratigraphy in 1937, but because of the obscurity of the publication, the work remained essentially unknown until the middle 1950s. The following are highlights of what happened to the Las Villas* belt since then: (1) Hatten et al. (1958) named a feature essentially equivalent of the original 1952 Las Villas* belt, the Zulueta tectounit; (2) Ducloz and Vuagnat (1962) named it the Camajuani zone; (3) FurrazolaBermudez et al. (1963) used the name Las Villas structural-facies zone; (4) Meyerhoff and Hatten (1968) named it the Camajuani zone; (5) Kniper and Cabrera (1974) named it the San Felipe zone; (6) Dilla and Garcı´a (1985) named it the Camajuani subzone

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FIGURE 73. Central Cuba, Las Villas* belt.

of the Las Villas structurofacies zone; and (7) Hatten et al. (1988) named it the Zulueta unit. In Pushcharovsky et al. (1988), it is called the Camajuani structurofacies zone. The amazing thing was that all this name changing was done in the absence of any new information and based on mid-1950 data. This could be amusing if each author had not modified the definition, so that a translation is impossible from the literature alone. For this reason, the Pardo, 1954, definition of the belt will be maintained, and in this study, it will be named the Las Villas* belt. In 1954, Gulf used an informal local subdivision named the ‘‘Las Villas* belt southern facies’’ to describe a lithologic sequence intermediate between the Las Villas* and the Placetas* belt.

Las Villas Province Area The Las Villas* belt is characterized by the most complete and fossiliferous Jurassic to lower – middle Eocene sedimentary section in central Cuba. It was used by Gulf as its type section for the pre–upper Eocene of central Cuba. It can reach up to 9.5 km (5.9 mi) in width without counting the windows. It has been recognized in the subsurface along the north coast from the Bahia de Cardenas in Matanzas to La Habana. The Las Villas* belt can be subdivided along its length into a northeastern and a southwestern half by important facies differences. The type localities for most of the formations are located in the Quemado de Gu ¨ ines anticlinorium in

northern Las Villas. The section will be described below (see Figure 74). Trocha* Group.—The Trocha* Group includes several Upper Jurassic–related carbonate and chert lithologies. The lower part of the group was deposited in shallow water, although the presence of some radiolaria indicate open waters. It outcrops mostly in the southwestern half of the belt. The total thickness is at least 2800 ft (850 m). This unit was named the Trocha Formation by Ortega y Ros (1937). In Pushcharovsky et al. (1988), 1310 ft (400 m) of an Upper Jurassic – Tithonian Trocha Formation are present. Although the thicknesses do not match, it is believed to be synonymous with Gulf’s Trocha* Group. In 1952, Gulf geologists divided it as follows: Hoyo Colorado* Formation. —The Hoyo Colorado* Formation consists of a minimum of 2100 ft (640 m) of dense, gray to light gray, in places pseudo-oolitic, limestone and light brown, medium-bedded, finecrystalline secondary dolomite. Occasional red and brown secondary cherts exist. This unit is medium to thick bedded. In the upper part, the fauna is similar to the overlying Jaguita* Formation, and in its lower part, only unidentifiable radiolaria have been found. Based on the fossils and its stratigraphic position, it is considered of possible Kimmeridgian to lower Tithonian age. It definitely seems to have been deposited under shallow-water bank conditions, with the exception of the radiolaria fauna found at the base.

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FIGURE 74. Stratigraphic sections: Las Villas* belt.

It is partly equivalent to the Guanı´* Formation of the Yaguajay* belt and the Cayo Coco* Formation of the Cayo Coco –Punta Alegre area. The base has not been observed, but it could have been originally underlain by the Punta Alegre* or the San Adrian Formation. The present base is very likely to be a fault. It is conformably overlain by and grades into the Jaguita* Formation. Jaguita* Formation. — The Jaguita* Formation consists of 1400 ft (425 m) (some structural repeats are possible) of cream orange, brown gray and gray, pseudo-oolitic to oolitic limestones, interbedded with dense radiolarian limestones occasionally stained

by iron and manganese oxides. This formation is commonly medium to very thick bedded. The fauna consists of Pseudocyclammina sp., Coscinoconus sp., Nautiloculina sp., Lenticulina sp., and radiolaria. Aptychi and ammonites are locally abundant. R. Imlay (1954, personal communication) identified the following ammonites: Pseudolissoceras zittelli, Lithoplites caribbeanus, Protancyloceras hondenses, and Microacanthoceras sp. In addition, several microfossils exist incertae sedis, such as Globochaetes alpina, Eothrix alpina, and Saccocoma spp. Favreina has been found in this formation in Cuban Gulf Hicacos-1. These assemblages indicate a middle Tithonian age and show a

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strong affinity to those described in the Upper Jurassic of the Tethys region. The facies (and microfacies) are also very similar. The fauna is mostly shallow water; however, the presence of radiolaria in dense limestones indicates a definite deepening of the water, and the oolites, as well as the shallow-water assemblage, could well be reworked from nearby banks. This formation is believed to be in part equivalent to the Guanı´* and lower Bartolome´* formations of the Yaguajay* belt and in part to the Cayo Coco* Formation of the Cayo Coco–Punta Alegre area. It is comformably overlain by the Caguaguas* Formation. Caguaguas* Formation.—It consists of 375 ft (115 m) of dense, medium-bedded, gray carbonaceous limestone interbedded with medium-bedded banded limestone. The banded limestone has flesh pink to buff porcelaneous bands alternating with carbonaceous, wavy laminated, gray, dense bands. The wavy laminae are commonly orange colored, and the whole formation on weathering is stained by limonite and manganese oxide. In fresh exposures, the color is black. The Caguaguas* Formation appears to be a transition between the Jaguita* and the overlying Capitolio* Formation. The fauna consists of abundant radiolaria, C. elliptica, and C. alpina. The age is considered upper Tithonian. The Caguaguas* Formation represents a marked water deepening compared with the bank carbonate environment of the Hoyo Colorado* Formation. It is equivalent to the lower Mabuya* Formation of the Jatibonico* belt, the lower Bartolome´* Formation of the Yaguajay* belt, and part of the Cayo Coco* Formation of the Cayo Coco – Punta Alegre area. It grades into the overlying Penton* Group. Penton* Group. —This group was described and named by Ortega y Ros (1937). It consists of 1100 ft (335 m) of medium-bedded buff dense limestone with wavy orange laminations and black and brown interbeds of chert and some secondary silicification. In the southwestern Las Villas* belt, it contains calcarenites and calcirudites. It is subdivided into the following formations. Capitolio* Formation. —The Capitolio* Formation consists of 800 ft (245 m) of buff, dense, biomicrite, with thin, yellow-orange, wavy laminae, interbedded with brown and black thin-bedded banded vitreous chert. Most of the chert is a secondary silicification of limestone (the limestone fabric can be seen in thin sections) containing abundant radiolaria that are now replaced by calcite. The limestone layers are thick and flat-bedded, but commonly split into set plates parallel to the bedding. Aptychi are common along the

surface of these plates. This unit outcrops along the northeast part of the Las Villas* belt. It grades into the overlying Ramblazo* Formation. Hatten et al. (1958) describe 1178 ft (359 m) of a Margarita Formation that appears to be at least partly synonymous with the Capitolio* Formation. Pushcharovsky et al. (1988) show in the Zulueta zone 985 ft (300 m) of biomicrites with little chert of Beriassian – Hauterivian age called the Margarita Formation and 820–985 ft (250–300 m) of stratified limestones (biomicrites) with interbedded cherts of Hauterivian – Barremian age called the Paraiso Formation. These two units appear to be synonymous with the Capitolio* Formation. In addition to aptychi and abundant unidentifiable radiolaria, it contains Nannoconus steinmanni and common Calpionellites darderi, Tintinosporella carpathica, Calpionclla elliptica, and Calpionellopsis oblonga. The Nannoconus is rock forming and, together with the abundant radiolaria, indicates a deep, open-water environment. It is considered of Neocomian age. The conspicuous aptychi are the reason for formerly calling this type of lithology the ‘‘Aptychus Formation.’’ Ramblazo* Formation. — The Ramblazo* Formation consists of 340 ft (104 m) of medium-bedded but very thin-plated, rust-laminated to white dense limestone, similar in microstructure to that of the Capitolio* Formation, but with fewer wavy laminae. Thin stringers of dark-black, waxy chert are present and are one of the distinguishing features of the formation. Some calcirudites with a somewhat argillaceous matrix are present. Thin interbeds of shale that weather white and form a faint white band in air photographs are common throughout the formation. The Ramblazo* Formation has a very characteristic aspect when exposed on roads; each bed separates into a book of very fine plates because of the presence of argillaceous partings. It contains abundant radiolaria and rock-forming Nannoconus steinmanni and Nannoconus spp. Abundant Orbitolina cf. texana exists in the calcarenites. The presence of a shallow form such as Orbitolina in calcarenites interbedded with deep-water sediments indicates the presence of turbidites, probably originating from the carbonate banks to the north. This situation is repeated later in the section. The age is considered Aptian. The Ramblazo* Formation is equivalent to the upper part of the Sabanilla* Formation. It is comformably overlain by the Calabazar* Formation. Hatten et al. (1958) probably include the Ramblazo* Formation in the lower part of the Alunado* Formation. It might be

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included in the Paraiso Formation in Pushcharovsky et al. (1988), but there is no mention of an Aptian unit. Sabanilla* Formation. — The Sabanilla* Formation consists of 500 – 800 ft (150–250 m) of interbedding of Capitolio*-type limestones and cherts with calcarenites, commonly fine grained but sometimes becoming limestone conglomerates. The matrix is conspicuous and consists of a yellow to gray dense, structureless limestone. The fragments are mainly derived from the underlying Jaguita* and Caguaguas* formations, although some are derived from the Capitolio* Formation. It should be pointed out that no components other than carbonates are present. This unit is present in the southwestern half of the Las Villas* belt, and the size of the fragments increases southward, along with the percentage of detrital beds. Along the southwestern edge of the Las Villas* belt, detrital beds completely replace the Capitolio* lithology. The origin of this unit is certainly caused by an unconformity within the Capitolio* Formation; as from north to south, the Sabanilla* Formation is characterized by (1) thin calcarenites interbedded with the Capitolio* lithology, (2) dominantly detrital beds resting on the Capitolio* Formation, and (3) dominantly detrital beds, with components becoming conglomeratic in size, resting on the Caguaguas* Formation. A study of the detrital bed components indicates the southern origin of the sediments. Hatten et al., 1958, mentions the presence of a Tithonian Sabanilla Formation, but no description is given. The fauna is characterized by Coskinolinoides sp., Cuneolina sp., miliolids, Robulus sp., Nannoconus steinmanni, Calpionellites darderi, Tintinnopsella carpathica, Calpionella elliptica, and Calpionellopsis oblonga. This fauna indicates two disparate environments, shallow bank and pelagic, possibly deep water. The upper part of this unit is also the lateral equivalent of the Ramblazo* Formation and is comformably overlain by the Calabazar* Formation. The character of the Sabanilla* Formation suggests Neocomian rifting. Obviously, an area south of the Las Villas* belt either failed to subside or, after an initial subsidence in the early stage of Capitolio* deposition, was uplifted. The nature and mix of the components in the Sabanilla* Formation suggests a steep scarp with fragments of Jaguita*, Caguaguas*, and already deposited Capitolio* formations dropping into a deep basin. The situation was a forerunner of the fault system that later would be responsible for the Sagua la Chica* belt. The shallow-water Aptian fauna could have come from either the north or the south. This fault must have become inactive in the late Aptian,

the time of the earliest Sagua* development, because the Calabazar* Formation conformably overlies both the Ramblazo* and the Sabanilla* formations. Malpaez* Group. —Hatten et al. (1958) named the lower 450 ft (135 m) of this group the Alunado Formation. This group includes several interbedded calcarenites, limestone conglomerates, dense argillaceous white limestones, powdery radiolarites, cherts, and shales. The fact that it contains what appears to be a significant regional break in sedimentation during the Coniacian could be an argument to restrict it to the lower two units. The thickness of the group ranges from 600 to 1000 ft (185 to 300 m). This group is subdivided into the following formations. Calabazar* Formation.—It consists of 230 ft (70 m) of interbedded white to very light-gray weathering dense limestone and waxy black and steel-gray thin cherts. Medium- to coarse-grained calcirudites exist. The bedding is thin, but some medium beds are present. In places, intervals of brown thin-bedded, sometimes thick, vitreous chert and white-weathering, darkgray shale (with no limestones present) are observed. This formation is typical of the Las Villas* belt. In Pushcharovsky et al. (1988), 330 ft (100 m) of limestones (calcarenites and biomicrites), cherts, and breccias (conglomerates) of Albian–Cenomanian age called the Mata Formation exist. This unit must certainly be synonymous with the Calabazar* and overlying Mata* Formation. The lower part contains abundant Nannoconus spp., whereas toward the upper part, it contains abundant Globigerina cretacea sl., Rotalipora appenninica, and Guembelina sp. Radiolaria are abundant, and a calcarenite at the base of the formation contains detrital Orbitolina cf. texana. The age is believed to range from the late Aptian through the Cenomanian. The environment is definitely deep water, but an influx of turbidites brings in shallow-water detritus, most probably from the north. It grades into the overlying Mata* Formation. To the south, the upper part of the Calabazar* becomes equivalent to the entire Mata* Formation. Note that the Calabazar* and Mata* formations have strong lithologic and paleontologic similarities with the Casablanca Group of the Cayo Coco–Punta Alegre area and are generally its equivalent. Mata* Formation. — It consists of 150–220 ft (45– 70 m) of interbedded calcarenites, dense limestones, and cherts. In the lower part of the formation are thinto medium bedded, buff to orange, dense limestones

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interbedded with medium- to coarse-grained heterogeneous calcirudites. In some places, these calcirudites contain chert nodules and, in others, are completely silicified. In its upper part, opaque dense brown and gray cherts consist of silicified radiolarites. The original radiolarite can be seen as a yellow-brown powdery coating on the upper surface of the cherts; it is made entirely of perfectly preserved radiolaria. This unit is distinguished from the underlying Calabazar* Formation by the presence of silicification and absence of black waxy chert. This unit as shown in Pushcharovsky et al. (1988) includes the Maastrichtian Lutgarda Formation. In addition to the abundant radiolarian fauna, it contains Globigerina cretacea sl. and Rotalipora appenninica. It is considered late Cenomanian and Turonian in age. The calcarenites contain an abundant reworked Lower Cretaceous and Upper Jurassic fauna. As suggested by the thickness changes, the weathered appearance of the upper Mata*, the abundant manganese staining at the base of the Lutgarda*, and the regional absence of Coniacian fossils, it is believed to be overlain with disconformity, or slight unconformity, by the Lutgarda* Formation. However, no evidence exists of a shallower-water environment. Lutgarda* Formation. — At the type section, the Lutgarda* Formation consists of 180 ft (55 m) of thinto medium- bedded, heterogeneous calcarenites and calcirudites, bright red and brown chert as beds and nodules, very fine detrital to porcelaneous white limestone, greenish-blue clay, and a characteristic sugarywhite limestone consisting exclusively of small broken rudist fragments, which give it a sparkling crystalline appearance. At the base of the formation, the limestones are strongly stained with manganese, giving them a pink to black color. This unit is shown in Pushcharovsky et al. (1988) as the Maastrichtian Lutgarda Formation. In other outcrop sections, as much as 660 ft (200 m) have been measured, but this extra thickness could be caused by isoclinal folding that, in the Las Villas* belt, becomes common toward the upper part of the section. For the same reason, a question of whether more than one Rudist fragment bed are observed exists. The Lutgarda* Formation is very persistent throughout the Las Villas* belt, but thins southwestward to 20 ft (6 m), across the belt. This thinning results in a spotty outcrop pattern along the southern margin of the belt. The indigenous fauna is very scarce. Only Globotruncana lapparenti sl., Globigerina cretacea sl., and

Pseudorbitoides sp. fragments are found. The very great abundance of rudist fragments suggests that large rudist colonies were living nearby. Other, probably reworked, fossils are abundant such as Cuneolina sp., Coskinolina sp., Dictyoconus sp., Nummoloculina sp., and Dicyclina sp. The age is Santonian through Maastrichtian. This formation appears to grade into the lower – middle Eocene conglomerates of the Sagua* Formation, despite the fact that no Paleocene fauna has been recognized. It correlates with the middle part of the Sagua* Formation in the Sagua la Chica* belt, the Mayajigua* Formation of the Jatibonico* belt and Cayo Coco–Punta Alegre area, and the Remedios* and Palone* formations of the Yaguajay* belt. The Malpaez* Group, therefore, represents a deepwater sequence that ranges from the end of the Aptian to the end of the Cretaceous, and perhaps into the Paleocene, and received progressively increasing amounts of detrital material in the form of turbidites from the carbonate platform to the north. The entire section shows a total lack of silicate clastics. The overlying lower –middle Eocene part of the Sagua* Formation conglomerates represents the culmination of this process. Pszczo´lkowski (1986b) has suggested that the Maastrichtian detrital turbidites were originated by a catastrophic event at the end of the Cretaceous. The Malpaez* Group section indicates that the turbidite deposition was a continuous process of long duration. Sagua* Formation. — This unit is present along the entire length of the northeastern half of the Las Villas* belt, where it is seldom more than 100 ft (30 m) thick and is of lower–middle Eocene age. It thins abruptly across the strike and is either a few feet thick or disappears completely before reaching the southwestern edge of the belt. This formation grades southward into the Camajuani* Formation. Upward, it grades into the overlying San Martin* Formation. Camajuani* Formation. — It is the southern facies of the Sagua* Formation and ranges in thickness from ±20 to 0 ft (±6 to 0 m). It is characterized by a great abundance of black, brown, and red tabular chert clasts derived from the older Malpeaz* Group. Like the Sagua* Formation, it appears to grade into the overlying San Martin* Formation. It is interesting to speculate why the downdip featheredge of the Sagua* Formation would contain such a high concentration of chert. One possibility could be the reactivation of an old source of sediments to the south of the Las Villas* belt, as suggested by the underlying Sabanilla* Formation clastics. Another

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could be the concentration of low-density material, such as silica, at the base of a submarine slope. At any rate, the underlying Calabazar* cherts had to be eroded. Another possibility is that if the cherts were solidified penecontemporaneously with sedimentation in a marly nannoplankton matrix (like chert nodules in chalk), they might have been loosened and reworked by submarine currents. San Martin* Formation. — In the type section, it consists of 220 ft (70 m) of tan, fine to coarse calcarenites with abundant igneous grains. It is interbedded with pebble conglomerates containing abundant chert fragments and with a dull light-gray argillaceous limestone that typically shatters into splinters. The Hatten et al. (1958) name, Gonzal Formation, appears to be synonymous with the San Martin* Formation. As already mentioned, in the Las Villas* belt, as well as in the belts to the north of it, the San Martin* Formation represents the first influx of igneous detritus from the south. It is transitional to the overlying Vega* Formation. The San Martin* Formation contains a rich foraminiferal fauna characterized by Globorotalia sp., Tremastegina sp., Baggina sp., Discocyclina sp., Planorbulina sp., Dyctyoconus sp., and spinose Globigerina sp. Radiolaria are abundant, and coccolithophors and discoasters are rock forming. The age is lower –middle Eocene. This formation is present all along the Las Villas* belt and can reach 1000 ft (300 m) in thickness, although this figure might be tectonically exaggerated. As already mentioned, it is present in the Yaguajay*, Sagua la Chica*, and Jatibonico* belts. Vega* Formation.—At the type section (ChambasTamarindo road, Camaguey) in the southeastern end of the Las Villas* belt (thrusted over the Jatibonico* belt), 3300 ft (1006 m) of this clastic, igneous-derived unit exists. The greatest percentage of fragments is from basic igneous rocks. It is divided into two members, as described below. Lower Member. —The lower member consists of 300 ft (91 m) of calcareous shales, thin-bedded dull-white limestones, and occasional calcareous, igneous-derived sandstones. It is distinguished from the upper member by its calcareous content. Hatten et al. (1958) named the Jumagua Formation, which appears to be synonymous with the lower member of the Vega*. Based on the presence of Truncorotalia cf. aragonensis, Globigerinoides mexicana, and Hantkenina aragonensis, they assign it to the middle Eocene. The unit contains a rich pelagic fossils consisting of foraminifera, radiolaria, and sometimes rock-forming

discoasters and cocolithophors. The age is lower – middle Eocene. This unit is obviously a deep-water turbidite deposit. Upper Member.— The upper member consists of 3000 ft (915 m) of graywacke sandstone, shales, and conglomerates. The sandstones and conglomerates are poorly sorted and commonly thick bedded. The shales are commonly silty and thin bedded. In the coarser conglomerates, the boulders can reach several feet in diameter and commonly consist of various igneous rocks, although limestone and other sedimentary clasts are present. Sometimes, the boulders bleed oil when broken. The general color of the formation is gray when fresh, but the rock weathers to rust brown. The lower part of the upper member is almost exclusively shale and finer grained sandstones, whereas the coarser clastics are toward the top. This member is noncalcareous. The very coarse wildflysch part of the upper member was called by Gulf the Rosas* Formation. This was done because in many instances, it is only the Vega* Formation lithology that can be seen along fault zones. The upper member is essentially barren of organisms except for a few detrital foraminifera and radiolaria. The age is considered lower – middle Eocene because of its stratigraphic position and because it contains fragments of all older units. The Hatten et al. (1958) name, Florencia Formation, appears to be synonymous with the Vega* upper member. The Vega* Formation is certainly included in the Vega Formation in Pushcharovsky et al. (1988), together with the San Martin* and Sagua* formations. It also describes a Senado Formation in the Sierra de Cubitas, which is certainly synonymous with the upper Vega* or Rosas* Formation. The Vega* Formation is widely distributed all along the Las Villas* belt either in synclines or caught in fault planes, where it appears to form the main lubricant. This is especially true in the major Las Villas* fault. For this reason, in addition to poor exposures, it is very difficult to find and measure reliable sections. The Vega* Formation represents a typical flysch deposited in deep waters ahead of the advancing allochthonous basic igneous-volcanic province thrust front. The unit is caught in the deformation and faulting of the more autochthonous units ahead of the thrust plates. As previously mentioned, the Vega* was also deposited over the Yaguajay* (Remedios – Sierra de Jatibonico and Cubitas areas), Sagua la Chica*, and Jatibonico* belts.

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Las Villas* Belt Southern Facies This informal belt forms a narrow band south and adjacent to the Las Villas* belt. It extends for some 45 km (27 mi) from near the town of Camajuani to the town of Iguara´. This belt is lithologically similar to the Las Villas* belt, but is differentiated by the absence of Jurassic and lower–middle Eocene rocks and a slightly different facies in the Maastrichtian. The oldest rocks exposed are a thick (±3000 ft; ±1000 m) development of the Lower Cretaceous Capitolio* and Sabanilla* formations. However, the Sabanilla* Formation is not as characteristically developed, and the conglomerates and detrital limestones do not contain fragments as coarse as in the southern part of the Las Villas* belt to the north. This suggests that the highs responsible for the detritus were linear and relatively narrow as would be expected of fault blocks located between the Las Villas* and the Las Villas* belt southern facies. The succession continues with the Ramblazo* and Calabazar* formations, the last showing an increase in the frequency of red and brown-weathering cherts and shales. The Upper Cretaceous Mata* Formation is occasionally present but not as well developed as in the Las Villas* belt. The Lutgarda* Formation is well represented and apparently thicker than in the Las Villas* belt but has some intervals of the dense, pink porcelaneous limestones found in the Corona* and Amaro* formations of the Placetas* and Cifuentes* belts respectively. In addition, this unit contains a rich pelagic assemblage with Globigerina cretacea sl., Guembelina sp., and Globotruncana lapparenti sl. Little is known about younger rocks. The Sagua* and its equivalent, the Camajuani* formations, are definitely missing because there are scattered occurrences of San Martin* Formation overlying the Lutgarda* Formation. It appears that the lower – middle Eocene was, in large part, not deposited, and whatever was laid down was destroyed by the diastrophism. Central Camaguey Area.—In central Camaguey, the Las Villas* as well as the Cifuentes* belt lithologies outcrop in small faulted windows in the Domingo* sequence, south of the Sierra de Cubitas Yaguajay*. In Pushcharovsky et al. (1988), these lithologies are shown as outcrops of the Esmeralda complex, consisting of detrital and calcarenites, cherts, and argillaceouscalcareous slates of Upper Jurassic through Albian age. The Las Villas* belt lithologies also outcrop in the northern third of the Sierra de Camajan. There, they

are in fault contact with the Cifuentes* belt to the south. In Pushcharovsky et al. (1988), only the Veloz and Carmita formations are shown. The entire feature is surrounded by Domingo* sequence rocks. Northern Cuba Area.—In the Habana and Matanzas provinces, the Las Villas* belt is found only in the subsurface, underlying the basic igneous-volcanic province (see Figure 75). Figure 76 is a correlation chart of the northeastern terrane units recognized in northern Cuba. According to Kuznetsov et al. (1985), who call the Las Villas* (or Mogotes?) belt equivalent the para-autochthonous section, the following units as shown in Figure 77 have been recognized. Upper Jurassic.— Two wells, one in the Boca de Jaruco and the other in the Varadero field, encountered a carbonate and terrigenous section containing Cadosina sp. and Globochaetes alpina that suggests the Francisco Formation. Above this unit are micritic, partially dolomitized, oolitic, and sometimes black limestones with shale partings, which contain Calpionellites darderi, Chitinoidella cubensis, Chitinoidella bermudezi, Favreina sp., Saccocoma sp., Cadosina sp., Calpionella alpina, aptychus, and ammonites and are identified as the Artemisa Formation (A. Pszczo´lkowski [2006, personal communication] considers it an error). Although the measured thickness shown is greater than 4000 ft (1200 m), the real thickness is believed to be not greater than 650 ft (200 m) because of high dips. It should be noted that the Varadero field is the easternmost reported occurrence of terrigenous clastics of Oxfordian age in northern Cuba. This supports the postulated Jurassic age of the exotics in the San Adrian diapir. Cretaceous.—Most of the information on the subsurface is provided by the agencies responsible for drilling for petroleum in Cuba (ICRM, EPEP). They obviously follow the type of geological nomenclature initiated in the former Soviet-era; that is, age determinations based on fossils, not the lithostratigraphic nomenclature used by the U.S. Geological Survey and the Cuban Academy of Sciences. It therefore requires a certain amount of interpretation to correlate the units with the well-established lithostratigraphic sections. Neocomian: — This part of the Lower Cretaceous has been recognized in many wells of the Boca de Jaruco and Varadero fields. Berriasian–Valanginian:—The lower part of the section consists of micritic, cherty limestones with clayey partings correlated with the Sumidero (Capitolio*) Formation. The upper part consists of thin-bedded micritic limestones, marls, and shales that have quartz, feldspars, mica, pyrite, sulfur, and organic matter along

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FIGURE 75. North-central terrane, northern Cuba, generalized geologic map.

the bedding planes. It has been correlated to the Polier (Constancia*) Formation. The fauna consists of Nannoconus sp., Calpionellites darderi, Tintinopsella spp., Calpionellopsis spp., and Remaniella sp. It is estimated to be up to 1300 ft (400 m) thick. Hauterivian–Barremian:—The Hauterivian–Barremian consists of micritic, bituminous limestones with a few shales provisionally considered similar to the Lucas Formation. The fauna consists of Nannoconus spp., radiolaria, aptychus, and ammonites. The Neocomian is believed to be unconformably under the Campanian – Maastrichtian in the Boca de Jaruco, Via Blanca, and Yumuri fields and the middle– upper Paleocene in the Varadero field. Kuznetsov et al. (1985) compares this section to the La Esperanza– Martin Mesa zone, although the considerably reduced thickness, the lesser grade of dolomitization, the smaller quantity of terrigenous material, and the increase in carbonates and cherts indicate a more offshore zone of the miogeosynclinal deposits or to a subzone within the limits of the Las Villas* belt. Aptian–Turonian:—This interval of time is poorly represented, and Kuznetsov et al. (1985) consider it to be only remnants preserved in synclines under the Campanian unconformity.

Aptian–Albian:—The Aptian–Albian interval consists of micritic, cherty limestone containing a fauna of Hedbergella sp., Ticinella sp., Praeglobotruncana sp., and Nannoconus sp. It is equivalent to the Calabazar* Formation. It has been recognized in the Yumuri and Colorados fields, where it reaches 1300 ft (400 m) in thickness. Cenomanian – Turonian: — The Cenomanian – Turonian interval is shown as calcarenite containing Rotalipora sp., Hedbergella sp., and Shackoina sp. It is equivalent to the Calabazar* Formation. It has been recognized only in the Colorados field, where it reaches 2600 ft (800 m). It should be emphasized that the Coniacian and Santonian have not been recognized in northern Cuba. Campanian –Maastrichtian: —The Campanian– Maastrichtian interval consists of up to 1550 ft (470 m) of calcarenites, calcirudites, coarse limestones breccias, calcareous shales, and cherts. The fauna consists of Asatomphalus mayaroensis, Vaughanina cubensis, Globotruncana spp., and orbitoides. It suggests the Lutgarda* Formation and is also similar and coeval to the Amaro* and Cacarajı´cara formations. It is unconformably under the middle–upper Paleocene.

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FIGURE 76. North-central terrane, northern Cuba, correlation chart.

Middle – Upper Paleocene: — The middle – upper Paleocene interval is described as up to 650 ft (200 m) of micritic limestones, calcarenites, marls, shales, and igneous-derived sandstones. The fauna contains Globorotalia velascoensis. This unit is similar and equivalent to the Vega* Formation and the Pica Pica Member of the Manacas Formation. Lower Eocene: — The lower Eocene interval is described as up to 1300 ft (400 m) of an olistostrome complex containing blocks of the underlying limestones, gabbros, serpentine, etc. It contains Globorotalia palmerae, Globorotalia formosa, and Globorotalia rex. It is similar to and correlates with the Rosas* Formation and the Vieja Member of the Manacas Formation.

Las Villas* Belt Discussion The Las Villas* belt shows the most complete sedimentary section in central Cuba. It exposes 3875 ft (1180 m) of Upper Jurassic dominantly shallow-water carbonates, with influx of deeper and/or open-water elements. Conformably over these, the Cretaceous is represented by ±2100 ft (640 m) of lithified nannoplankton and radiolarian oozes interbedded with carbonate bank-derived turbidites. The Neocomian nan-

noplankton limestones are the northern equivalent of southern-derived conglomerates containing Upper Jurassic limestone fragments. The Coniacian and Paleocene have not been recognized. The lower–middle Eocene is represented by at least 3620 ft (1100 m) of detrital sediments, ranging from pure carbonate breccias at the base, shales in the middle, and igneousderived, noncalcareous sandstones and conglomerates at the top. These conglomerates become orogenic megabreccias near the thrusts. It should be noted that no igneous-derived detritus is present in this belt until the lower–middle Eocene, above the Sagua* conglomerate. The rate of sedimentation for the Upper Jurassic is ±260 ft/Ma (80 m/Ma), and its thickness is on the same order of magnitude as in the Yaguajay* belt. However, the rate of sedimentation drops to ±29 ft/Ma (±8.8 m/Ma) for the Cretaceous. This is quite typical of deep-water conditions. For instance, in the Deep Sea Drilling Project Hole-535, drilled in 11,316 ft (3450 m) of water, 1738 ft (530 m) of marly limestones with approximately 35% porosity were deposited in 43 Ma. Correcting for the difference in compaction, one obtains a sedimentation rate of 28 ft/ Ma (8.5 m/Ma).

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FIGURE 77. Stratigraphic section: Las Villas* belt, northern Cuba, subsurface.

The flanks of the Quemado de Gu ¨ ines and Guayabo anticlinoria show a marked stratigraphic asymmetry (Capitolio*-Sabanilla* formations). In view of the fact that (1) their width is on the order of 8 km (5 mi), (2) the dips are in the order of 508, and (3) numerous longitudinal reverse faults exist (dipping both north and south), the original predeformation distance between the two flanks could easily have been between 20 and 30 km (12 and 18 mi). This provides a measure of the rate of the horizon-

tal facies changes that occurred across the Las Villas* belt. In addition, the Yabu window, surrounded by the Cifuentes* belt, is 7.5 km (4.6 mi) southwest of the Guayabo anticlinorium, and the Fidencia anticline is 5 km (3 mi) southwest of the Las Villas* belt and separated from it by the basic igneous-volcanic province. Therefore, the minimum observable width of the belt could have been on the order of 50 km (31 mi). The total displacement of the Las Villas* fault is impossible to estimate.

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FIGURE 78. Central Cuba, Placetas* belt.

Placetas* Belt It has an irregular outline, but in general, has a northwest–southeast trend. It extends from Calabazar de Sagua, through Vega Alta, central Fidencia, north and east of Placetas, disappearing some 16 km (10 mi) to the southeast of Placetas. It reappears again some 10 km (6 mi) farther on to form the core of a 26-km (16-mi)-long canoe-shaped body, the Jarahueca Fenster, with the Jarahueca oil field in its center, south of the town of Jarahueca (see Figure 78). The Placetas* belt was named by Pardo in 1954, and it is part of (1) Hatten et al.’s (1958) Las Villas unit, (2) Ducloz and Vaugnat’s (1962) Placetas zone, (3) Meyerhoff and Hatten’s (1968) Placetas zone, (4) Khudoley and Meyerhoff’s (1971) Las Villas zone, (5) Shopov’s (1982) Cifuentes and Rancho Veloz subzones of the Placetas zone, (6) Dilla and Garcı´a’s (1985) Placetas subzone of the Las Villas zone, (7) Knipper and Cabrera’s (1974) Placetas(?) zone, and (8) Hatten et al.’s (1988) Las Villas unit. In Pushcharovsky et al. (1988), it is part of the Placetas zone. Again, as in the case of the Las Villas* belt, the boundaries of all these belts, zones, and units do not necessarily correspond to each other. The succession can be divided as follows (see Figure 79).

Ronda* Formation This unit has been mapped both in the Placetas* and Cifuentes* belts. It is estimated to be ±1000–

2000 ft (±300 – 600 m) thick, but this figure could be off because of the intense faulting and isoclinal folding commonly present. It consists of thin, platy, bedded limestone and interbedded, thin, yellow and brown calcareous shales. Hatten et al. (1958) describe a Placetas Formation that probably includes the Ronda, but seems to also include several other lithologic units. It is assigned a Neocomian to Cenomanian age. The Ronda Formation is very probably synonymous with the Veloz Formation of many authors, including Hatten et al. (1958) and Pushcharovsky et al. (1988). Some authors (Dilla and Garcı´a, 1985, for example) restrict it to the Berriasian–Valanginian, whereas Pushcharovsky et al. (1988) and others consider it Upper Jurassic through Aptian. Three distinct types of limestones, each with a significant areal distribution, have been recognized. They appear to grade into each other and are as follows: type 1: consists of brown limestone, with slightly wavy laminations of argillaceous, carbonaceous material (somewhat like, but not as pronounced as, in the Capitolio* Formation limestones). type 2: the wavy laminations are absent, and the limestones are uniformly brown. type 3: the limestones are very dark brown to jet black, lack laminations, and have a somewhat coarser crystalline aspect.

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FIGURE 79. Stratigraphic section, Placetas* belt.

Most of the limestones are biomicrites consisting almost entirely of Nannoconus spp. Nannoconus steinmanni is dominant, radiolaria are abundant, and ostracods and ammonite remains are present. Calpionella spp. has been found in the Ronda lithology interbedded with the Jobosi* Formation of the Cifuentes* belt. The age is considered Neocomian and Aptian. The Placetas* belt is characterized by types 1 and 2. In the Placetas* belt, the base of the formation has never been observed, but in the Cifuentes* belt, it grades into and is in part equivalent to the underlying Jobosi* Formation. It is conformable with the overlying

Constancia* Formation. This unit is considered to be correlative with the Capitolio* and Sabanilla* formations of the Las Villas* belt.

Constancia* Formation The Constancia* Formation consists of ±50 ft (±15 m) of brown, sandy, micaceous limestone and limy micaceous quartz sandstone interbedded with yellowtan shales. The sandstones contain abundant mica, some quartz, iron oxide–stained limestone grains, and angular limestone fragments up to 1 cm (0.4 in.) in diameter. These sandstones derive the bulk of their components from metamorphic rocks, as indicated

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by the abundance of muscovite and the presence of tremolite, metamorphic quartz, hornblende, zircon, blue tourmaline, garnet, etc. Although uncommon and badly weathered, some volcanic, mostly basaltic, grains exist. The name Constancia Formation is widely used in the present literature to describe a sandy, arkosic limestone unit underlying the Veloz Formation. It appears to be synonymous with the Jobosi* and has been attributed a Tithonian – Berriassian age. This is the way it is shown in Pushcharovsky et al. (1988). See the comments on the Jobosi-Constancia nomenclature problem under the Jobosi* Formation description for more details. As will be seen below, the source of the abundant metamorphic components, especially muscovite, is puzzling because in the Aptian, the metamorphism of the Escambray massif to the south had not occurred yet, and the known exposed allochthonous preCretaceous basement does not contain muscovite. The fauna consists of Globigerina cretacea sl., Globigerinella sp., Pithonella spp., common radiolaria, and fragments of Orbitolina sp. The Constancia Formation is considered Aptian in age. This unit grades into and is equivalent to the upper part of the older Ronda* Formation. It is partly conformably and partly unconformably overlain by the Carmita* Formation.

Carmita* Formation This unit is probably included in Hatten et al.’s (1958) Placetas Formation, and it is recognized by Dilla and Garcı´a (1985). Unfortunately, because these authors lump the Placetas* and Cifuentes* belts together, they show the Carmita overlying the Santa Teresa Formation instead of being its calcareous equivalent. The thickness of this unit is unknown, but probably is on the order of several hundred feet. It consists of a tan calcilutite to dense slightly argillaceous limestone with abundant secondary nodular black and brown chert. Intervals of thin, flat-bedded primary chert and brown to gray, carbonaceous, and noncalcareous shales with occasional tan dense, nodular limestone stringers exist. The limestones are commonly lightly banded, stained with limonite, and have small, clear, calcite-filled foraminifera and radiolaria arranged in rows parallel to the bedding. At the base of the formation are two recognizable lithologic units, which are described below. Encrucijada* member. — The Encrucijada* member consists of a white, spotted calcarenite with much

clear calcite cement and abundant, angular, creamwhite limestone components, interbedded with brown, nonfissile, thin-bedded shale and reddish brown to brownish gray argillaceous limestone. Bermejal* member.— The Bermejal* member consists of a distinctive limestone conglomerate with conspicuous white and tan angular fragments in a darkbrown carbonaceous limestone matrix. These members were at one time called formations related to the Carmita*. Because of the deformation, the relations between them and the Carmita* Formation are not clear, but they are probably transitional into one another. The fauna of the Carmita* Formation is mostly pelagic and consists of abundant radiolaria, Globigerina cretacea sl., Rotalipora appenninica, Globigerinella sp., Pithonella spp., Schakoina cenomana bicornis, and rare Guembelina sp. Some Nannoconus spp. are present in situ at the base of the formation and are also reworked throughout. The age is therefore considered to extend from the Albian through the Turonian. Some shark remains have been reported and described (Mutter et al., 2005). This formation is equivalent to the Calabazar* and Mata* formations of the Las Villas* belt. The nature of the contact with the overlying Corona* Formation is not clear, but there appears to be a hiatus or a slight unconformity. The Carmita* Formation represents an influx of fine, noncalcareous clastic material and is a transition between beds of equivalent age in the Las Villas* and Cifuentes* belts.

Corona* Formation Other authors do not seem to recognize this unit. In Pushcharovsky et al. (1988), it is probably included in the Amaro Formation of the Placetas zone and assigned a Maastrichtian age. This unit consists of an estimated ±200 ft (±60 m) of an interbedding of 1) gray, medium calcarenite with common green and occasional red and black igneous grains 2) green to yellow-brown calcareous medium to fine sandstones, some with abundant quartz, some with mostly colored volcanic grains 3) pastel green and pink clay shales, sticky in fresh outcrops 4) maroon and brown, thin-bedded primary cherts, some looking like the silicification of the shales 5) argillaceous, very fine, fragmental, soft, maroon limestone

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FIGURE 80. Central Cuba, Cifuentes* belt.

6) pink to light-maroon argillaceous, semiporcelaneous, dense limestone All the above lithologies occur in thin to medium beds, although the calcarenites occur in thick beds or as thick packages of medium beds. The Corona* Formation is unconformably overlain by young Tertiary. Based on its faunal content, it is assigned a Santonian through Maastrichtian age. The Corona* Formation is the southern equivalent of the Lutgarda* and the northern equivalent of the Miguel* Formation. Note that this is the northernmost Upper Cretaceous unit to contain igneous-derived detritus.

Placetas* Belt Discussion The Placetas* belt does not expose rocks older than the lowermost Cretaceous. The reason for this is unknown, but based on the presence of southern-derived conglomerates with Jurassic components in the Las Villas* belt, it is reasonable to assume that the Jurassic was eroded prior to the deposition of the Neocomian. The presence of metamorphic-derived material during the Aptian indicates the erosion of an unknown metamorphic basement. Except for the presence of silicate clastics, the Cretaceous section is very similar to that of the Las Villas* belt, and although thicknesses cannot be accurately measured, they are believed to be on the same order of magnitude as in the Las Villas* belt. In contrast with the Las Villas* belt, there was, in

the Maastrichtian, an influx of igneous detrital material derived from the early orogenic activity to the south. The upper Cenomanian through Coniacian is missing.

Cifuentes* Belt The Cifuentes* belt was named by Pardo in 1954, and it is part of (1) Hatten et al.’s (1958) Las Villas unit, (2) Ducloz and Vaugnat’s (1962) Placetas zone, (3) Meyerhoff and Hatten’s (1968) Placetas zone, (4) Khudoley and Meyerhoff’s (1971) Las Villas zone, (5) Shopov’s (1982) Cifuentes and Rancho Veloz subzones of the Placetas zone, (6) Dilla and Garcı´a’s (1985) Placetas subzone of the Las Villas zone, (7) Knipper and Cabrera’s (1974) Placetas(?) zone, and (8) Hatten et al.’s (1988) Las Villas unit. In Pushcharovsky et al. (1988), it is part of the Placetas zone. Again, as in the case of the Las Villas* belt, the boundaries of all these belts, zones, and units do not necessarily correspond to each other. The Cifuentes* belt outcrops most extensively in Las Villas province; in central Camaguey, the exposures are very limited (see Figure 80).

Las Villas Province Area The bulk of this belt in Las Villas province can be circumscribed by a line running from Coralillo to Rancho Veloz to the southeast, through southwest of Sitiecito, Cifuentes, and swinging back at Loma Bonachea to the northwest, toward Santo Domingo,

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FIGURE 81. Stratigraphic section: Cifuentes* belt, upper (southern) plate. where it disappears under a Neogene cover to reappear southeast of the Motembo oil field. The Cifuentes* belt also can be seen associated with the Placetas* belt, specially rimming the Placetas* belt body in the vicinity of Jarahueca oil field. In the type Cifuentes* belt, near the town of Cifuentes, a stack of three thrust plates has been mapped. The stack is interpreted as a north to south succession of facies, the upper plate being southernmost. Along the strike of the Cifuentes* belt, the number of plates outcropping varies; although all three are present to the northwest, only the upper one is recognizable to the southeast. The units composing

this belt will be described from lower to upper plate. Figure 81 is a composite of the three plates, but is more representative of the upper (southern) plate.

Lower (Northern) Plate Ronda* Formation.— Here, the Ronda* Formation is identical with the brown, with slightly wavy laminations, type 1 described under Placetas* belt. The base is in fault contact with a sliver of basic igneous-volcanic province. It grades upward into the Constancia* Formation. Constancia* Formation.— This unit has the same development as in the Placetas* belt. It grades up into the Encrucijada* Member of the Carmita* Formation.

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Carmita* Formation. — Encrucijada* Member.—It is similar to that described under the Placetas* belt, and it grades laterally into the Santa Teresa* Formation. Santa Teresa* Formation. — Although this unit is considered to be ±500 ft (±150 m) thick, this figure is only an order of magnitude because of the intense folding and faulting. This unit consists of a monotonous succession of thin, 1–2-in. (3–6-cm) flat-bedded red, brown, yellow, gray, and black primary chert interbedded with dark fissile, carbonaceous but sometimes marly or clayey shales of probable volcanic origin. It is mineralized and stained with manganese oxides. This is characteristically a noncarbonate unit. It is a deepwater deposit and received a strong influx of silica and fine detritus from contemporaneous submarine volcanism in the Cabaiguan* sequence to the south. A marked unconformity exists between it and the overlying Amaro* Formation. Hatten et al. (1958) included this unit in the Placetas Formation. The name Santa Teresa appears in much of the present literature. Dilla and Garcı´a (1985) consider it Aptian – Albian. In Pushcharovsky et al. (1988), it is described as above and shown as ranging from the Albian through the Cenomanian. This unit is very poorly fossiliferous, containing only unidentifiable radiolaria and other remains. Because of its stratigraphic relationships, it has been considered to range from upper Aptian through Turonian in age. As already mentioned, it grades laterally into the Carmita* Formation, but it could be equivalent only to the lower part. This is supported by the fact that in some areas, the Carmita* lithology overlies the Santa Teresa*. A marked similarity also exists between the Santa Teresa* and the Huevero* Formation of the volcanic Cabaiguan* sequence to the south. The Huevero* lies immediately under the Cenomanian Gomez* Formation. As will be seen below, the Cenomanian was a time of essentially no volcanic activity in central Cuba and separates an older basic submarine volcanism from younger, more acid, arc volcanics. If the Santa Teresa* Formation is related to volcanism, it should not be of Cenomanian age, but either younger or older. In view of its relationship with the underlying Constancia* and Ronda* formations, and that its lithology suggests an association with submarine instead of arc volcanism, an upper Aptian through Albian age, not younger than lower Cenomanian, is more likely. The Santa Teresa* Formation is very widespread in Cuba, and its lithology has been recognized from

the Pinar del Rio to central Camaguey province (a similar lithology has been reported in Hispaniola). Amaro* Formation.—It consists of ±200 ft (±60 m) of gray, medium heterogeneous limestone with brightgreen igneous grains and small, green clay pellets interbedded with light-gray to white or pink, very dense, porcelaneous, pure limestone with a characteristic network of tiny calcite-filled cracks. It is thickly bedded and, when standing vertically, weathers to a flat but sharply fluted surface that is a distinguishing mark of the formation. The basal part of the formation is a coarse conglomerate made up principally of fragments of chert from the underlying Santa Teresa* Formation and heterogeneous calcarenites containing Jurassic Jaguita* oolites, mollusks (rudists), and other carbonate fragments and igneous grains. In the northern part of the Cifuentes* belt are interbeds of green clay shale. The Amaro* Formation contains a bed, up to 50 ft (15 m) thick, of white, tan, or pink dense limestone, commonly with secondary chert, and characterized by abundant, very small specimens of Guembelina sp. and Globigerina cretacea sl. This bed was formerly referred to as the Macagua* Formation. The name Amaro is widely used in the literature and must be derived from the original Gulf name. Presently, it includes the Rodrigo* Formation and, very likely, the Corona* Formation. In Loma Camajan, central Camaguey, the Camajan Formation is synonymous with Amaro. The Amaro Formation is shown in Pushcharovsky et al. (1988) as 165–1650 ft (50–500 m) of breccias, conglomerates, limestones with components of chert, igneous rocks, and clay of Maastrichtian age in the Zulueta zone. As already mentioned, Pszczo´lkowski (1986b) considers the Amaro* Formation (Amaro* and Rodrigo* formations) a megabed, with a volume of 240 km3 (57 mi3), correlative with the Cascarajı´cara of Pinar Del Rio. He considers them to represent one major turbidite event caused by one large earthquake possibly related to the Chicxulub meteorite impact at the K-T boundary. There is no question about the turbiditic origin, but the correlation with the Lutgarda* Formation, consisting of a large number of turbidite flows interbedded with pelagic sediments ranging from the Santonian through the Maastrichtian, does not support that it was a single depositional event. Perhaps the meteorite triggered a larger flow in an area that was turbidite prone. The Amaro* Formation contains a rich, larger foraminifera fauna, with Sulcoperculina sp., Sulcorbitoides sp., Vaughanina sp., Orbitoides sp., Pseudorbitoides sp., Lepidorbitoides sp., and Dicyclina sp. In addition, abundant Globotruncana lapparenti sl., Globotruncana stuarti,

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FIGURE 82. Central Cuba, Cifuentes* belt basement outcrops.

Globotruncana ganseri, Guembelina spp., Globigerina cretacea sl., and Pithonella spp. are present. This assemblage indicates a Santonian through Maastrichtian age. The mixture of shallow-water and pelagic forms suggest turbidites in open, relatively deep waters. It grades into the overlying Rodrigo* Formation. This unit is correlative with the Corona* and Lutgarta* formations to the north. All three are similar in the sense that they are dominantly detrital biogenic limestones, with closely related faunas, and that most of the components are derived from shallow carbonate banks and deposited in relatively deep waters. However, distinct differences exist, such as textural and bedding characteristics and an increasing influx of igneous-derived material from the south. Rodrigo* Formation. — It consists of ±200 ft (±60 m) of gray to maroon dense, fine, fragmental argillaceous soft limestone with green clay and black carbonaceous inclusions. It is not recognized in the literature. The Rodrigo* Formation contains abundant pelagic foraminifera, among them Globotruncana lapparenti sl., Globotruncana stuarti, Globotruncanella havanensis, Globotruncanella contusa, Globotruncanella ganseri, Globigerina cretacea sl., Rugoglobigerina macrocephala, Globigerinella sp., and Guembelina spp. It also contain Pithonella spp. and Robulus spp. This fauna indicates a late Maastrichtian age. The upper Eocene overlies this unit with marked unconformity.

Middle (Central) Plate. — This plate is identical with the lower (northern) one, except that the Lower Cretaceous Ronda Formation has lost all similarities with the Capitolio* Formation. Here, it consists of typical type 2 brown radiolaria and rock-forming Nannoconus limestones separated by yellow clay intervals. Upper (Southern) Plate. — This plate is characterized by exposing the only known basement of the calcareous sedimentary section (see Figure 82). Basement. —In Las Villas province, one locality exists where the contact between the Cifuentes* belt sediments and basement has been unquestionably observed, near the La Rana village in western Las Villas province. Two other localities show a very probable basement under the sediments, but the contact is tectonically disturbed. These are Sierra Morena and Tre´s Guanos in western and in eastern Las Villas province, respectively. La Rana locality. — About 13 km (8 mi) southsouthwest of the town of Jarahueca is a large outcrop of granodiorite surrounded by Upper Cretaceous volcanics and possibly below a Paleocene conglomerate (Taguasco* Formation) of the volcanic Cabaiguan* sequence. The granodiorite is medium grained and cataclastic and appears similar to several other diorite-granite type of rocks that outcrop in the northern Las Villas province. Patches of serpentine also exist. Over the granodiorite is a granodiorite regolith that grades

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upward into the Jobosi* Formation, the basal conglomerate below the Ronda* Formation. It is a normal sedimentary contact. In view of the presence of Neocomian Calpionella spp. and Nannoconus spp. in the basal Jobosi* Formation, the granodiorite must be pre-Neocomian, possibly Jurassic. The section is nearly horizontal and is allochthonous. It appears to be a large olistolith (or slide block) that perhaps moved during the Paleocene. The presence of this exposure has never been reported in the literature. In Pushcharovsky et al. (1988), an outcrop designated ‘‘Upper Cretaceous granodiorite, etc.’’ is shown at this location but with no indication of overlying Veloz Formation. Tre´s Guanos locality. — At the southeastern end of the Jarahueca area of Placetas* belt exposures are some outcrops of a granodiorite (quartz monzonite) of the same family as the granodiorite at La Rana. Hatten et al. (1958) observed the Quemadito ( Jobosi*) Formation in normal sedimentary contact over the quartz monzonite. Although the relationship is structurally more complex than at La Rana, the Jobosi* Formation is unquestionably present, which is further evidence for a pre-Neocomian age basement. Unfortunately, an age determination of this rock based on the K-Ar method run by Lamont Geological Laboratory on biotite yielded an age of 61 ± 3 Ma. Somin and Milla´n (1981) report a K-Ar determination of 79 ± 5 Ma. This might represent an Upper Cretaceous or early Tertiary overprint and not the true age of the rock. Sierra Morena locality. — About 10 km (8 mi) southsouthwest of the town of Sierra Morena (Socorro, Can ˜as River, Coralillo) is a cataclastic pegmatitic granite associated with marble and patches of serpentine, Jobosi* and type 3 Ronda* formations. The outcrops cover an area of some 12  3 km (7.5  1.8 mi). These units appear to lie in a complex structure surrounded by the Upper Cretaceous of the Cifuentes* belt. Pszczo´lkowski (1983, 1986b) mapped the area in some detail. He interprets the granite as a window through the Cifuentes* belt. The granite and associated outcrops coincide with the strongest Bouguer gravity low of the island (Gulf’s gravity survey), which lends strong support to their being allochthonous and not deep rooted. This basement has been named the Socorro complex (Renne et al., 1989a, b; Iturralde-Vinent, 1996). The analyses of four samples of the granite (Somin and Milla´n, 1981; Renne et al., 1989a, b), dated by whole rock K-Ar method, yielded 142 ± 3, 150 ± 5, 139 ± 6, and 140 ± 2 m.y. The U-Pb method gave the intrusion age of zircons at 172.4 m.y. and the K-Ar age deter-

mination on the marble phlogopite gave the intrusion age at 910 ± 25 and 945 ± 20 m.y. The original limestone is therefore older, suggesting a Precambrian basement affected by a Kimmeridgian–Tithonian magmatic intrusion. Jobosi* Formation.—The Jobosi* Formation consists of ±50 ft (±15 m) of quartz granule to pebble-size conglomerates, sandstones, and siltstones containing abundant fragments of type 3 Ronda* Formation. In addition to Ronda*, the conglomerates have components of quartz and granodiorite, as well as grains of serpentine, sericite schist, and porphyry. The sandstones and conglomerates are interbedded with and grade up into the type 3 black Ronda* Formation limestones. At La Rana, where the lower contact is the best exposed, it grades down into a granodiorite regolith. Hatten et al. (1958) named the Quemadito Formation in Tre´s Guanos, which, by the description, is obviously synonymous to Jobosi*. It should be noted that these authors assign it to the Upper Jurassic, although it has the same type locality and fauna as Jobosi*. My personal opinion is that where it was observed, it is of Neocomian age, but it could very well extend into the Upper Jurassic at other localities. This difference in age assignment and the fact that in some early Gulf reports there was a question whether the Constancia* Formation was the Jobosi* lateral equivalent, have created some confusion in the literature. Some authors have used the name Constancia as a synonym to Jobosi*; Kantchev et al., (1976) and Pushcharovsky et al. (1988) show this unit as the Tithonian– Berriassian Constancia Formation of the Placetas zone, consisting of polymict and arkosic sandstones and sandy limestones underlying the Veloz Formation. Other authors, including Dilla and Garcı´a (1985), used the names Quemadito (Jobosi*) and Constancia as two different units in their original sense. The interbedded type 3 Ronda Formation contains Calpionella spp., radiolaria, and Nannoconus spp., including Nannoconus steinmanni, which are rock forming. The age of the upper part of the formation is considered Berriassian, whereas Tithonian ammonites have been found within the formation (Shopov, 1982). Foraminifera (Globuligerina sp.) of questionable Oxfordian age have been reported (Pszczo´lkowski and Myczynski, 2003). In addition to La Rana, this unit is found in Tre´s Guanos and Rancho Veloz. The Jobosi* Formation must have formed under unique conditions. The granodiorite regolith, with its altered feldspars, indicates weathering of the granodiorite. However, the interbedding with the

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type 3 Ronda* Formation, consisting mostly of nannoplankton, and the nannoplankton in the matrix of the conglomerates indicate deposition in deep, anoxic water. In addition, the presence of black Ronda* fragments, showing no sign of prediagenetic deformation or weathering, suggests that an appreciable thickness of Ronda* was already deposited and at least partially consolidated before its erosion and redeposition, together with granodiorite fragments, in a deepwater environment. This strongly suggests deposition at the base of a very active fault scarp such as in the Upper Jurassic–Lower Cretaceous rifts of west Africa (Lucula-Bucomazi of Cabinda). Similarly, the lack of Jurassic carbonate components in the conglomerates suggests that the Ronda* Formation was deposited on a granodiorite basement after previous erosion of the limestones, or that Jurassic carbonates were never deposited in the area. If the Oxfordian age was confirmed, the latter case would be likely. Ronda* Formation. — In the southern plate, this formation contains only the dark-gray to black type 3 limestones. Good evidence of the pre-Santonian unconformity exists because the Ronda Formation can be overlain by the Maastrichtian Amaro* Formation or separated from it by a much reduced section of Santa Teresa* Formation. Vega Alta Formation.—Pushcharovsky et al. (1988) show a Vega Alta Formation in the Placetas zone that consists of 820–980 ft (250–300 m) of a chaotic complex containing blocks of limestones, serpentinite, and volcanics in a sandy and argillaceous matrix of Paleocene–Eocene age. Although this description suggests the Upper Vega* Formation (Rosas*), Gulf never found any Eocene sediments associated with the belts thought to be equivalent to the Placetas zone (Placetas* and Cifuentes* belts). The absence of Eocene sediments in these belts was considered one of their important features. This was odd because the Vega* Formation was recognized over the Cabaiguan* sequence. From its distribution on the map, the Vega Alta Formation appears to be what Gulf mapped as a complex tectonic mixture (folded and faulted imbrications, olistostromes) of components from the Cifuentes*, Placetas*, Domingo*, and Cabaiguan* sequences, and in places, a Maastrichtian brown shale called the Miguel* Formation (see Domingo* sequence) that appears to underlie the Domingo* sequence. These complexly deformed areas include rubble zones and calcite mesh (ophicalcites). Although the deformation that brought about this tectonic mixture is certainly of lower–middle Eocene age, in the true sense, it was not considered a sedimentary deposit.

Central Camaguey Area In the central Camaguey area, the lithologies of the Cifuentes* belt can be found southwest of the Sierra de Cubitas in small areas surrounded by serpentine. They also outcrop in the southern half of the Sierra de Camajan. They are shown as part of the Esmeralda complex in Pushcharovsky et al. (1988). Sierra de Camajan Locality. —At the Nueva Maria quarry, Iturralde-Vinent and Morales (1988) describes a sedimentary contact between the strongly folded Veloz (±Ronda*) Formation and an underlying sequence of tholeitic basalts (see Figures 82, 83). Nueva Maria Formation. — This unit consists of more than 203 ft (62 m) of interbedded black and gray amygdular pillow basalts, black and gray cataclastic obsidian, and dark-gray laminated tuffs. The chemical composition of the basalts is similar to that of oceanic tholeites. The tuffs contain radiolaria, calpionellids, and molds of small ammonites of a middle Tithonian age. These basalts yielded a K-Ar age of 146 ± 6 Ma. Veloz (Ronda*) Formation. — The Veloz Formation is essentially synonymous with the Ronda* Formation. In this locality, the basal part of the Veloz Formation is conformable over the Nueva Maria Formation and contains thin tuffs and glassy laminae interbedded with the fine-grained limestone biomicrites. The Veloz contains the same middle Tithonian fauna as the Nueva Maria Formation. The entire sequence is allochthonous. This locality is the only one in central Cuba where a carbonate belt is seen in normal stratigraphic contact with the basic igneous-volcanic province, with the type 3 dark-gray to black Ronda overlying the Nueva Maria Formation. As will be seen later, pillow basalts are commonly associated with the deep-water carbonates of the northern Rosario belt in the southwestern terrane of Pinar del Rio. This unit, in turn, is overlain by the Santa Teresa, Carmita, and, separated by a Coniacian – Campanian hiatus, the Amaro formations. Only the Veloz and the Carmita formations are shown in Pushcharovsky et al. (1988).

Northern Cuba Area According to Kuznetsov et al. (1985), the rocks assigned to this belt can be subdivided into two superimposed allochthonous miogeosynclinal thrust plates (not necessarily correlative with those observed in Las Villas area) (see Figures 75, 84). Lower Plate.— The lower plate is recognized in Cantel and Camarioca fields.

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FIGURE 83. Stratigraphic section: Cifuentes* belt, Loma Camajan.

Aptian–Albian.—The Aptian–Albian unit consists of up to an apparent 2755 ft (840 m) of limestones, sometimes dolomitized, and cherts with shales, possibly corresponding to the Ronda* and Santa Teresa* formations. The fauna contains Nannoconus sp., Ticinella sp., Schackoina sp., Hedbergella sp., Pithonella sp., and Globigerinelloides sp. The thickness is certainly structurally exaggerated. Campanian – Maastrichtian. — The Campanian – Maastrichtian unit consists of between 150 and 650 ft (50 and 200 m) of siltstones, sandstones, and calcarenites containing Globotruncana spp., Sulcoperculina sp., Vaughanina sp., and Pseudorbitoides sp. This

unit suggests the Corona* and Rodrigo* formations of the Placetas* and Cifuentes* belts, although it appears to contain a higher percentage of silicate clastics. Upper Plate. — The upper plate is recognized in Varadero, Camarioca, and Guasimas fields. Aptian – Albian. — The Aptian – Albian unit consists of rocks identical with those of the lower plate: up to an apparent 2000 ft (600 m) of limestones, sometimes dolomitized, and cherts with shales, possibly corresponding to the Ronda* and Santa Teresa* formations. The fauna contains Nannoconus sp., Ticinella sp., Hedbergella sp., and Globigerinelloides sp.

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FIGURE 84. Stratigraphic section: Cifuentes* belt (upper and lower plates), northern Cuba, subsurface.

Cenomanian –Turonian. — The rocks representing this interval of time have not been recognized in the lower plate and consist of up to 1650 ft (500 m) of polymict sandstones and siltstones interbedded with limestones containing Globotruncana sp., Rotalipora sp., Schackoina sp., and Hedbergella sp. This section containing abundant coarse clastics has been recognized in a few wells and appears to be in part equivalent to the Santa Teresa* or Carmita* formations, but (barring structural complications) has greater af-

finity with rocks of the same age in the La Esperanza belt of western Cuba and not the Cifuentes* belt. Campanian – Maastrichtian. — The Campanian – Maastrichtian unit consists of up to 2600 ft (800 m) of arkosic sandstones and gravels, occasionally with anhydrite(!), containing Pseudorbitoides sp. It is unfortunate that no better description of this unit is available; the anhydrite could be related to that of the San Adrian diapirs, and if the arkosic sandstones and gravels are in place in the Cifuentes* belt, it could indicate

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a Late Cretaceous erosion of nearby allochthonous granodiorite highs such as the Sierra Morena of central Cuba. Upper Paleocene – Middle Eocene. — The Upper Paleocene–Middle Eocene unit consists of up to 1650 ft (500 m) of shales, siltstones, sandstones, and conglomerates, as well as an olistostrome-containing gabbro and serpentine. This section is reported to contain Globotruncana spp., Sulcoperculina sp., and Vaughanina sp., which is the reason for the assignment to the Campanian–Maastrichtian by Kuznetsov et al. (1985). In my opinion, this section is very suggestive of the younger Vega* and Rosas* formations or the Pica Pica and Vieja Members of the Manacas Formation of upper Paleocene–middle Eocene age (see the following Cifuentes* belt discussion). This same section has been found toward the east in Guasimas, Cardenas, and Camarioca.

Cifuentes* Belt Discussion This belt represents the southernmost part of the miogeosyncline, with minor influences from volcanism (clay and cherts), and the deepest and most anoxic depositional conditions. This is the only belt where basement, although allochthonous, is exposed. This belt was the farthest away from the North American margin and was deposited on granodiorite and tholeites; it is therefore considered the most oceanic of the carbonate belts. As in the Placetas* belt, the thicknesses cannot be measured, and the Tithonian dolomites and oolitic limestones are absent; however, the base of the pelagic carbonates has been considered uppermost Jurassic in places. The Cretaceous sediments that compose this belt are the most extensive in Cuba, having been recognized from the Pinar del Rio to central Camaguey. This belt is also characterized by having most of the Turonian–Santonian missing, although no evidence of a subaerial unconformity exists. Although the area where this belt was deposited was originally the most remote from the carbonate banks, it nevertheless received from them a considerable amount of turbiditic material during the Maastrichtian. In the northern Las Villas province, outcrops of similar diorite-granite igneous rocks have been included in the igneous Domingo* sequence. These show cataclastic alteration. In the field and under the microscope, they are practically indistinguishable from the Manicaragua and southern Camaguey province intrusive bodies that, from field relationships and K-Ar, have been dated as ±85 m.y. of age or Coniacian–Santonian. Presently, no report exists on the ages of most of these bodies. They could be late

intrusions associated with the Cretaceous volcanism or an older Jurassic basement mechanically incorporated in the ultrabasics through tectonism. However, the presence of granodiorite and marbles of possible Precambrian age (±925 m.y.) affected by an Upper Jurassic (±145 m.y.) thermal event and the tholeitic basalts of Upper Jurassic age underlying the Ronda* (Veloz) Formation in normal sedimentary contact suggests that the Precambrian basement of the North American continental margin was fragmented and invaded by oceanic rift basalts during the Middle and Upper Jurassic. Other evidences of Late Jurassic – Early Cretaceous rifting exist, such as the presence of the Sabanilla* and the Jobosi* formations with southern local sources of detritus. An important difference of opinion exists between Hatten et al. (1958, 1988), Meyerhoff and Hatten (1968), and Meyerhoff (in Khudoley and Meyerhoff, 1971), on the one hand, and myself, on the other, on the present position of these basement outcrops. Although I agree that they could represent remnants of a ridge that might have separated the miogeosyncline from the eugeosyncline, I interpret them as the most allochthonous elements of the sedimentary basin, the basement of the highest sedimentary plate below the ophiolite obduction. However, these authors consider them as the relatively autochthonous (nothing is totally autochthonous in Cuba) basement of Meyerhoff’s ‘‘median welt.’’ Drilling. —Several wells have been drilled in the Las Villas*, Placetas*, and Cifuentes* belts. Gulf Hicacos-1. — This was drilled in northeastern Cardenas Bay in 1949 by Cuban Gulf (Gulf Oil). It penetrated the Las Villas* belt at 2290 ft (698 m) to the total depth at 5045 ft (1538 m) below an Eocene to Holocene cover and was cut by a major fault at 4030 ft (1229 m), bringing the lower–middle Eocene (Sagua* or Vega*) under the Upper Jurassic Caguaguas* Formation. Texaco Guayabo-1. — This was drilled by Texaco in the Guayabo anticlinorium, 2.5 km (1.5 mi) southwest of the Las Villas fault. One of the main objectives was to drill through the fault into the underlying Yaguajay* belt; this objective was not reached, indicating that the fault is steeper than 508. The following section was drilled: 0– 103 ft (0 –31 m): alluvium. 103 –183 ft (31 – 56 m): Caguaguas* Formation. 183 –2910 ft (56 – 887 m): Jaguita* Formation. 2910 ft (887 m): Reverse fault.

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2910–3060 ft (887–933 m) Calabazar* Formation. 3060–3292 ft (933–1004 m): Ramblazo* Formation. 3292 – 5760 ft (1004 – 1756 m): Capitolio* Formation. 5760 – 5940 ft (1756 – 1811 m): Caguaguas* Formation. 5940 to total depth at 10,010 ft (1811 to total depth at 3052 m): Jaguita* Formation. The Hoyo Colorado* Formation was not reported, but it is believed to be present under the Jaguita*. The moderate to high dips average 508 to the southwest. The Jurassic has porosities of up to 10%. Tar (18-58 API) shows were present throughout the section, mostly in fractures, and 6 gal of tar were collected in a test between 7488 and 7700 ft (2283–2348 m). Boca de Jaruco – Via Blanca: — These fields are along the north coast between Habana and Matanzas. The following section is interpreted from scout information provided by Petroconsultants (1990, personal communication). 0 ft (0 m): Middle Eocene and younger overlap. ±2550 ft (±780 m): Cabaiguan* sequence consisting of the Maastrichtian Pen ˜alver and possible Via Blanca formations. ±3200 ft (±980 m): Domingo* sequence consisting dominantly of serpentine (only to the south of the field). ±4660 ft (±1420 m): Major thrust under the Domingo* sequence to the south and Cabaiguan* sequence to the north. ±4660 ft (±1420 m): Cifuentes* belt, where the Ronda*, Santa Teresa*, Carmita*, and Amaro* formations are represented in a very complex, chaotic, and structural situation. ±6560 ft (±2000 m): Major thrust, with slivers of Vega* and Rosas* formations caught along the thrust plane overlying the Campanian – Maastrichtian Lutgarda formation. ±6560 – 11,940 ft (±2000 – 3640 m): Strongly deformed and fractured (60 –908 dips) Las Villas* and/or southern Rosario belt, with a unit similar to the Oxfordian Francisco Formation, with quartzose clastics at the base, overlain by the Jagu ¨ita* and Caguaguas* (equivalent to the Artemisa Group), and the Capitolio*, Ramblazo*, and/or Constancia formations (equivalent to the Polier Group). This subsurface section is very important as it proves the structural superposition of the Cabaiguan*, Domingo*, Cifuentes*, and Las Villas* belts.

Varadero – Varadero Sur – Marbella – Marbella Mar – Cantel – Chapellin – Guasimas: — These fields rim the northwest of Cardenas Bay, near Hicacos-1, and a representative section (Varadero) encountered is as follows: 0 to ±2130 ft (0 to ±650 m): Middle Eocene and younger overlap. ±2130 ft (±650 m): Aptian to Maastrichtian Cifuentes* belt section. ±4530 ft (±1380 m): Major thrust fault. ±4530 – 8200 ft (±1380– 2,500 m): The Oxfordian to Valanginian part of the Las Villas* belt section is overlain by the lower middle Eocene Vega* and Rosas* formations. Note that the Oxfordian to Valanginian part of the section correlates with the pre-Eocene of the Gulf Hicacos-1 well.

Jurassic Platform to Cretaceous Deep Basin Province Discussion The part of the depositional basin represented by the Las Villas* and possibly the Placetas* and Cifuentes* belts accumulated shallow-water carbonates during the late Kimmeridgian through the middle Tithonian up to a thickness of at least 2100 ft (640 m) of sediments. Near the close of the Jurassic, there must have been an increase in the rate of subsidence south of the Yaguajay* belt because carbonate bank sedimentation did not keep pace with the deepening of the basin. There might have been other factors preventing the continuation of the buildup of these banks, such as changes in oceanic circulation brought about by the widening of the rift between North and South America. Sedimentation continued under deep-water (oceanic?) conditions during the entire Cretaceous to the middle Eocene. This sedimentation consisted mostly of calcareous nannoplankton during the Neocomian and Aptian. From the Albian through the Turonian, increasing amounts of silica were present in the form of radiolaria and volcanic-derived material. It should be noted that the change from Capitolio* and Calabazar* to type 3 Ronda* and Santa Teresa* indicates an increase in anoxic conditions. The increase in cherts indicates a deepening through the carbonate compensation zone. A total of not more than 2400 ft (730 m) of pelagic carbonates and cherts were deposited in deep waters from the upper Tithonian through the Cretaceous.

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During the same interval of time, some 9000 ft (2750 m) of shallow-water carbonates were deposited on the carbonate platform, suggesting that in the Las Villas* belt, the water depth was more than 6000 ft (2000 m) by the Late Cretaceous. Initially, the rate of basement subsidence under the carbonate platform would have been equal to that under the basinal sediments. As sedimentation continued, basin subsidence must have been much greater than under the banks. During the Neocomian through Aptian, the basin must have been broken by horsts and grabens, as indicated by the localized presence of coarse detrital material apparently deposited in deep water. There are clasts of Upper Jurassic and Neocomian carbonates derived from the south in the southern Las Villas* belt and pre-Neocomian metamorphic and granodiorite detritus of local origin in the southern Cifuentes* belt. From the Aptian onward, an increasing contribution of fine to coarse material was apparently derived in large part from the carbonate banks to the north and deposited as turbidites interbedded with pelagic deposits. The increase in amount of radiolarian cherts indicates a great deepening of the water. Through the Campanian and Maastrichtian, turbidites derived from the north dominated the sedimentation. However, at the same time, toward the south, erosion and redeposition of the Santa Teresa* cherts and the presence of igneous-derived material in the Amaro* Formation indicated early orogenic activity there. In the lower –middle Eocene, the northern half of the basin continued to receive the Sagua* Formation detritus from the carbonate banks, together with those derived from the early deformation and faulting of the Yaguajay* and Las Villas* belts. Finally, the Eocene San Martin* and lower Vega* formations reflect the proximity of the advancing basic igneous-volcanic province thrust sheet. The erosion off that sheet culminated with the deposition of the wildflysch of the upper member of the Vega* (Rosas*) Formation. The entire deep-water nature of this basin is remarkable. Despite the possibility of a Coniacian and Paleocene hiatus, the presence of reworked intraformational detritus, and the direct evidence of unconformities, no indication of deposits of shallow-water origin exist other than turbidites. The possibility of submarine erosion on a regional scale has to be considered because subaerial erosion is unlikely. As has already been mentioned, the entire deep-water Upper Jurassic and Cretaceous section has great lithologic and faunal affinities with the Tethys, suggesting a direct connection with the Tethyan Mediterranean, es-

pecially if one considers the dissimilarity with sections of equivalent age in North and South America. Finally, it should be emphasized that all the contacts between Las Villas*, Placetas*, and Cifuentes* belt deep-water lithologies and those of the basic igneousvolcanic province are tectonic. It is important to attempt an estimate of the original width of the basin in which the sediments of the Las Villas*, Placetas*, and Cifuentes* belts were deposited. As previously mentioned, the Las Villas* belt could have been 50 km (31 mi) in width; the Placetas* belt could have been some 5–10 km (3–6 mi), and the Cifuentes* belt, considering the three plates, could have been some 15–20 km (9–12 mi). Therefore, the basin was a minimum of about 70–80 km (43–49 mi) wide. This distance is only the present estimated original width of the belt’s outcrops without allowing any distance for the facies to change from belt to belt. Arbitrarily, one could allow another 70 km (43 mi) to take care of the overriding of the thrust sheets and the facies changes from belt to belt. As will be described below, large outcrops of Ronda* and Jaguita* formations along the Tuinicu fault exist between the Cabaiguan* sequence and the Manicaragua granodiorite, 25 km (15 mi) south of the southernmost exposure of the carbonate belts. The basin width before deformation could, therefore, have been close to 150 km (93 mi). Intuitively, this distance is on the low side because the type of sediments in these belts suggests the scrapings, or remnants, of a much larger, deep-water, perhaps oceanic, basin. In La Habana and Matanzas, this province has been found only in wells and as far west as the Via Blanca field. Because of serious structural complications, thicknesses are only estimates. Despite problems with the published descriptions of the formations, some important points can be made: 1) The belts are continuous from central Cuba to western Cuba, with the Las Villas* belt (equivalent to the northern Rosario and possibly the Mogotes area) being the lowermost penetrated sheet. 2) The presence of Upper Jurassic Favreina sp. and Globochaetes alpina indicates that, during that time, shallow-water conditions existed uninterruptedly from central to western Cuba, suggesting a continuous basin, with evidence that in the Oxfordian, clastic sedimentation extended east as far as the Cardenas Bay, possibly extending farther east toward the Punta Alegre area (supporting the Jurassic origin of the exotics in the San Adrian and Punta Alegre formations).

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3) As in the rest of Cuba, the Late Jurassic and all of the Cretaceous were times of marked deepening of the basin, shown by the influx of nannoplankton. 4) The Aptian–Santonian appears to be less well represented than in other Cuban regions, and the Coniacian–Santonian has never been identified. 5) The Campanian–Maastrichtian is, like everywhere else in Cuba, characterized by carbonate detritus; however, in the subsurface upper plate of the Cifuentes* belt, there is a reported influx of terrigenous arkosic detritus suggesting the proximity of southern granitic highs, possibly similar to allochthonous Sierra Morena or La Rana, that has never been observed on outcrops—perhaps it belongs to another part of the section. 6) There is no report of middle Eocene carbonate conglomerates such as the Sagua* Formation, indicating that the Bahamas-type carbonate banks were farther away from the Las Villas* belt than in central Cuba. 7) Terrigenous flysch deposits derived from the destruction of the basic igneous-volcanic province characterize the upper Paleocene–middle Eocene, and culminate in the middle Eocene showing the chaotic wildflysch of the Rosas* Formation and Vieja Member of the Manacas Formation.

SOUTHWESTERN TERRANES This province is found in the Guaniguanico Mountains, the Escambray Mountains, the Isla de la Juventud, and as far east as the Asuncion area in Oriente. The southwestern terranes do not show as clear a continental margin succession of facies as do the northcentral terranes. They show, to a greater or lesser extent, a succession of facies that include silicate clastics, bank carbonates, and deep-water pelagic environment. For convenience, they can be generally subdivided into metamorphics and unmetamorphosed sediments. The unmetamorphosed rocks occur in the Guaniguanico Mountains, whereas the metamorphics are found along the southeastern edge of the Guaniguanico Mountains (along the Pinar fault), the Isla de la Juventud, the Escambray massif in central Cuba, and Asuncion in extreme eastern Cuba.

Nonmetamorphics Guaniguanico Mountains Because of the spectacular exposures, Pinar del Rio has historically received more attention from the geo-

logic community than central Cuba. As a result, the discussion here will be based heavily on the published literature, especially on the work of Andrzej Pszczo´lkowski, with references to Gulf’s or other works when pertinent. Several units were first described and named by DeGolyer (1918), Lewis (1932), and Palmer (1945). As in central Cuba, these units turned out to cover a larger time span and may be more complex than originally thought. Although western Cuba was not mapped in detail by Cuban Gulf, P. B. Truitt conducted extensive reconnaissance during 1955–1956, in which he established the basis for the presently used structurofacies zones nomenclature and resolved much of the structural and stratigraphic confusion that existed at the time. It should be noted that one of the important aspects of Truitt’s work is that it was done after the bulk of Gulf’s work in central Cuba had been conducted, and Truitt had been one of the main participants in that study; he was therefore ideally suited to compare the two areas. His regional correlations are still valid (central Cuba names such as Carmita and Santa Teresa formations are presently widely used in Pinar del Rio). In addition, the samples were described, and their fauna were identified by P. Bro ¨ nnimann’s laboratory. During the late 1950s, C. W. Hatten mapped the central part of the Sierra de los Organos, and much of the present structural and stratigraphic concepts and terminology of the area are based on his 1957 California Co. unpublished reports, nationalized by the Cuban revolution. He recognized several peel nappes and identified what is still believed to be the most autochthonous of all the exposed structural elements: the pons autochthon. Since 1970, a team of geologists from the Polish Academy of Science has been involved in mapping and working out the details of the stratigraphic sequences of this area, notably among them A. Pszczo´lkowski, K. Piotrowska, and J. Piotrowski. R. Myczynsky (1987a, b), Myczynsky and Brochwicz-Lewinski (1981), and Myczynsky and Pszczo´lkowski (1987) studied the Ammonite fauna. Consequently, and unlike other areas in Cuba, much has been recently published on Pinar del Rio. In the last several years, Pszczo´lkowski (1999) has made some important and needed revisions to the published nomenclature. The revised nomenclature is used here. As will be seen below, although very important information can be derived from this region, the distribution of exposures and the structural complexities make it very difficult to reconstruct the geologic history from these data alone.

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In contrast with central Cuba, western Cuba has a thick and extensive section of Jurassic and Cretaceous continentally derived clastics, and the Cretaceous carbonate platform is poorly represented. In general, western Cuba has not suffered as much from the nomenclatural nightmare that has afflicted central Cuba, but problems remain. Truitt (1956a, b), the first to use the concept of belts in Pinar del Rio, subdivided the province into the sedimentary Organos*, Rosario*, and Cacarajı´cara* belts and the basic igneousvolcanic Bahia Honda* belt. Pardo (1975) used the same nomenclature. In addition, Truitt named an informal unit: the ‘‘northwestern Rosario* belt,’’ that was also recognized by Hatten (1957), who named it ‘‘La Esperanza.’’ This terminology is, in large part, still in use today, although it has been modified, enlarged, and further subdivided. Pszczo´lkowski (1999) recognizes four facies-tectonic zones: La Esperanza (which is equivalent to Truitt’s northwestern Rosario*), Bahia Honda, Cordillera de Guaniguanico, and Los Palacios Basin. The Cordillera de Guaniguanico is subdivided into Sierra de los Organos, Cangre, northern Rosario, southern Rosario, and Guajaibon-Sierra Azul belts as major subdivisions and a large number of smaller tectonic units. Each one of the smaller units is a separate thrust sheet with a characteristic stratigraphic sequence. The Guajaibon-Sierra Azul belt is equivalent to Truitt’s Cacarajı´cara* belt. Pushcharovsky et al., 1988, show the Bahia Honda, Sierra del Rosario, Sierra de los Organos, La Esperanza and Cangre facies-structural units, and the Los Palacios Basin. The Cangre unit is the metamorphosed southern part of the Sierra de los Organos belt (along and northwest of the Pinar fault), and the lower part of the mostly younger Tertiary Los Palacios Basin is synonymous with Truitt’s southern Bahia Honda* belt. Unfortunately, a serious nomenclatural problem exists: Truitt’s original Rosario–Los Organos belt subdivision was more physiographic than structurostratigraphic and only partially follows the Pardo ‘‘belt’’ or Hatten-Meyerhoff’s ‘‘faciesstructural unit’’ definition (in 1957, Hatten did not use facies-structural units in Pinar del Rio). As will be seen below, from a structural and facies point of view, a large part of the outcrops included by Truitt and others in the Los Organos belt really do belong to the Rosario belt. In this study, an attempt will be made to use a facies-structural nomenclature without creating unnecessary confusion. With the exception of Sierra de los Organos, the names used will be the same as the ones presently used in the Cuban literature or on maps and will be modified to consistently reflect

the structure and stratigraphy. For the sake of uniformity, the major stratigraphic-structural subdivisions will be named ‘‘belt,’’ and because of the structural complexity, the term ‘‘unit’’ will be used for groups of strata that belong to one individual thrust sheet. The names of the major subdivisions used by Pszczo´lkowski (1999) will be used throughout; however, Pszczo´lkowski’s subdivisions (which he calls ‘‘belts’’ but others call ‘‘facies-structural zones’’) will be modified as follows: The Sierra de los Organos belt will be subdivided into the Mogotes area: all the units of the Sierra de los Organos belt minus the Alturas de las Pizarras del Sur unit the Alturas de las Pizarras del Sur area: the Alturas de las Pizarras del Sur unit As will be seen later, the Mogotes area is a window through a thrust sheet of San Cayetano Formation that is partially included in the southern Rosario belt. So far, there is some evidence that the maximum thickness of San Cayetano does not coincide with the thickest Mogote belt carbonates. It appears as if the San Cayetano depocenter was south (restored position) of the Mogotes carbonates depocenter. Figure 85 shows the correspondence of the several nomenclatural systems used in western Cuba. The distribution of the major stratigraphic-structural subdivisions is shown in Figure 86. Figure 87 is a pre– upper Eocene correlation chart of the northwestern terrane units in western Cuba. Pinar del Rio is the area where the Cuban orogen extended between the Bahamas and Yucatan platforms, and consequently, much of the section younger than Late Jurassic consists of rocks originating in a deepwater environment. Here, many authors assume that the general thrusting must have occurred northward toward the deep-water facies of the southern Gulf of Mexico; however, contradictions exist. Truitt (1956a, b) was convinced that the thrusting was directed southward. In Pinar del Rio, it is difficult to establish a natural basinal succession on account of the apparent opposing directions of thrusting or nappe emplacement and the lack of a well-defined continental margin to the north. As will be seen below, some remnants of carbonate banks exist, caught in the thrusting, in the northwestern as well as the central part of the province. These suggest a partial shallow-water link between the Bahamas and Yucatan or perhaps small shallow-water banks surrounded by a deep-water environment (similar to the eastern end of the Bahamas).

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Although the tectonics will be discussed in Chapter 5 of this publication, most authors (Hatten, 1957; Rigassi-Studer, 1963; Piotrowska, 1975, 1978; Pszczo´lkowski, 1971, 1977, 1994a, 1999) agree that (1) part of the section present in the north of the Los Organos region has been displaced northward and thrust over the La Esperanza belt; (2) the southern and lower part of the section of the Los Organos region has also been thrust northward over the carbonates that form the core of the same region; and (3) the Rosario belt is the lateral equivalent of the La Esperanza belt and also of the northern part of the Rosario belt, which has been thrust over the rocks in the Los Organos region. The present general opinion (first published by Iturralde-Vinent, 1994) is that all major thrusting was directed northward and that the basic igneousvolcanic Bahia Honda belt originated south of the sedimentary belts. Regardless, the thrusting directions in Pinar Del Rio have been the subject of much discussion. The major belts that form most of the exposures of the Cordillera de Guaniguanico will be described in the following order: (1) Gujaibon – Sierra Azul, (2) northern Rosario belt, (3) La Esperanza belt, (4) southern Rosario belt, and (5) Sierra de los Organos belt that, in this study, has been subdivided into the Mogotes and the Pizarras del Sur (including Cangre) areas. As will be discussed below, this is not necessarily the original depositional order.

FIGURE 85. Western Cuba belt nomenclature.

Guajaibon–Sierra Azul Belt Sediments belonging to the carbonate platform were recognized in Pinar del Rio by Truitt (1956a, b), who defined the narrow and discontinuous Cacarajı´cara* belt. Herrera (1961) also reported these carbonates. Later workers do not seem to have realized the similarity to the Yaguajay* belt of Las Villas province and included these rocks in the Quin ˜ones unit under the name of Guajaibo´n Formation. Pszczo´lkowski (1978) realized that although the Guajaibo´n Formation was placed in the Quin ˜ones sequence, it should be considered as a distinct tectonic unit. In 1987, as well as in his most recent article, Pszczo´lkowski (1999) considers the Guajaibo´n Formation to belong to a separate unit he called the Guajaibon –Sierra Azul. Although Truitt’s Cacarajı´cara* belt has priority, the Guajaibon – Sierra Azul name will be used in this study. Massive Jurassic shallow-water carbonates have been drilled in EPEP Pinar-1 in the Mogotes area; however, from the descriptions, the types of carbonates

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FIGURE 86. Western Cuba: southwestern terrane generalized geologic map.

FIGURE 87. Correlation chart, southwestern terrane, western Cuba.

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FIGURE 88. Western Cuba, Guajaibon – Sierra Azul belt. are more akin to the lower Las Villas* than to the Yaguajay* belt. For this reason, they will be described under the section on clastics and platform to deep basin province. The Guajaibon–Sierra Azul belt extends as a discontinuous belt for 20 km (12 mi) from San Juan de Sagua to the east-northeast. Its maximum width is 1.5 km (0.9 mi) (see Figure 88). It consists of steeply northward-dipping fault blocks; one of them, the Pan de Guajaibo´n, is the highest elevation in Pinar del Rio. It appears not to have been studied in detail because of difficult access. In Pushcharovsky et al. (1988), it is shown as the Albian–Cenomanian Guajaibo´n Formation that consists of light-gray massive limestones, some being fragmental and richly fossiliferous; some local dolomitization is present. Miliolids, algae, and mollusks are abundant. Bauxite has been reported in the Cenomanian. Truitt (1956a, b) was more precise in characterizing this belt’s lithologies and estimated the total exposed thickness at not more than 1000 ft (300 m). Pszczo´lkowski (1978) gives a thickness of 1250 ft (380 m) at the Pan de Guajaibo´n type section and estimates a maximum of 1650 ft (500 m). The following is Truitt’s description (see Figure 89).

Vin ˜ as* Group.— The Vin ˜as* Group consists of the typical Upper Jurassic to Albian Puntilla* or Bartolome´* Formation lithologies described under the Yaguajay* belt. One sample contained faunas with Jurassic affinities. It is included in the Guajaibo´n formation by Pszczo´lkowski (1978) and Pushcharovsky et al. (1988). Camaco* Formation.— This formation, also included in the Guajaibo´n Formation, is of Cenomanian to Santonian age, is present in its typical development of white, porous algal, and miliolid limestones. Pszczo´lkowski (1987) reports Rotalipora sp., Ticinella sp., Hedbergella sp., and Preaglobotruncana sp. from the upper part of his Guajaibo´n Formation, indicating a lower Cenomanian age. The Manacas Formation overlies this unit with unconformity. Remedios*(?) Formation. — This unit has not been specifically identified in this belt. The presence of Maastrichtian faunas reported by Pszczo´lkowski (1978) in the Guajaibo´n Formation was not confirmed; however, the presence of abundant Remedios* Formation clasts in Eocene conglomerates of the Bahia Honda belt, immediately to the north, as well as in the Cacarajı´cara Formation to the south, suggest its presence, or that it was deposited and subsequently eroded. It must be emphasized that the Gulf’s Remedios*

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FIGURE 89. Stratigraphic section: Guajaibon – Sierra Azul belt.

Formation (as opposed to the general Remedios lithology) has a characteristic Paleocene microfacies easily recognizable in clasts. Manacas Formation. — This name includes several related lithologic units with highly variable thicknesses. They range from 300 to ±1500 ft (100 to ±500 m), of basic igneous-derived sandstone, and shales, argillaceous red to white limestones (Pica Pica Member), and coarse and medium heterogeneous limestone (and chert) conglomerates and orogenic

conglomerates containing blocks of ultrabasic and basic igneous, volcanic, and sedimentary rocks in a clay matrix (Vieja Member). This unit was named Quin ˜ones* Formation by Truitt (1956a, b), who assigned it to the Maastrichtian. Hatten (1957) named the same flysch in Los Organos belt the Pinar Group (including the Pica Pica and Manacas Members, the ‘‘Vieja wildflysch,’’ and the ‘‘Canaletes chert’’) and named part of Truitt’s Quin ˜ones* the Cascarajı´cara (not Cacarajı´cara as presently

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spelled) Formation and considered them lower Eocene and middle to upper Eocene, respectively. Pszczo´lkowski et al. (1975) considered the Pinar Group name invalid and redefined it as the Pica Pica Formation, assigning it to the Paleocene to middle Eocene. Originally, the Cacarajicara Formation was considered to be in part equivalent to the Pica Pica; however, Pushcharovsky et al. (1988) and Pszczo´lkowski (1986a, b) consider it as a distinct unit of Maastrichtian age. In his most recent article, Pszczo´lkowski (1999) follows the current usage, sanctioned by the Cuban Commission of the Paleogene, of naming the unit Manacas Formation. Pushcharovsky et al. (1988) call it the Pica Pica (Manacas) Formation and includes in it the Vieja wildflysch. This does not agree with Hatten’s (1957) original definition of the Manacas Formation. This flysch occurs in all the structural units of the Sierra de Guaniguanico, with a variable character reflecting the underlying stratigraphy. In this belt, it has its thickest development and separates the bank carbonates from the Bahia Honda area Cabaiguan* sequence rocks. It contains a large proportion of basic igneous-volcanic detritus. Compositionally and temporally, this unit is similar to the lower–middle Eocene Vega* Formation of central Cuba, although it is considered to extend into the upper Paleocene. The flysch problem will be further discussed, and the Manacas Formation will be more completely described under the northern Rosario belt section. Guajaibon – Sierra Azul Belt Discussion. — Although essentially nothing has been written about it in the recent literature (except the recognition of the existence of bank carbonates), the presence of the typical Yaguajay* belt lithologies structurally sandwiched between the basic igneous and volcanics of the Bahia Honda belt, and the pelagic sediments of the northern Rosario belt, is of extreme importance. Although in central Cuba, the Domingo* sequence can be found north of the Yaguajay* belt, the presence of Cretaceous and possible Upper Jurassic platform carbonates 280 km (173 mi) west of the westernmost known occurrences of Bahamas Bank lithologies (Gulf Blanquizal-1 and Gulf-Chevron Cay Sal-1) is surprising, although similarity of facies and fauna should not be automatically interpreted as suggesting paleogeographic continuity. The Quin ˜ones unit of the northern Rosario belt dips northward under the Lower to Upper Cretaceous platform carbonates of the Guajaibon–Sierra Azul belt and consists almost entirely of a Neocomian through lower Maastrichtian pelagic section related to the Cifuentes* belt of central Cuba. The section is right-

side up, and the faulting direction could be either northward or southward. As already mentioned, the Guajaibon–Sierra Azul belt is similarly right-side up under the north-dipping basic igneous-volcanic Bahia Honda belt. It should be noted that its thickness is only a fraction of that of the Yaguajay* belt, with only parts of the Lower and Upper Cretaceous represented. Regardless of the thrusting direction, these outcrops suggest a Cretaceous, prethrusting, basic igneousvolcanic–carbonate platform–deep basin succession. If the thrusting responsible for the present configuration of the belts was from north to south, then a source of volcanics must have been present to the north, within the carbonate bank province, which would be surprising. If the thrusting was from south to north, then carbonate banks were far removed from the Bahamas, south of the deep basin and north of the volcanics. The presence of bauxite in the Cenomanian suggests a proximity to volcanic activity. Perhaps the Guajaibon–Sierra Azul belt represents the remnants of Jurassic – Cretaceous isolated banks, not connected to the Bahamas and surrounded by a deep-water environment; this is the situation with the Jurassic limestones of the Catoche Knoll or the present Bermuda Island. The age of the base of these banks is somewhat questionable, but is believed to be at least Early Cretaceous. At any rate, the banks must have been fairly extensive and continuous to have supplied the material for the Cacarajı´cara and Manacas formations and other related detritals of the northern Rosario and Bahia Honda belts. Perhaps these banks were deposited over the continuation of the Lower Cretaceous Rancho Veloz and La Rana basement highs. As an explanation for the position of the carbonate banks, which is the reverse from that of central Cuba, one can invoke opposing thrusting directions (northward thrusting of the Bahia Honda belt over the carbonate bank, followed by southward thrusting of both over the previously thrusted complex of deep-water basin sediments), but this would considerably complicate the structural picture.

Northern Rosario Belt The name Rosario was derived from a range characterized by low rounded topography caused by the presence of thin-bedded cherty and chalky limestones, and distinguished from the Los Organos (The Organs) Mountains characterized by sheer cliffs of massive, thick-bedded, limestone in a mature karst topography (mogotes). The original Rosario belt has been subdivided for structural and stratigraphic reasons into

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FIGURE 90. Western Cuba, northern Rosario belt. a northern and southern Rosario belt. The northern Rosario belt corresponds quite well to the original definition of belt or facies-structural zone. The sequence of this subdivision of Truitt’s Rosario* belt was defined by Pszczo´lkowski (1977, 1978, 1994a, b, c, d; 1999). The northern Rosario belt, as shown in Figure 90, has been subdivided into several low-angle, mostly north-dipping thrust sheets or units; from lower to higher, these are as follows: 1) Belen Vigoa unit. This is the lowest of the sequence and overlies the southern Rosario belt. It is overlain in the east by the Naranjo and in the west by the Cangre units. 2) Naranjo unit. It generally overlies the Belen Vigoa unit and, to the east, the southern Rosario belt. From east to west, the Dolores, La Serafina, and Cangre units overlie the Naranjo. 3) Dolores unit. It is limited to the eastern part of the northern Rosario belt, where it overlies the Naranjo unit and is overlain by the La Serafina unit. 4) La Serafina unit. It is also limited to the eastern part of the Rosario belt and is mostly underlain by the Dolores unit and overlain by the Cangre unit.

5) Cangre unit. It is rather extensive and covers twothirds of the northern Rosario belt. From east to west, La Serafina, Naranjo, Belen Vigoa units, and the southern Rosario belt underlie the Cangre. Between the Cangre and the Naranjo units, a large elongated serpentine body exists. Everywhere, the Sierra Chiquita unit overlies the Cangre unit. The name Cangre has been used for the metamorphosed equivalent of the Alturas de las Pizarras del Sur area, or unit, of the Los Organos belt. 6) Sierra Chiquita unit. Extending for the entire length of the northern Rosario belt, it is underlain by the Cangre unit and the southern Rosario belt to the west. It is mostly overlain by the Quin ˜ ones unit and in the east by the Bahia Honda area of the Cabaiguan* sequence. 7) Quin ˜ ones unit. It is the highest unit of the sequence. It extends for 45 km (27 mi) east-northeast of San Juan de Sagua immediately south of the Cacarajı´cara* belt. In addition, there is the Martin Mesa window, consisting of northern Rosario belt sediments surrounded by basic igneous and volcanics of the northern Bahia Honda area and outcropping between Mariel and

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FIGURE 91. Stratigraphic section: northern Rosario belt.

Guanajay in western Habana province. The rocks exposed in the Martin Mesa window are tectonically highly crushed and show no direct structural relationships with any of the units of the northern Rosario belt. The stratigraphic sections of the northern Rosario belt and the Martin Mesa window in western Habana province are described below.

Northern Rosario Belt (Sensu Stricto). — This belt extends for 65 km (40 mi) from south of the Sierra de Cajalbana to Cayajabos, along the south flank of the Cacarajı´cara* belt. It has a wedge shape and is bound by what are considered to be major north-dipping faults. It fits the definition of belt in that it has a set of characteristic sequences and is bounded by faults. The section is as follows (see Figure 91).

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Basement. — El Sabalo Formation: —El Sabalo Formation consists of 500 to more than 650 ft (150 to more than 200 m) of an interbedding of 1) Basic igneous rocks ranging in thickness from ±1 to 23 ft (±0.3 to 7 m) in thickness, consisting of dark-green, massive diabases and basaltic flows exhibiting pillow structures, mostly toward the upper part of the layer. Sometimes, the basalts are spilitized. In some cases, the pillows contain vesicles. These volcanics form 60–80% of the section. The chemical composition of these rocks suggests oceanic tholeiites. 2) Dark-gray to black, weathering light-gray to gray, well-bedded to finely laminated limestones up to 16 ft (5 m) in thickness. Some samples contain abundant G. alpina and phosphatic (fish) remains. Didemnoides moreti, Didemnum carpaticum, Didemnum minutum, ‘‘Colomisphaera’’ cf. pieniniensis, and ‘‘Colomisphaera’’ cf. nagyi have also been found. Although this assemblage is not very diagnostic, its local occurrence suggests a pre-Tithonian, Oxfordian(?)–lower Kimmeridgian age. These carbonates were deposited under reducing conditions. 3) Well-bedded calcareous shales. There are occasional marly limestones containing fine pyroclastic material. Occasional tuffs and rare thin siliceous lenses are associated with the volcanics. This unit is well developed and present only in the Naranjo and Belen Vigoa units. It is believed to be equivalent to the Francisco (in which a basalt has been identified) in the southern Rosario belt, and it also correlates and show similarities with the Jagua Formation in the Cangre belt. It is also believed to have similarities with the basalts associated with the base of the La Esperanza Group in the western La Esperanza unit, although these have been attributed to the Tithonian–Berriassian. This section is probably related to the Nueva Maria (Ronda*) Formation section in the Sierra de Camajan that also shows Tithonian limestones in contact with tholeiitic basalts. Like the southern Cifuentes* belt in central Cuba, it could well represent a sliver of basement belonging to the transition between the northern and southern Rosario belts caught in the thrusting. Vin ˜ ales group. — This term is not being presently used (Pszczo´lkowski, 1999) because it is too general, but appears widely in the literature. It is mentioned in this publication for historic reasons.

DeGolyer (1918) proposed the name ‘‘Vin ˜ ales limestone’’ for all the ‘‘mogote-forming’’ limestones of the Sierras de Los Organos and Rosario. No type section was given. Truitt (1956a, b) and Hatten (1957) limited the Vin ˜ales Formation to the Los Organos belt. Herrera (1961) elevated the Vin ˜ales to Group, including in it many limestone types in both the Los Organos and the Rosario belts. This move was not justified because the original intent was to separate the mogote-forming, shallow-water massive Jurassic limestones (San Vicente Formation) from the deep-water, thin-bedded cherty limestone of Jurassic and Cretaceous age. These two types of limestones give the distinctive physiographic character to the Los Organos and Rosario belts. In outcrops, it consists of a maximum of 2625 ft (800 m) of limestone with minor quantities of sandstones, cherts, and shales. It is present in the entire Guaniguanico Mountains. It has been subdivided into the Guasasa, Pons, Artemisa, Polier, and Lucas formations. The Artemisa Formation is restricted to the Rosario belts, and the Polier and Lucas formations are restricted to the northern Rosario belt. Artemisa Formation. — The Artemisa Formation consists of 150 – 1300 ft (50 – 400 m) of well-bedded fine-grained limestones, calcilutites, calcarenites, and a few calcirudites. In a few places, thin beds of radiolarian chert and some marly shales exist. At the base of the formation are occasional fine-grained sandstones and siltstones. The limestones emit a strong petroleum odor when fresh (dry or wet), and asphalt is commonly found in fractures. The Artemisa Formation contains three members: San Vicente, La Zarza, and Sumidero. Of these, only La Zarza and Sumidero are found in the northern Rosario belt, and only Sumidero can be recognized in all the sections. This formation was named the ‘‘Artemisa Limestone’’ by Lewis (1932), the ‘‘San Andre´s formation – eastern part’’ by Vermut (1937), ‘‘Aptychus limestone’’ by Palmer (1945), Artemisa Formation by Truitt (1956a, b), and the Rosario limestone by Hatten (1957). In contrast to the mogotes-forming Guasasa Formation, the Artemisa forms low to moderate rolling hills. La Zarza Member: — La Zarza Member consists of 250 –650 ft (80 –200 m) of thin-bedded micritic limestones interbedded with thin shales overlain by more massive beds of gray fine-grained limestones interbedded with bioclastic limestones and coquinas containing ammonites and aptychi. Some parts of the section are tectonically disturbed. Aptychi are present throughout but rare.

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The fauna consists of Cubaspidoceras sp., Microsphinctes sp., Pseudolissoceras sp., Butticeras sp., Paradontoceras sp., Corongoceras sp., Protoncyloceras sp., Dickersonia sp., and Vin ˜ alesites sp. They, together with Chitinoidella sp., indicate an age ranging from the late middle Oxfordian–early upper Oxfordian to Tithonian. The presence of Calpionella sp. in the upper part of the section indicates that La Zarza Member reaches the upper Tithonian or Berriasian. This unit grades into the overlying Sumidero Member. It is equivalent to the upper Pimienta Member of the Jagua Formation and to the San Vicente, El Americano, and lower Tumbadero members of the Guasasa Formation in the Mogotes area. It is equivalent to the Jagu ¨ ita*, Caguaguas*, and lower Capitolio* formations of central Cuba. However, it appears to have been deposited in much deeper water than the Jagu ¨ ita*. Sumidero Member:— The Sumidero Member consists of 150 – 650 ft (50 – 200 m) of a succession of micritic pink and brown limestones, interbedded lightgray limestones and thin cherts, and finally, toward the top, gray to bluish gray micritic limestones interbedded with thick, radiolarian cherts and laminated limestones. Abundant calcified radiolaria exist. An abundant fauna exists characterized by Calpionella alpina, Calpionella elliptica, Crassicolaria brevis, Tintinnopsella cf. carpathica, Tintinosporella longa, Remaniella cadischiana, Calpionellopsis simplex, Calpionellopsis oblonga, and Calpionellites darderi. In addition, the ammonites Thurmaniceras cf. novhispanicus and Karsteniceras cf. subtilis have been identified. The age is considered Berriasian to Hauterivian. The contact with the overlying Polier Formation is conformable. This unit is equivalent to the upper part of the Tumbadero and the Tumbitas Members of the Guasasa Formation in Los Organos belt and to the Capitolio*, Sabanilla*, and Ronda* formations of central Cuba. Polier Formation. —The Polier Formation consists of thin-bedded micritic limestones interbedded with sandstones and shales. The sandstones are best developed in the Sierra Chiquita and Cangre units, where the formation is 650 – 1000 ft (200 – 300 m) in thickness, decreasing to less than 100 ft (30 m) southward in the Belen Vigoa unit. This unit is absent in the southern Rosario belt. The lower part of the formation consists of thin-bedded gray micritic limestones interbedded with claystones and sandstones. The sandstones are thin bedded, gray to dark gray, hard, finegrained with calcareous cement. They show organic and inorganic markings at the base, graded bedding,

and horizontal and cross-laminations. Some of the sandstones reach 3 ft (1 m) in thickness. The dominant component is poorly rounded quartz with subordinate plagioclases and muscovite. They are considered to be turbidites. This formation was named by Pszczo´lkowski (1977) and was formerly included in the upper part of the Artemisa Formation. Truitt (1956a, b) recognized it as a separate unit and named it Soroa Formation. The base of the Polier Formation has yielded Calpionellopsis simplex, Calpionellopsis oblonga, and Calpionellites sp. The Polier Formation contains a rich ammonite fauna, including Partschiceras infundibulum, Lytoceras cf. stephanensis, Biasaloceras cf. subsequens, Macroscaphites cf. yvani, Leptoceras cf. studeri, Hamulinites parvulus, and Karsteniceras polieri, which indicates a Valanginian–Aptian age, although most of the deposits are believed to be Hauterivian–Barremian. In the upper part of the Polier Formation is a distinct lithologic unit named the Roble Member. Roble Member: —The Roble Member consists of ±80 ft (±25 m) of thick- to medium-bedded, mediumgrained quartz sandstone. Most of the sandstone beds show graded bedding, cross-bedding, current marks, groove marks, and prod casts indicating an origin as turbidites coming from the northwest and north. Some fine interbeds of shales exist, as well as a few micritic limestones in the middle part of the member. At the top of the member is a 3-ft (1-m) bed of detrital limestone. This unit contains only poorly preserved, unidentifiable fossils, and the age is considered Aptian–Albian based on the stratigraphic position. Although the contact is sharp, the Roble Member is conformable with the overlying Santa Teresa Formation. The Polier Formation, especially the Roble Member, shows an influx of quartz sand with muscovite. There could be a relationship with the deep-water Constancia* Formation of central Cuba of Aptian age, which is quite unique in showing quartz and abundant muscovite. It is also very similar to and coeval with the La Esperanza Formation of the La Esperanza belt. Lucas Formation. —The Lucas Formation (named by Pszczo´lkowski, 1977) consists of 650–1000 ft (200– 300 m) of thin-bedded, gray micritic limestones intercalated with hard, calcareous shales and marly shales. The limestones contain abundant aptychi, a few ammonite imprints, and calcified radiolaria, and the unit is considered of upper Hauterivian to Barremian age. It is comformably overlain by the Santa Teresa Formation. It is in part equivalent to the Polier Formation and is restricted to the Sierra Chiquita and Quin ˜ones units. It is also equivalent and lithologically similar

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to the Capitolio*, Ramblazo*, and Ronda* formations of central Cuba. Buenavista group.— This name is not in use at present (Pszczo´lkowski, 1999). It consisted of 650–1300 ft (200 – 400 m) of an association of three lithologies; cherts, limestones, and shales. This group was formerly named the Buenavista Formation by Pszczo´lkowski, 1977, 1978. It is subdivided into four formations; the Santa Teresa, Carmita, Pinalilla, and Moreno. The Buenavista Group was time equivalent to the upper Guasasa and most of the Pons Formation in the Mogotes area. In the Rosario belt, it was mapped by Truitt (1956a, b) as the Carmita* Formation of central Cuba because of its lithologic similarity and time equivalence, and he recognized the change to the dominantly chert Santa Teresa* Formation facies toward the Mogotes area. Santa Teresa Formation. — The Santa Teresa Formation consists of up to 130 ft (40 m) of green, thinbedded, and laminated radiolarian cherts and silicified argillite at the base, turning into red to reddish brown cherts toward the top. This unit, the name of which was originally established in central Cuba, was formerly named the Sabanilla Member of the Buenavista Formation and was included in the lower member of the now invalid Sierra Azul Formation by Pszczo´lkowski (1977, 1978). It is synonymous with the Panchita Formation of the La Esperanza unit. It was mapped as part of the Carmita* Formation by Truitt (1956a, b), although he recognized that locally, it was more similar to the Santa Teresa. This unit contains a fauna of Ticinella sp., indicating an Albian to lower Cenomanian age. A sample of the Polier Formation immediately below the Santa Teresa yielded Nannoconus wassalli and Nannoconus cf. carniolensis latus, indicating an Aptian age. A sample at the top of the formation yielded Rotalipora appenninica, Rotalipora cf. reicheli, Rotalipora cf. cushmani, Praeglobotruncana stephani, Praeglobotruncana cf. delrioensis, Hedbergella cf. delrioensis, and Schackoina sp., indicating an upper Cenomanian age. The age therefore ranges from the Aptian through the Cenomanian. It grades upward into an interbedding of limestones and cherts characteristic of the Carmita Formation, but in some units (mostly in the southern Rosario belt), it has been subject to erosion and is unconformably overlain by the Cacarajı´cara Formation. This formation appears in all the units of the northern and southern Rosario belts. The formation is equivalent to the Pons Formation of the Mogotes area. This unit is lithologically similar

to and partially correlates with the Santa Teresa* Formation (Cifuentes* belt) of central Cuba. Carmita Formation. — The Carmita Formation consists of 0 –230 ft (0 – 70 m) of an interbedding of micritic limestones, cherts, and detrital limestones, which are calcareous turbidites, with graded bedding, containing common fragments of organisms, and rare foraminifera. They also contain occasional detritus of angular quartz, sandstone, graywacke, and plagioclase. This unit, whose name was originally established in central Cuba, was called the ‘‘Limestone and Chert Member’’ of the Buenavista Formation by Pszczo´lkowski (1977, 1978). It was recognized and mapped as Carmita Formation by Truitt (1956a, b). This member is typical of the northern Rosario belt and is particularly well developed in the Sierra Chiquita, Cangre, and La Serafina units. It is only partially present because of erosion in the Belen Vigoa, Naranjo, and Dolores units. It is absent in the Quin ˜ones unit. The planktonic fauna indicates a Cenomanian – Turonian age; however, in the upper part of the formation, which is commonly barren of fossils (or only contains unidentifiable ones), a fauna of Archeoglobigerina cf. cretacea, Globotruncana cf. linneiana, and Rugoglobigerina sp. has been found, suggesting a Coniacian– lower Santonian(?) age. This unit is lithologically similar to and correlates with the Carmita* Formation (Placetas* and Cifuentes* belts) of central Cuba. Pinalilla Formation. — The Pinalilla Formation (originally named the Pinalilla Member of the now invalid Sierra Azul Formation by Pszczo´lkowski, 1977, 1978) consists of a 560-ft (170-m)-thick, massive, thickbedded, gray-green micritic limestone. The fauna consists of planktonic foraminifera and radiolaria that indicate a Turonian age. It is confined to the Quin ˜ones unit. The contact with the Santa Teresa and Moreno formations is sharp, but appears transitional. Moreno Formation. — The Moreno Formation consists of 0– 800 ft (0– 240 m) of argillite, polymictic sandstones, and marly detrital limestones. The lower part of the section is dominated by argillites interbedded with limestones. Toward the top, the limestones become rare, and sandstones and conglomerates containing clasts of volcanics, all interbedded with the shales, appear. Intercalations of green dacitic tuffs are also present. This formation was formerly named the Moreno Member of the Buenavista Formation and included in the upper member of the now invalid Sierra Azul Formation by Pszczo´lkowski (1977, 1978) and was included in the Carmita* Formation by Truitt (1956a, b).

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This member is well developed in the Cangre and Quin ˜ones units. It is present in all other units, with the exception of Belen Vigoa. The following microfauna has been identified: Dicarinella cf. concavata, Dicarinella cf. imbricata(?), Marginotruncana pseudolinneiana, Marginotruncana cf. marginata, Globotruncana mariei, Globotruncana arca, Globotruncana saratogensis, Globotruncana ventricosa, Globotruncana linneiana, Globotruncana cf. linneianamariei, Globotruncana cf. bulloides-linneiana, Globotruncana cf. tricarinata, Globotruncana cf. insignis-orientalis, Globotruncanita elevata, Globotruncana cf. elevata, Globotruncana stuartiformis, Globotruncana cf. stuartiformis, Globotruncana calcarata, Globotruncana cf. subspinosa, Globotruncana cf. stuarti, Rosita fornicata, Rosita cf. patelliformis, Archaeoglobigerina cretacea(?), Hedbergella monmouthensis, Hedbergella cf. crassa, Plummerita hantkeninoides(?), Rugoglobigerina cf. rugosa, Rugoglobigerina cf. pilula, Rugoglobigerina cf. pilula-rugosa, Rugotruncana sp., Hastigerinoides sp., Globotruncanella sp., Globigerinelloides sp., Schackoina cf. cenomana, Sulcoperculina cf. diazi, Sulcoperculina cf. globosa, Vaughanina cf. cubensis, Pseudorbitoides sp., Orbitoides(?) sp., Sulcorbitoides(?) sp., Nummoloculina heimi, Stomiosphaera sphaerica, Pithonella ovalis, Pithonella cf. trejoi, and Globochaete sp. This fauna indicates a Santonian(?) to Campanian age, but mostly Campanian. This formation exhibits an unconformable contact with the overlying Cacarajı´cara Formation. The Moreno Formation shows great similarity with the Corona* Formation of the Placetas* belt. In central Cuba, the Corona* Formation is considered Santonian to Maastrichtian and is equivalent to the Amaro* Formation. It could be, however, older than the Amaro* because the Amaro* is not present (eroded?) in the Placetas* belt, and the Corona* is overlain by younger Tertiary. Cacarajı´cara Formation. — The Cacarajı´cara Formation consists of 330–1475 ft (100–450 m) of limestone and chert breccia grading up into a coarse calcarenite. Most of the fragments consist of shallow-water limestones containing algae, rudists, echinoids, miliolids, and large foraminifera. The lower part of the formation, named the Los Cayos Member, can be chaotic and contain very large clasts; the limestone components can reach 4 ft (1.3 m) and are richly fossiliferous with benthonic foraminifera and rudists. A block of chert 16 ft (5 m) wide has been observed. Olistoliths of Santa Teresa Formation (formerly called the ‘‘upper chert’’ member of the Buenavista Formation) exist. The blocks are tightly packed with no visible matrix.

This unit was named Quin ˜ones* Formation by Truitt (1956a, b) and assigned to the Maastrichtian. Hatten (1957) named the same flysch in Los Organos belt the Pinar Group and named part of Truitt’s Quin ˜ones* the Cascarajı´cara (not Cacarajı´cara as presently spelled) Formation and considered them lower Eocene and middle to upper Eocene, respectively. The Pinar Group name was considered invalid by Pszczo´lkowski et al. (1975), who redefined it as the Pica Pica Formation and assigned it to the Paleocene to middle Eocene. Originally, the Cacarajicara Formation was considered to be in part equivalent to the Pica Pica; however, Pushcharovsky et al. (1988) and Pszczo´lkowski (1986a, b) consider it as a distinct unit of Maastrichtian age. It was formerly included in the now invalid ‘‘calcareous breccia,’’ ‘‘upper chert,’’ and Los Cayos members of the Buenavista Formation by Pszczo´lkowski (1977, 1978). Fragments of deep-water biomicrites, radiolarian cherts, dolomites, shales, sandstones, quartzites, and volcanics are also present. The terrigenous material forms up to 5%, and the volcanic fragments form up to 2% of the clasts. The matrix is sparse and consists of fine detritals. The upper part of the formation is fine grained and can be well bedded. The fauna consists of Omphalocyclus cf. macroporus, Globotruncana arca, Globotruncana bulloides, Globotruncana lapparenti, Globotruncana linneiana, Globotruncana ventricosa(?), Globotruncanita calcarata, Globotruncanita stuarti, Globotruncanita cf. conica, Rosita patelliformis, Rosita fornicata, Rosita cf. contusa, Gansserina ganseri(?), Globigerina stuarti, Rugoglobigerina scotti, Rugoglobigerina rugosa, Pseudotextularia elegans, Sulcoperculina cf. globosa, Sulcoperculina cf. diazi, Sulcoperculina dickersoni(?), Abathomphalus cf. mayaroensis, Racemiguembelina fructicosa(?), Globotruncanella havanensis, Globotruncanella minuta, Plummerita hantkeninoides, Lepidorbitoides sp., Pseudorbitoides sp., and Vaughanina sp., indicating an upper Maastrichtian age. The upper sedimentary contact of this formation with the Anco´n has been observed in a few sections; however, the contact is commonly tectonic. This unit is best developed and is thickest in the northern Rosario belt, where it outcrops continuously for 53 km (32 mi) in the Sierra Chiquita unit. It is absent in the Quin ˜ones unit. It correlates with and is lithologically very similar to the Amaro* Formation (Cifuentes* belt) of central Cuba. It is also similar and coeval with the Pen ˜alver Formation of northern Cuba. Anco´n Formation.—The Anco´n Formation reaches a maximum of 325 ft (100 m), but is commonly 65–100 ft (20 – 30 m) thick. It consists of micritic limestones

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containing planktonic foraminifera and radiolaria characterized by a reddish or greenish gray color. Truitt (1956a, b) named this unit first from the Finca Anco´n locality. Hatten (1957) also named an Anco´n Formation from the same type locality. Truitt considered the age Upper Cretaceous, whereas Hatten considered it lower Eocene. From the descriptions, they are certainly the same unit, and Truitt’s age must have been based on the abundant reworked fauna. The following fauna has been reported: Morozovella pseudobulloides, Morozovella cf. trinidadensis-precursoria, Morozovella uncinata, Morozovella cf. angulata, Morozovella cf. acuta(?), Morozovella cf. aequa, Morozovella cf. velascoensis-acuta, Planorotalites compressa, Planorotalites cf. pseudomenardii, Acarinina cf. soldadensis, Acarinina cf. brodermani, Globigerina cf. triloculinoides, and Globigerina chascanonna. The age is considered upper Paleocene–lower Eocene. In places, the upper part of the formation is characterized by reddish, marly limestones that grade into the overlying red or yellow shales of the Manacas Formation. In one locality, the lower part of the Anco´n Formation contains thinly interbedded polymictic sandstones and red shales. The red calcisiltite of the Anco´n Formation has been observed filling fractures in the underlying Cacarajı´cara Formation. The Anco´n Formation has been identified in the Naranjo, Dolores, La Serafina, and Quin ˜ones units. Manacas Formation. — The Manacas Formation consists of 1500 ft (500 m) to a few tens of feet of dominantly shales, sandstones, and limestones in the lower part and chaotic megaconglomerates and breccias (olistostromes) in the upper part. There have been differences of opinion as to the classification of these deposits. They have been described under the names of Pinar Group, Manacas, Pica Pica, and Quin ˜ ones* formations, Vieja wildflysch (also referred to as the ‘‘Big Boulder bed’’), and Canaletes chert. Hatten (1957) named the Pinar Group and divided it into the Manacas Formation, the Vieja wildflysch (Big Boulder bed), and the Canaletes chert. They were described as follows: 1) Manacas Formation — Graywackes and lithic wackes predominate in the Manacas Formation. The sequence is marine. The color of the weathered outcrop is generally light olive brown; however, some horizons are light olive to pale green. Bedding is poorly developed. The sediments are poorly sorted, ranging from 2 mm (0.08 in.) to material the size of silt. Graded bedding is com-

monly present in the formation. Much of the material seems to be made up of angular quartz and feldspar grains and fine volcanic rock fragments; all this is enclosed in a matrix of silt and clay. Common greenish gray shale horizons are found interbedded with the graywackes; some of these have been reported to be tuffaceous. Besides the above graywackes and lithic wackes, some pebbly conglomerates also exist with angular limestone clasts of a bank and near-reef type, dolomite, and rounded volcanics of olivine basalt and some intermediate porphyritic rocks. Also present are coarse grains of angular felspar and quartz. Organic material is sparse in the Manacas; the ratio of sediment to fossil remains is high. This seems to be a typical characteristic of flysch deposits of the Alpine type. On the strength of the presence of Globigerina cf. bulloides, this unit is considered lower Eocene in age. 2) Vieja Wildflysch — The Vieja Wildflysch is made up of dark greenish grey to grayish blue green highly sheared serpentinized rock. This serpentinized rock has been observed to have many varied textures. Sometimes relic crystals of enstatite(?) up to 3 mm in size can be seen. More often the serpentine is very fine grained to aphanitic. Many ‘exotic’ blocks of amphibolite, actinolite garnet schists, and hornblende-quartz rocks are enclosed by the serpentinized rock. These metamorphics are of unknown origin. Some large blocks of sharpstone conglomerate with abundant limestone clasts are frequently found. Blocks of the metamorphics as well as the conglomerate have been seen as large as 6 to 8 feet in diameter. Hatten’s Vieja wildflysch, which is intimately related to the base of the basic igneous-volcanic thrust sheet, could be a mixture of a true orogenic conglomerate and serpentine with exotics, which is common in the lower Domingo* sequence of central Cuba. 3) Canalete Cherts—The cherts are generally dark grey but weather to light grey. Bedding is generally well developed with beds uniformly near 1 cm in thickness. Between individual beds, a thin, approximately 2 to 3 mm, siliceous shale bed occurs. Radiolaria are abundant to common in the cherts and shales. No diagnostic fauna has been found in the cherts or shales. The exact stratigraphic position is therefore uncertain. From field observations, there is considerable evidence that the cherts are associated with the Pinar Group.

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Truitt (1956a, b) described a unit that he named the Quin ˜ones* Formation showing great similarity to Hatten’s Pinar Group description. It consists of basic igneous-derived conglomerate, sandstone, shale and siltstone. Dirty argillaceous red white limestone. Coarse and medium fragmental heterogeneous orbitoid limestone and limestone conglomerate. Dark brown and black thin-bedded cherts near the base. Rare basalt porphyry. Near the top are enormous tectonically jumbled blocks of actinolite schist, serpentine, diabase, spilite, tuff, and assorted flow rocks mixed with the sediments. These blocks are probably a very coarse orogenic conglomerate. Truitt considered his Quin ˜ones* Formation to be of Maastrichtian age (possibly on account of the abundant reworked fauna) and, unlike Hatten’s Manacas, included in it the chaotic megaconglomerates. Pszczo´lkowski et al. (1975) proposed the name Pica Pica Formation to replace Hatten’s Manacas and Canaletes cherts. Piotrowska (1975) describe the Pica Pica at the type locality as calcareous shales and sandstones (10.0 m), interbedding of polymict sandstones and grey micritic limestones (2.5 m), light grey and red micritic limestones (2.5 m), calcarenites with tuffaceous material (3.0 m), green tuffaceous shales (8.0 m), interbedding of polymict sandstones with shale and cherts (15.0 m), thin bedded red chert (5.0 m), polymict sandstones interbedded with breccias and shales (20.0 m). Higher up in the section chaotic rocks appear. The thickness of the Pica Pica Formation in the stratotype is 85 m. At the co-type locality it is described as yellow shales with sandstones with graywacke composition (6.0 m), a breccia with limestone and chert fragments (2.5 m), shales and graywacke sandstones (up to 30.0 m) and in the upper part, volcanic rocks (diabase and andesite) and tuffaceous rocks (30.0 m). The total thickness of the Pica Pica Formation in this section is almost 80 m. These rocks are overlain by chaotic rocks. (Note: The position of the volcanics in the Pica Pica Formation is not clear. The contact could be tectonic or they could belong to the chaotic rocks.) This unit contains abundant reworked Upper Cretaceous foraminifera and a scarce Paleogene fauna. Globorotalia cf. velascoensis has been found in the lower limestones of the formation. Therefore, the age was believed to range from the upper Paleocene through the lower Eocene. Pszczo´lkowski (1982) considered Hatten’s Manacas Formation to be the lower Manacas Member of the Pica Pica Formation and the Canalete chert to be an informal upper member of the same formation.

He did not, however, include the chaotic rocks (capas de grandes bloques) in the Pica Pica Formation. However, Pushcharovsky et al. (1988) use the name of Pica Pica (Manacas) Formation, which is defined as including olistostromes. More recently, Pszczo´lkowski (1994d) has renamed most of the Pinar Group the Manacas Formation. He subdivides it into the lower Pica Pica and upper Vieja members and considers the Canaletes chert invalid. He describes the section as follows. Pica Pica Member: — Consists of several feet to 325 ft (a few to 100 m [330 ft]) of interbedded yellow weathering clay-shales, graywacke sandstones, marly limestones, and detrital limestones. This member contains an abundant foraminifera fauna in which the following forms have been identified: Morozovella aequa, Morozovella brodermani, Morozovella cf. crassata (spinulosa), Morozovella cf. pseudobulloides, Morozovella cf. velascoensis-acuta, Morozovella cf. subbotina, ‘‘Globorotalia’’ cf. perclara, Planorotalites cf. pseudoscitula (convexa), Planorotalites compressa, Planorotalites cf. pseudomenardii, Pseudohastigerina cf. wilcoxensis, Acarinina cf. soldadensis, Globigerina cf. triloculinoides, and Chiloguembelina sp. This assemblage suggests an upper Paleocene–lower Eocene age. In addition, abundant reworked Cretaceous foraminifera exist. This member grades into the overlying Vieja Member and is in part equivalent to the Anco´n Formation. Vieja Member: —The Vieja Member consists of up to ±1300 ft (400 m) of a silty and argillaceous matrix in which are embedded pebbles to large blocks of sedimentary, metamorphic, and igneous rocks. Commonly, the lower part of the section contains limestones and chert breccias containing abundant Campanian– Maastrichtian foraminifera, with little terrigenous material. In the upper part of the member are large olistoliths (reaching several hundred meters) where serpentine dominates. Large olistoliths of interbedded basalts and cherts also exist, containing well-preserved radiolaria, very similar to the Encrucijada Formation of the Bahia Honda belt. Metamorphic blocks are also present, including eclogitic ophiolites and garnet amphibolites. Most blocks are strongly deformed (especially serpentine and pelagic limestones), indicating violent tectonic activity prior to inclusion in the deposit. The components of the breccias and conglomerates at the base of the member commonly reflect the composition of the rocks of the belt they are associated with, whereas the igneous, metamorphic, and volcanic components are commonly concentrated toward the top. No indigenous fossils have been found,

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FIGURE 92. Western Cuba, Martin Mesa area. but this unit is considered lower–middle Eocene. The upper contact is always tectonic. The presence of ‘‘Manacas chert,’’ which was somewhat puzzling in such an environment, is explained as large olistoliths of an older chert section that slid into the basin in front of the advancing thrust and has chaotically mixed within the Vieja wildflysch. It should be noted that on maps, the Pica Pica, Manacas, and Quin ˜ones* formations and the Pinar Group all have a similar distribution and, therefore, are synonymous in their practical usage. It is very important to note that Truitt’s (1956a, b), Hatten’s (1957), and the most recent of Pszczo´lkowski’s (1994d) descriptions convey the impression of the Vega* and Rosas* Formation flysch of central Cuba; they obviously depict the destruction of an advancing basic igneous-volcanic front with its detritus caught in successive, stacked, thrust sheets. On the basis of regional considerations, the Manacas Formation probably correlates with the San Martin*, Vega*, and Rosas* formations of central Cuba and the Paleocene–lower (middle?) Eocene versus lower– middle Eocene age assignments probably have more to do with the vagaries of paleontological determinations than true age differences.

As already mentioned, the Manacas Formation is present in all the belts of the Guaniguanico Range with the exception of the La Esperanza belt and the Quin ˜ ones unit of the northern Rosario belt. This is in contrast with central Cuba, where the Vega* is restricted to the Las Villas* and northern belts. Perhaps the Miguel* Formation, underlying the Domingo* sequence, is a somewhat equivalent facies of the Pica Pica Member. Northern Rosario Belt (Martin Mesa Window).— This window, containing the northern Rosario belt sediments surrounded by basic igneous and volcanics of the Bahia Honda belt, extends for 15.7 km (9.7 mi) between Mariel and Guanajay in the western Habana province (see Figure 92). The sediments within the window are tectonically very disturbed, and for this reason, the entire section has been named the Martin Mesa Group with no formal subdivisions. Martin Mesa group. — This unit is considered a tectonic complex. It consists of thin-bedded, sometimes massive, gray micritic limestones. The limestones are associated with medium-grained, brownish gray sandstones and calcareous slates. In places, the sandstones are dominant.

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The fauna consists of Nannoconus sp., Ticinella sp., Stomiosphaera sp., Pithonella sp., Rotalipora appenninica, Rotalipora cushmani, Globigerinelloides sp., and radiolaria. The age is considered Albian to Turonian, although it could extend down into the Neocomian. This unit appears to be made of Artemisa and Polier Formation components. The Martin Mesa Group (including some Upper Jurassic) has been found in several wells in northern Cuba where it has been correlated with the PlacetasCamajuani zone (Las Villas* – Cifuentes* belt) of central Cuba. According to Pszczo´lkowski (1999), the EPEP Martin Mesa-1 well was spudded in the Via Blanca Formation and encountered the Lower Cretaceous Polier Formation at 2460–5250 ft (750–1600 m), drilled across a thrust into the Campanian–Maastrichtian Cacarajicara Formation to 4105 ft (1800 m), and back into the Polier to the total depth of 9350 ft (2850 m). Northern Rosario Belt Discussion. — This belt is characterized by tholeiitic basalts interbedded with a relatively shallow-water Oxfordian sedimentary section, overlain by a complete Late Jurassic, Cretaceous, and early Paleogene section. 1) Middle and early Upper Jurassic. Nothing is known about these sediments because they do not occur in this belt. Their absence might be entirely caused by structural reasons, although the possibility exists that they were never well developed in this area or were displaced by a younger oceanic basement. 2) Middle Oxfordian– upper Oxfordian. This period of time is represented by outpourings of tholeiitic basalts, believed to be representative of a passive margin’s rifting episode. The limestones interbedded with the basalts indicate shallower than deep pelagic, reducing, and quiet water conditions. They were possibly less than 1000 ft (300 m) deep, but somewhat deeper than those in the Mogotes area. 3) Upper Oxfordian –Tithonian. A marked deepening of the basin exists in this belt accompanied by carbonate deposition, contrasting with shallower conditions of the Mogotes area. The outpouring of submarine basalts continued through the Tithonian as indicated by their presence in the La Esperanza belt. 4) Berriasian to Albian. Deep-water pelagic sedimentation continued near the carbonate compensation depth (CCD) or 3500 – 4500 m (11,482 – 14,763 ft) as indicated by the appearance of cherts and abundant radiolarians. There was an influx

of quartz turbidites of the Roble Member of the Polier Formation, probably flowing along the axis of the basin, possibly from northwest to southeast. This quartzose material, with subordinated feldspars and muscovite, probably extended as far as the Constancia* Formation of central Cuba. As will be seen later, these clastics probably correlate with those of the La Esperanza Formation in the La Esperanza belt. 5) Cenomanian to lower Maastrichtian. The Buenavista Group is a complex unit that is probably not well understood. It is still of probable deep-water origin with cherts, micritic limestones, and detrital limestones to polymictic carbonate and chert breccias. Some volcanic-derived sandstones exist. 6) Upper Maastrichtian. This time interval is represented by up to 2100 ft (700 m) of graded fragmental carbonate of the Cacarajı´cara Formation. This is an unusual detrital carbonate bed similar to and contemporaneous with the Amaro* Formation of central Cuba. 7) Upper Paleocene to lower–middle Eocene. The Manacas Formation is found capping most sections near fault zones in the same way as the Vega* Formation does in central Cuba. Its absence between the southern Rosario and the Guajaibon–Sierra Azul belts requires an explanation. It appears that the northern Rosario belt represents a post–San Cayetano–rifted basin that received an influx of quartzose clastics during the upper part of the Lower Cretaceous; this appears to be a regional Cuban phenomenon because the same sequence of events can be observed in central Cuba. During the upper Maastrichtian, it also received a large influx of turbiditic clastics from an unknown but obviously large source of shallow-water carbonates, which also appears to be of a regional nature.

La Esperanza Belt This belt extends along the north coast of Pinar del Rio for 105 km (65 mi) between Rio Blanco and Mantua, averaging less than 3 km (1.8 mi) in width over most of its length. In southwesternmost Pinar del Rio, it is repeated by folded faults. It is believed to be the western equivalent of the northern Rosario belt, possibly the lower units (see Figure 93). This belt was recognized (but not defined) by Truitt (1956a, b); he gave it the informal name of ‘‘northwestern Rosario* belt.’’ Hatten (1957) also recognized it and gave it the name ‘‘La Esperanza.’’ Both Truitt (1956a, b) and Hatten (1957) considered it as being

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FIGURE 93. Western Cuba, La Esperanza belt. related, but with a much higher percentage of Cretaceous clastics, to the sequences of the Rosario belt. Pszczo´lkowski (1976a, b, 1977, 1978) considered it a major, distinct structurofacies zone. Pszczo´lkowski (1999) does not consider it part of the Guaniguanico terrane, although he considers it equivalent to the northern Rosario belt. Most of the published descriptions are poor and incomplete, in part because of poor exposures, but mostly due to the fact that the best data are from drilling because the information supplied by EPEP is scarce and of poor quality when available; they commonly ignore the existing lithostratigraphic nomenclature. Toward the southwestern end of the belt, Pushcharovsky et al. (1988) show several serpentine and gabbro bodies associated with this unit; some are shown in fault contact with the sediments, but others are not. The largest one, the ‘‘Cabeza de Horacio window,’’ is a generally oval-shaped body, 2  5.5 km (1.2  3.4 mi) of folded gabbro and serpentine present south of Dimas. Originally, it was thought that it was surrounded by the San Cayetano Formation. However, Pushcharovsky et al. (1988) show that it is associated, and partially surrounded, by the La Esperanza Formation. It is not an intrusive as postu-

lated by Truitt (1956a, b) and Ducloz and Vaugnat (1962), but is a different tectonic unit. Pardo (1975) considered it part of the Bahia Honda belt, but it could also represents ultrabasics (El Sabalo?) associated with the La Esperanza belt. The serpentine could be related to the Vieja Member, although the Manacas Formation is not shown. In general, no good published description of the section exists. Some of the reports are conflicting, and much of the information is sketchy. Truitt (1956a, b) remarked that in the area north of the Organos* belt west of La Palma almost all the limestones of the Rosario* belt are missing and the sandstones and shales of the Cayetano Formation are overlain by the sandstones, shales, and cherts of the Lower and Upper Cretaceous. The sandstones and shales are all derived from an acid igneous source, probably from the same source, and except for the interbedded cherts in the Upper Cretaceous, are almost impossible to separate into age groups. Furthermore, the exposures of this part of the Rosario* belt are very poor, and most of the area is covered. Towards the west, towards Santa Lucia, the interbedded cherts are missing, and it is unknown whether the belt continues to the west as a solid sandstone and shale belt, representing both

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FIGURE 94. Stratigraphic section: La Esperanza belt. the Jurassic and Cretaceous time, or whether the only rocks exposed are the Cayetano Formation. Pszczo´lkowski (1978) states that there are some deposits in the La Esperanza Zone in which facies are similar to the Polier and Buenavista formations of the northern Sierra del Rosario. They probably represent the Lower and Upper Cretaceous. These deposits contain greater quantities of turbiditic sandstones than are present in many sections of the Sierra del Rosario, from which it can be inferred that there was a terrigenous influx from the northwest in Early Cretaceous.

Several wells, 10,827–18,144 ft (3300–5532 m) deep, have been drilled in this belt: EPEP Esperanza-1 and 2, EPEP San Ramon-1, EPEP Dimas-1, and EPEP Los Arroyos-1 and 2. Kuznetsov et al. (1985) and Cuba (1985a) published some incomplete information on some of these wells. Pushcharovsky et al. (1988) also provide some general information. What has been published about this belt can be summarized as follows (see Figure 94). Basic igneous rock.—In the area north of Mantua and near the Cabeza de Horacio window are several

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basic igneous bodies interbedded with the sediments of the La Esperanza Formation. They are not similar in character to El Sabalo Formation, although they are reported to be Tithonian to lowermost Cretaceous. Unfortunately, little information is available. La Esperanza Formation (Santa Lucı´a Formation). — According to Pushcharovsky et al. (1988), it consists of 3940 ft (1200 m) of interbedded sandstones, shales, and limestones of Tithonian through Neocomian age. This unit is named a formation in Pushcharovsky et al. (1988). It is informally referred to as a group by Kuznetsov et al. (1985). This section is described by Kuznetsov et al. (1985), and their description unfortunately leaves much to be desired (Spanish translation of a Russian paper). However, they divide the section into three groups of lithologies that from the bottom to the top can be named: (a) carbonate-terrigenous complex (sandyshaly-carbonaceous), (b) terrigenous complex (sandyshaly-carbonaceous), and (c) carbonate complex. In general, the section of the Esperanza Group contains several types of limestones: micrites; biomicrites; sandy, nodular, dolomitized limestones; dolomites with terrigenous material represented by calcareous sandstones; quartziferous sandstones; and thin clay beds. The Esperanza Group shows lithologic variations with the presence of carbonate rocks that contain dolomite and anhydrite in the Puerto Esperanza wells. As can be seen, this description leaves much to be desired, but suggests a possibility of a shallower-water environment of deposition with clastic influx. Unfortunately, the descriptions do not mention thicknesses, dips, type of fauna, microfacies, texture, etc., and do not mention whether the anhydrite is in beds or just fills voids and fractures (it is probably fracture filling). Furthermore, no information is present as to the nature of the dolomites. However, Kuznetsov et al. (1985) emphasize that they are similar to the Perros Formation (understood to be the Cayo Coco* Formation) of the Remedios zone. However, the presence of polymict terrigenous material in the middle of the section shows its similarity to the isochronous sections in the Sierra del Rosario (Sumidero, Polier, and Lucas formations), but these do not contain dolomites and anhydrites. They emphasize the fact that the Neocomian deposits of the La Esperanza are dissimilar from those of the Sierra de los Organos, outcropping near the Puerto Esperanza wells. According to some Cuban sources, there is a certain amount of politics involved; the La Esperanza drilling program was based on the theory that the

wells would encounter autochthonous, shallow-water sediments at depth. The reports are written emphasizing this aspect and minimizing the disturbed, deepwater turbiditic aspect. The logs of EPEP Dimas-1, EPEP San Ramon-1, and EPEP Esperanza-2 are shown in Kuznetsov et al. (1985) and in Cuba (1985a). The two sets of logs, which differ somewhat from each other, are very sketchy, but indicate that in the three wells, the section is repeated, and the Tithonian overrides the Neocomian. These logs show that the Tithonian (equivalent to the middle of the Guasasa and Artemisa formations) contains approximately 50% sandstones and shales, and that the dolomites are present in the Neocomian. In EPEP Dimas-1, a ±3300-ft (±1000-m)-thick (unknown dip) Paleogene chaotic breccia, containing gabbros and diabase (very likely the Vieja Member of the Manacas Formation), was encountered at ±13,280 ft (4050 m), below what was supposed to be the lower La Esperanza section. In the 1985 geologic map of Shien et al., 1984, logs of only a few dips are shown, and most range from 40 to 758. In Pushcharovsky et al. (1988) the surface dips shown range from 30 to 908 with the majority in the high range. Although Kuznetsov et al. (1985) considers it very important that the lower La Esperanza section is little disturbed, there is no question that it has been involved in much deformation. The La Esperanza Formation, which is considered by Pszczo´lkowski (1999) to be in part equivalent and similar to the Polier Formation, is conformable to, and possibly in part equivalent with, the overlying Santa Teresa Formation. Santa Teresa Formation. — The Santa Teresa Formation (formerly locally named the Panchita Formation) consists of 325 – 650 ft (100 – 200 m) of typical radiolarian cherts, shales, and tuffs with occasional sandstones. According to Truitt (1956a, b), the cherts seem to disappear westward, and the entire section becomes clastic. If this is the case, the Santa Teresa Formation is time equivalent to the upper part of the La Esperanza Formation, and the clastics would reach into the Upper Cretaceous. According to Pushcharovsky et al. (1988), it outcrops in the eastern part of the La Esperanza belt and has not been reported from the subsurface, although Kuznetsov et al. (1985) shows the chert symbol in the Neocomian of the EPEP Esperanza-2 well. La Esperanza Belt Discussion. — Obviously, not enough attention has been paid to this belt, and much more work needs to be done. From the sparse descriptions in a few publications, it seems to be a northwestern equivalent of the northern Rosario belt,

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with a considerable increase in acid igneous-derived clastics. It was considered as such by Truitt (1956a, b) and Hatten (1957) and, more recently, by Pszczo´lkowski (1999). The source for these clastics is debatable (Pszczo´lkowski, 1999, suggests Yucatan), but their composition suggest that they might have had the same origin as those of the San Cayetano Formation, and in the Aptian–Albian, they spread out as far east as central Cuba (Constancia* Formation). The relationship with the San Cayetano Formation of the southern Rosario belt (Pizarras del Norte subbelt) is more difficult to establish; no section has been described showing a sedimentary contact between the San Cayetano and the La Esperanza formations (the oldest reported La Esperanza is Tithonian, and the youngest San Cayetano is middle Oxfordian). The only character in common is that the clastics of both formations seem to have a similar composition. It is possible that the La Esperanza Formation stratigraphically overlies the San Cayetano and belongs to the same major thrust sheet. If this were to be the case, the fault separating the Pizarras del Norte subbelt from the La Esperanza belt would be a relatively minor imbrication. This could be supported by the absence of Manacas Formation between the La Esperanza belt and the Pizarras del Norte subbelt, although it has been found under the La Esperanza belt. However, the presence of El Sabalo-like volcanics suggests that the San Cayetano might not be present under the La Esperanza Formation, and that the La Esperanza belt, like the northern Rosario belt, forms a major thrust sheet over the southern Rosario belt and the Alturas de las Pizarras del Sur area. However, despite the presence of the Vieja Member below the La Esperanza Formation in EPEP Dimas-1, the possibility still exists that it is less displaced than the other nappes, in which case it would be related to the Gulf of Mexico, and its presence could contradict the southern origin of the San Cayetano clastics. This problem will be discussed later in this chapter.

Southern Rosario Belt In this study, the southern Rosario belt is defined as including all the exposed sediments south of the northern Rosario and La Esperanza belts and north of the window exposing the thrust units of the Mogotes area. It therefore includes the former Pizarras del Norte. Pszczo´lkowski (1977) defined the sequence of this subdivision of Truitt’s Rosario belt. The geographic distribution of the conventional southern Rosario belt was more difficult to describe, and as already mentioned and like the former Los

Organos belt, it did not fit the belt and facies-structural unit concept. To the east, the belt was bounded by major faults from the northern Rosario belt; however, the separation from the Pizarras del Norte unit of the former Los Organos belt was very questionable (see Figure 95). Like the northern Rosario belt, it has been subdivided into several structural units consisting of superimposed, thrust fault slivers (scales) repeating the section. These are, from bottom to top, 1) San Francisco–Soroa windows. These small features are believed to expose the uppermost part of the lowest sheets in the Sierra del Rosario. Only the Manacas Formation is exposed. La Zarza unit mostly surrounded the windows. 2) La Zarza unit. It is the lowest, fully exposed unit and, from east to west, is overlain by the northern Rosario belt, and the Los Tumbos, Cinco Pesos, and Taco Taco units. 3) Taco Taco unit. It overlies the La Zarza and underlies the Cinco Pesos and Caimito units. In the west, La Zarza is exposed in a window. 4) Caimito unit. It overlies the Taco Taco and underlies the Cinco Pesos, Los Bermejales, and El Mameyal units. The Caimito unit forms the axis of a broadly folded, northwest–southeast-trending stack of thrust sheets. 5) Cinco Pesos unit. It is found on the northeastern flank of the Rosario belt and overlies the three previously mentioned units. It is below the El Mameyal, Niceto Perez, and Los Tumbos units. It is also overlain by the northern Rosario belts. 6) Los Tumbos unit. It is of small extent and overlies the Cinco Pesos and La Zarza units and underlies the volcanic-sedimentary and the northern Rosario belts. 7) El Mameyal unit. East of La Palma, it overlies the Caimito and Cinco Pesos units and underlies the northern Rosario belt; it overlies the Bahia Honda area and La Esperanza belt. South and west of La Palma, it overlies the Los Bermejales (Loma Colorada), Loma del Puerto, La Paloma, and the northeastern Pizarras del Norte (La Llave, Loma del Muerto) units. It is the uppermost thrust sheet in the western part of the southern Rosario belt. 8) Niceto Perez unit. It is a small sheet that overlies the Cinco Pesos and El Mameyal units and underlies the northern Rosario belt. It is the uppermost sheet in the eastern part of the southern Rosario belt.

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FIGURE 95. Western Cuba, southern Rosario belt. 9) Los Bermejales (Loma Colorada) unit. It overlies the Mogotes area and the Caimito unit and underlies the El Mameyal unit. It appears to have a structural position equivalent to that of the Cinco Pesos unit. 10) Loma del Puerto unit. It overlies the Mogotes subbelt and underlies the El Mameyal and La Paloma units. 11) La Paloma unit. It overlies the Mogotes subbelt and the Loma del Puerto unit and underlies the Loma del Muerto and El Mameyal units. 12) Loma del Muerto unit. In most of the recent published information, including Pushcharovsky et al. (1988), this unit is named Pizarras del Norte, which is somewhat arbitrarily divided into the eastern Pizarras del Norte unit, belonging to the Los Organos belt, and the western Pizarras del Norte unit, belonging to the southern Rosario belt. The contact between these two units is poorly defined, with no clear reason given for the distinction. The division appears unfounded, and Pszczo´lkowski (1994a, b, c, d; 1999) replaces the term ‘‘Pizarras del Norte’’ by Loma del Muerto and La Paloma units belonging entirely to the southern Rosario belt. In this study, it extends

from La Palma to Mantua and Guane to the west. It approximately replaces the term Pizarras de Norte. It overlies the La Paloma unit and underlies the El Mameyal unit. It is in contact with, sometimes over or sometimes under, the La Esperanza belt. It structurally overlies the Sierra de los Organos belt. The composite exposed section, as shown in Figure 96, is as follows. San Cayetano Formation. — The San Cayetano Formation consists of a thick monotonous section where shales, sandstones, and siltstones dominate. Occasional interbeds of conglomerates and limestones (commonly at the top) exist. The color is dark gray to black when fresh, weathering to white, grayish orange, red, or grayish black. Bedding is exceptionally well developed, ranging from 1 mm (0.04 in.) laminae to 6 ft (2 m) thick. In outcrop, the formation is soft and porous; however, it is very hard and dense in the subsurface. Some authors report a slightly metamorphosed aspect. The original name was the Cayetano Formation given by DeGolyer (1918). The name was changed to San Cayetano Formation by Schuchert (1935), Imlay

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FIGURE 96. Stratigraphic section: southern Rosario belt.

(1942), and others. The present usage is San Cayetano Formation. This formation is well developed in the Pizarras del Norte subbelt, Loma del Puerto, La Paloma, Mameyal, Cinco Pesos, and Taco Taco units. It is missing or poorly represented in the La Zarza unit to the east. Pushcharovsky et al. (1988) divide the San Cayetano into a lower unit A and an upper unit B or Castellanos

Formation. According to the map legend, unit A contains sandstones, shales, and siltstones, whereas unit B is characterized by phyllitic carbonaceous schists, shale, siltstones, and limestones. The meaning of this subdivision is not entirely clear; it appears to be a lithostratigraphic subdivision, but it does not correspond to other descriptions. For instance, Pszczo´lkowski (1977) and Haczewzki (1987) report

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the sandier, and coarser, section to be near Soroa, in the eastern part of the southern Rosario belt, whereas Pushcharovsky et al. (1988) show it to be the upper unit B, which is characterized by finer materials. If it is a true time division, the criterion for the assignment is unknown. The Pizarras del Norte subbelt contains mostly outcrops of unit B; however, outcrops of unit A also exist in the northwest of the subbelt. Note that the Castellanos Formation and the units A and B scheme were never formally described. In the Mameyal, Cinco Pesos, and Taco Taco units, the San Cayetano Formation is mostly described as sandy-silty-shaly deep-water turbidite facies; a deepwater, coarse sand, fan facies is found toward the east. Although up to 1500 ft (500 m) of San Cayetano is exposed below the contact with the overlying carbonates, only some ±650 ft (±200 m) have been measured and described, which is a small percentage of the possible thickness of the entire San Cayetano Formation. The finer grained sediments are micaceous and contain occasional limestone beds. The coarse-grained facies occurs in thick beds, with pebbles up to 2 in. (5 cm), and in addition to quartz, they contain, as minor components, shale fragments, sparry carbonates (including dolomite), quartzite, chert, quartzsericite schists, granitoids, and volcanics. Plant remains are abundant. Because of the intense deformation and the monotonous nature of the section, no reliable thickness measurements exist. In the Matahambre mine, a minimum thickness of 5000 ft (1500 m) has been measured. Khudoley and Meyerhoff (1971) give estimates ranging from 10,000–16,000 ft (3000–5000 m). Pushcharovsky et al. (1988) show a thickness of more than 12,500 ft (3800 m), including 2600 ft (800 m) for the upper unit B. These estimates are compatible with the fact that the San Cayetano Formation outcrops over a large area. It should be emphasized that in the southern Rosario and Mogotes areas, the exposures of San Cayetano that underlie the carbonates are relatively thin. This could be a reflection of the original thickness of this formation. No San Cayetano has been reported in the EPEP Pinar-1 well. The Francisco or Artemisa Formation conformably overlie this unit. In this part of the belt, the following ammonites were collected from the upper part of the formation: Perisphinctes spathi, Glochiceras cf. subclausum, and Ochetoceras sp., giving an Oxfordian age; however, there is good evidence that the upper part of the San

Cayetano is equivalent to the Jagua Formation of the Mogotes area. Consequently, the San Cayetano facies becomes younger from the Mogotes toward the Rosario belt. It is not entirely clear whether the San Cayetano shown in Pushcharovsky et al. (1988) includes the western time equivalents of younger carbonate units. Francisco Formation. —The Francisco Formation consists of a maximum of 80 ft (25 m) of shales, siltstones, fine-grained limestones, and thin-bedded sandstones. Sometimes, the shales contain limestone concretions. This formation was named by Pszczo´lkowski (1976a, b). It was previously considered as the transition between San Cayetano and Artemisa formations. A few ammonites have been found as well as fish and plant remains. Globochaetes sp. has been identified. The fauna indicates a late middle Oxfordian age. This unit occupies the same position as the Jagua Formation, but is of a discontinuous nature. This unit represents a transition between the underlying San Cayetano Formation and the overlying Artemisa Formation. It is well developed over most of the belt where the Artemisa Formation is present except for parts of El Mameyal unit, where the Artemisa overlies directly the coarse-grained development of the San Cayetano. In the type area, at San Francisco, a 20-in. (50-cm) volcanic bed exists within the laminated limestones interbedded with the sandstones. It consists of basalt with albitized alkaline feldspars. This volcanism correlates with the volcanics present in the metamorphosed Jagua Formation of the Pino Solo unit and is believed related to the previously described El Sabalo Formation. Artemisa Formation.—This unit is well developed in the eastern and southern part of this belt where the La Zarza and Sumidero members are generally present. However, in addition to the two above members, the San Vicente Member of the Guasasa Formation (characteristic of the Mogotes area) intertongues with La Zarza Member. It is absent in the Pizarras del Sur and the western part of the Pizarras del Norte subbelts. San Vicente Member. —The San Vicente Member consists of up to 30 ft (10 m) of light-gray to black, massive and thick-bedded, partially dolomitized limestones with gray or black chert nodules. Micrites commonly form the base, whereas calcarenites are present in the upper part. This unit contains gastropods (Nerinea sp.), pelecypods, algal fragments, echinoid spines, and benthonic foraminifera. This assemblage indicates shallow-water

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conditions of deposition. Because of the San Vicente Member’s relation to other units, it is considered late Oxfordian to early Tithonian. La Zarza Member. — It has the same character as in the northern Rosario belt and has its best development in the La Zarza and Cinco Pesos units. Sumidero Member. — It has the same development as in the northern Rosario belt and is always present in the upper part of the Artemisa Formation. The age has been determined to be Valanginian. The Santa Teresa Formation overlies the Artemisa Formation (1) transitionally and (2) with a discontinuity (hiatus?). Buenavista group. —The term is not in use at present (Pszczo´lkowski, 1999). It occurred in the southern and central parts of the belt (lower thrust sheets), where it used to consist of the Santa Teresa, Carmita, and Moreno formations. Santa Teresa Formation. — In this belt, the Santa Teresa Formation (formerly called Sabanilla Member of the Buenavista Formation by Pszczo´lkowski, 1977, 1978) can reach 130 ft (40 m) and contains abundant Rotalipora sp., Praeglobotruncana sp., Clavihedbergella sp., Schackoina sp., and Hedbergella sp., indicating a Cenomanian to lower Turonian(?) age. However, this unit is in contact with the Artemisa Formation; therefore, here, it could range from Hauterivian to lower Turonian(?). However, it is questionable if the advent of such a characteristic chert section (observed throughout the island), which is the result of largescale geologic events (submarine volcanism), can be heterochronous. The base of the chert deposition could be an important time marker in the Aptian – Albian. It has been recognized in all the units of this belt. Carmita Formation. — This limestone-chert formation (formerly called the Limestone and Chert Member of the Buenavista Formation by Pszczo´lkowski, 1977, 1978) occurs sporadically and does not contain detrital sediments. It has been recognized in the Loma Del Puerto, Los Bermejales, La Paloma, Caimito, La Zarza, and Cinco Pesos units. Moreno Formation. —This formation is mostly absent and has been recognized only in the Loma Del Puerto and Los Bermejales units. Cacarajı´cara Formation. — This detrital unit, formerly called Breccia Member of the Buenavista Formation by Pszczo´lkowski (1977, 1978), is well represented in here, where it is 6–100 ft (2–30 m) thick and overlies unconformably the Carmita or the Santa Teresa Formation. It contains mostly limestone clasts and subordinate chert fragments.

This member is well developed in all the tectonic units with the exception of the Taco Taco unit. Anco´n Formation. — It is present in the Loma del Puerto, Los Bermejales, La Paloma, Caimito, La Zarza, and Cinco Pesos units. Manacas Formation. —This formation is present in all the tectonic units of this belt, overlying all older rocks, along the trace of the faults separating the units from each other. Drilling. — EPEP Guanahacabibes-1. The 1985 geologic map of Shien et al. (1984) shows a highly diagrammatic log of the EPEP Guanahacabibes-1 well drilled on the shores of the Golfo de las Corrientes in southwesternmost Cuba. It shows that the well penetrated Lower–Middle Jurassic shales and siltstones, under late Paleogene, at ±3345 ft (±1020 m) and slightly metamorphosed terrigenous sediments of the same age at ±4840 ft (±1475 m) until total depth at 7223 ft (2202 m). This is obviously the San Cayetano. It could represent the Cangre belt. Southern Rosario Belt Discussion. —The southern Rosario belt represents a transition between the northern Rosario belt and the Sierra de los Organos belt. 1) Middle and early Upper Jurassic. In this belt, the San Cayetano is very well developed. In the eastern part of the belt, it mostly consists of slope turbidites and coarse sandstone fan facies. In the northwestern part of the belt, shales and siltstones tend to dominate, whereas in the southern part, nearshore conditions seem to have prevailed. Fossiliferous limestones are common in the upper part of the unit, indicating shallower conditions of deposition. 2) Middle Oxfordian. It is represented by a transition between the clastics and the overlying Artemisa Formation. A good development of shale exists with ammonite-bearing limestone concretions, indicating a moderate depth of deposition with quiet conditions. In some cases, the transition is sharp. Occasional volcanics are present, possibly related to the El Sabalo Formation. 3) Upper Oxfordian–Tithonian. This is as in the northern Rosario belt. A marked deepening of the basin exists in this belt, with deeper-water carbonate deposition contrasting with shallower conditions of the Mogotes area. However, near the base of the section are tongues of the shallow-water San Vicente Member of the Guasasa Formation interbedded with the deeper water limestones of the Zarza Member of the Artemisa Formation, indicating a transition between the two belts.

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4) Berriasian to Hauterivian. Deep-water pelagic sedimentation continued near the CCD as indicated by the appearance of cherts and the abundant radiolaria. 5) Hauterivian to Albian. The deep-water sedimentation continued with the deposition of limestones, cherts, and clays of the lower Buenavista Group, and unlike the northern Rosario belt, silicate detritus is totally absent. 6) Cenomanian to lower Maastrichtian. The Buenavista Group is not as well developed in this belt as in the northern Rosario belt. It is of probable deep-water origin with cherts, micritic and detrital limestones, to polymictic carbonate and chert breccias. Some volcanic-derived sandstones exist. 7) Upper Maastrichtian. This time interval is represented by up to 100 ft (30 m) of graded fragmental carbonate of the Cacarajı´cara Formation. 8) Upper Paleocene to lower–middle Eocene. The Anco´n and the Manacas formations are found capping many sections near fault zones. The southern Rosario belt exhibits marked differences from the northern Rosario belt; it shows a very thick, possibly southern-derived, clastic section in the Lower(?) and Middle Jurassic. No evidence of extensive Upper Jurassic volcanism exists, and during the upper Oxfordian, the carbonates were deposited in shallower waters. Furthermore, no silicate clastics exist in the Early Cretaceous. The upper Maastrichtian Cacarajı´cara breccias are not as well developed as in the northern Rosario belt. Like in other parts of Pinar del Rio, the Paleocene –middle Eocene Vieja tectonic conglomerates and breccias are invariably present near fault zones.

Sierra de los Organos Belt The Sierra de los Organos belt is not a belt in the Pardo (1953) sense. It consists of a grouping of several similar carbonate-containing units and a large area where the silicoclastics of the San Cayetano alone are exposed. To better reflect the geological conditions and to avoid changing existing nomenclature, the Sierra de los Organos belt has been subdivided into the Mogotes area and the Alturas de las Pizarras del Sur area. Furthermore, the Mestanza unit of the Cangre belt, although treated as a separate belt, belongs to the Sierra de los Organos belt. Mogotes area. — The Mogotes area (the name Mogotes area has been created for this publication, but Pszczo´lkowski, 1978, 1987, described the section) is defined as a complex window, showing several stacked

thrust sheets containing the massive carbonates of the Sierra de los Organos, through the clastics of the southern Rosario belt and Alturas de las Pizarras del Sur area. It extends for 105 km (65 mi) from San Diego de los Ban ˜os to Mantua and Mendoza. Its width is commonly less than 8 km (4.9 mi) (see Figure 97). Its name is derived from the spectacular vertically faced limestone hills, named Mogotes, that form a median mountain range in the Sierra de Guaniguanico, the Sierra de los Organos. The name Mogotes Area has been created for this study, but Pszczo´lkowski (1978, 1987) described the section. Like the Rosario belt, this area has been subdivided into several units, each representing the outcrops of a nearly horizontal thrust sheet with a characteristic stratigraphic sequence. The results of the deep EPEP Pinar-1 well in the Pons Valley, in the central Mogotes area, have been recently published. A previously unknown, thick Upper Jurassic, shallow-water carbonate bank section has been reported. The previously unknown lower part of the Valle de Pons unit has also been described. This new information will be described separately in more detail. These units, the outcrops of which are shown in Figure 97, are as follows. 1) ‘‘Pinar-1’’ unit. It is the lowest unit and is only known from the deep EPEP Pinar-1 well. The unit has not been formally named, and the name ‘‘Pinar-1’’ is used only in this study. It underlies the Valle de Pons unit, and its base is unknown. 2) Valle de Pons unit. Its upper part is known from outcrops in the Pons Valley, but the lower part is only known from Pinar-1. Because of a repeat of section in the well, Pszczo´lkowski (1999) considers that two units are involved; this is possible. This unit is probably equivalent to the outcrops exposed in the Los Portales window in the southwest of the Mogotes area. The Quemado, Infierno, Vin ˜ ales, and Pizarras del Norte units overlie it. 3) Quemado unit. It outcrops only south of the town of Pons, where it overlies the Valle de Pons unit. The Infierno unit overlies it. In the southwestern Mogotes area, it is probably equivalent to the Paso Real unit that overlies Los Portales outcrops and is overlain by the Guane unit. 4) Infierno unit. It occurs mostly in the south-central part of the Mogotes area and overlies the Valle de Pons and Quemado units. To the southwest, the Guane unit is considered equivalent to the

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FIGURE 97. Western Cuba, Sierra de los Organos belt, Mogotes area.

5)

6)

7)

8)

9)

Infierno. A minor structural segment included in this unit is named the Celadas unit. Vin ˜ ales unit. This is the most extensive of the carbonate units and overlies the Infierno and the Valle de Pons units. The Anco´n, Pico Grande, and Pizarras del Norte units overlie it. Sierra la Gu¨ira unit. It occurs in the northeast of the Mogotes area. It lies over the Vin ˜ales unit. The Loma del Puerto, Los Bermejales, and Pizarras del Sur units of the southern Rosario belt overlie it. Toward the southwest, it overlies the Pizarras del Sur that is believed to be a local structural phenomenon. Pico Grande. This unit occurs between the Vin ˜ ales and Anco´n units (it is the lower part of the original Rigassi-Studer, 1963, Anco´ n unit). Toward the east, The Loma del Puerto and La Paloma units of the southern Rosario belt overlies it. Anco´n unit. It the highest carbonate unit from the Mogotes area. It is developed mostly toward the northeast, where the La Paloma unit overlies it. Limonar – Cayo las Damas window. This long and narrow window through the Pizarras del Norte sub-

belt extends from La Palma to south of Mantua. It shows mostly the underlying Manacas Formation and other outcrops of unidentified lower units. Note that the descriptions of all the stratigraphic units are based on sections exposed in the various thrust sheets forming the complex core of the Mogotes area; here, the maximum exposed San Cayetano is less than 300 ft (100 m). No proof exists that the thick, shallow-water Jurassic carbonates were originally underlain by a thick clastic section; in EPEP Pinar-1, no clastics were reported under the Valle de Pons unit. In the following, the section will be described in ascending order (see Figure 98). San Cayetano Formation. — Here, this unit consists of up to 1200 ft (400 m) of exposures of interbedded sandstones, shales, and claystones. Occasional limestones, found near the top of the section, are not more than 6 ft (2 m) thick, dark gray to black, bituminous, well bedded, recrystallized, highly fossiliferous (oyster hash), and emit a strong fetid odor when hit with a hammer. Some conglomerates are present. The base of the section is always tectonic. The San Cayetano Formation grades conformably upward into the Jagua

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FIGURE 98. Stratigraphic section: Sierra de los Organos belt, Mogotes area.

Formation, and the age of the contact varies slightly from place to place, becoming younger toward the north and east. It should be emphasized that these gradational relationships have been observed only in the units of the Mogotes area. Jagua Formation. —The Jagua Formation (named by Palmer, 1945, and described later by Pszczo´lkowski et al., 1975) consists of 100–520 ft (30–160 m) of dense, black, bituminous, medium-bedded limestones, thick beds of ‘‘oyster hash,’’ and purple-black shale with

limestone concretions in which a rich fauna of ammonites, fish, and reptile bones have been found. The Jagua Formation is characteristic of the Mogotes area and has been subdivided into the following members. Pan de Azucar Member:—The Pan de Azucar Member (originally named the Azucar Formation by Hatten, 1957, but reduced to member rank by Pszczo´lkowski, 1978) consists of 130 ft (40 m) of well-bedded, dense, bioclastic limestones (3–4 ft [1–1.5 m] thick). The

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color is dark gray to black, weathering to light gray. Some sandy limestones exist in the lower part of the member. Beds or lenses of silicified limestones contain a large number of pelecypod shells. Ostreidae and pelecypods are common, and Gryphaea mexicana is abundant. Conicospirillina basillensis is the only identified microorganism. Conicospirillina sp. has an age ranging from the Bathonian to the Kimmeridgian. Based on stratigraphic relationships, this member is assigned to the middle Oxfordian. This member is restricted to the Anco´n and Vin ˜ ales units, the Mestanza unit, and to some sections in the Pizarras del Norte and Pizarras del Sur units, lies on the San Cayetano, and is overlain by the Jagua Vieja Member of the Jagua Formation. It is the lateral equivalent of the Zacarı´as Member. Zacarı´as Member: — It consists of up to 130 ft (40 m) of argillites with fine coquina and siltstone beds. It contains abundant poorly preserved ammonite prints. In addition, less frequently, it contains Liostrea sp., Ostrea sp., Exogyra sp., and Plicatula sp. The age, based on the ammonites, is considered middle Oxfordian. This unit is restricted to the Anco´n unit, rests directly over the San Cayetano, and is overlain by the Jagua Vieja Member. It is the lateral equivalent of the Pan de Azucar Member. Jagua Vieja Member: —It consists of up to 200 ft (60 m) of laminated black shales and marly limestones with typical calcareous concretions. The calcareous concretions contain a well-preserved ammonite fauna. In this unit are the best known Cuban Jurassic fossil localities. A partial list is Paracenoceras mullerreidi, Euaspidoceras o’connelli, Ochetoceras canaliculum var. burckhardti, Ochetoceras mexicanum, Perisphinctes (Discosphinctes) subgraneri, Perisphinctes (Discosphinctes) carribeanum, Perisphinctes (Discosphinctes) antillarum, Perisphinctes (Orthosphinctes) rutteni, Perisphinctes (Arisphinctes) aguayoi, Vin ˜alesphinctes roigi, Vin ˜alesphinctes niger, and Vin ˜alesphinctes brodermani. Wierzbowski (1976) and Myczynski (1976) consider it lower Bimammatum-Bifurcatus zone or upper Oxfordian. The Jagua Vieja Member is characteristic of the Mogotes area and grades upward into the overlying Pimienta Member. It is the lateral equivalent of the Francisco Formation of the southern Rosario belt. Pimienta Member: —It consists of up to 200 ft (60 m) of interbedded dark-gray to black, well-bedded limestones and shales. The limestones are micrites, sometimes marly and medium bedded. No calcareous concretions exist in the shales.

This member contains some ammonites and has been assigned to the upper Oxfordian. The limestones contain poorly preserved planktonic foraminifera and Globochaete alpina has been identified. This member is restricted to the tectonically lessdisturbed sections of the Mogotes area and is equivalent to the contact between the Francisco and Artemisa formations of the Rosario belt. This member grades into the overlying Guasasa Formation of the Vin ˜ales Group. Guasasa Formation.—The Guasasa Formation (named by Herrera, 1961, and is, in part, synonymous with the Vin ˜ales Formation of Truitt, 1956a, b; Hatten, 1957) consists of 1000 ft (300 m) in the Anco´n unit to 2600 ft (800 m) in the Vin ˜ales unit of bedded to massive, medium-gray to black, bituminous, sometimes dolomitized limestones. In some sections, a sedimentary breccia exists at the base consisting mostly of Guasasa fragments but also containing fragments of Jagua Formation. Chert nodules are present in the lower part, and chert beds are present in the upper part. The limestones are responsible for the characteristic rugged mogotes landscape that is a mature stage of karst topography. Streams flow uninterruptedly underground through limestone hills and ridges. The age ranges from the upper Oxfordian to the early Valanginian. It has been subdivided into five members: San Vicente, El Americano, Tumbadero, Tumbitas, and Infierno. San Vicente Member: — The San Vicente Member consists of up to 1000 –2150 ft (300 –650 m) of lightgray to black, massive, and thick-bedded, partially to totally dolomitized limestones with gray or black chert nodules and lenses. In places, the limestones are bedded, oolitic, and contain abundant pellets. Micrites commonly form the base, whereas calcarenites are present in the upper part. In places, the dense micrites at the base of the formation have a peculiar pseudoporphyritic texture with euhedral anhydrite clusters of phenocrysts. In several sections, at the base, a conglomeratic limestone is made up almost entirely of Vin ˜ales and upper Jagua fragments. This conglomerate can be very thick in the south of the Mogotes area. This unit contains belemnites, gastropods (Nerinea sp.), pelecypods, algal fragments, echinoid spines, and benthonic foraminifera. Oolitic limestones containing Favreina sp. are also present in the upper part of the member. This assemblage indicates shallowwater conditions of deposition. This member has been found in all the complete sections of the Mogotes area.

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Because of the San Vicente’s relation to other members, it is considered late Oxfordian to Kimmeridgian. It is equivalent to the lower part of the La Zarza Member of the Artemisa Formation in the Rosario belts and extends as a tongue within that member in the southern Rosario belt. It also resembles and is very probably synonymous with the shallow-water carbonates of the EPEP Pinar-1 well. The upper part of this member is coeval and lithologically suggests the Hollo Colorado* and Jagu ¨ ita* formations of central Cuba. El Americano Member: —El Americano Member consists of 65 – 180 ft (20 –45 m) of dark-gray to black, granular, well-bedded limestones. Some dolomites and dolomitic limestones are present. Occasional intraformational unconformities are also present. Ammonites are present, among them Mazapilites sp. and Pseudolissoceras sp., that indicate a Tithonian age. Microfossils include Chitinoidella bermudezi, Chitinoidella cf. cubensis, Chitinoidella cf. boneti, Calpionella alpina, Calpionella elliptica, and Crassicollaria brevis. In addition, brachiopods, gastropods, pelecypods, reptile bones, and fish teeth and vertebrae are present. This fauna indicates a middle and upper Tithonian age. This member shows an increase in pelagic conditions compared to the San Vicente Member. This member also appears in the Infierno and Vin ˜ ales units. The El Americano Member is conformable with the overlying Tumbadero Member and is equivalent to the upper part of the La Zarza Member of the Artemisa Formation and the Caguaguas* Formation of central Cuba. Tumbadero Member:—It consists of 65–160 ft (20– 50 m) of well-bedded, thinly laminated, micritic limestones and calcilutites with intercalations of black chert. Rare ammonites are present, as well as a rich microfauna; Calpionella alpina, Calpionella elliptica, Crassicollaria brevis, Tintinnopsella carpathica, Tintinnosporella longa, Remaniella cadischiana, Calpionellopsis simplex, and Calpionellopsis oblonga are part of it. These indicate a Berriasian age. This member is present in all complete sections of the Guasasa Formation. It is equivalent to the lower Sumidero Member of the Artemisa Formation and is also similar and equivalent to the Capitolio* Formation in central Cuba. Tumbitas Member: —It consists of 130 – 260 ft (40 –80 m) of light-gray, dense, micritic limestones with some thin beds of darker color. The beds are commonly mottled because of bioturbation. A rich microfauna is present, with Calpionella alpina, Calpionella elliptica, Tintinosporella carpathica,

Tintinosporella longa, Romaniella cadischiana, Romaniella dadayi, Calpionellopsis simplex, Calpionellopsis oblonga, Calpionellopsis darderi, Globochaetes alpina, and Nannoconus sp., among others. The age is considered to be late Berriasian to early Valanginian. This member has been also recognized in the Infierno and Vin ˜ ales units. This unit is considered equivalent to the upper Sumidero Member of the Artemisa Formation and to the upper Capitolio* and Ronda* formations of central Cuba, although aptychi are not common. It is conformable with the overlying Infierno Member. The upper Guasasa Formation used to be called Infierno Member (very likely synonymous with Truitt’s Guajanı´ Formation; it is included in Hatten’s [1957] upper Vin ˜ales), consisting of 0–160 ft (0–50 m) of wellbedded, light-gray, micritic limestones and black cherts. This member was present in the Infierno and Vin ˜ales units. However, Pszczo´lkowski (1999) eliminated the term and considers it part of the lower Pons Formation, equivalent to the Santa Teresa Formation. It also resembles and is part equivalent to the Ramblazo* and Calabazar* formations of central Cuba. The upper boundary of the Guasasa Formation is erosional and overlain by the Paleocene breccias of the Anco´n Formation. Pons Formation. —The Pons Formation consists of 650 ft (200 m) of light-gray to almost black, wellbedded, micritic limestones interbedded with thin, black chert beds, nodules, and lenses. Some thin yellowish brown shales are present. In the lower part, thick-bedded, light-gray mottled limestones are more common. The microfauna of the lower part consists of Globigerina cretacea, Planomalina buxtorfi, Praeglobotruncana sp., Ticinella sp., Globotruncana lapparenti, Rotalipora cf. appenninica, Thalmalinella cf. greenhornensis, Nannoconus truitti, N. wassalli, Nannoconus bucheri, and Nannoconus elongata. Hatten (1957) considered this unit to extend from the Albian through the Campanian. More recently, the range has been extended from the Hauterivian(?) to the Turonian. Hatten (1957) described and named two superimposed stratigraphic units that he called the Pons and Pen ˜as formations. Piotrowska (1975) considered both of them lithologically similar and included the Pen ˜as into the Pons Formation. The present thinking is that both formations should be recognized (Pszczo´lkowski, 1999). The Pons Formation outcrops are restricted to the Pons Valley, in the central part of the Sierra de los

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Organos, in windows exposing the Pons and Pica Pica units. These are the lowermost thrust sheets observable on the surface. Consequently, the base of the Pons Formation has not been observed in the type section. This unit is lithologically similar and equivalent, and could well be synonymous, with the Infierno Member of the Guasasa Formation and the Carmita Formation of the Buenavista Group. It also appears to be equivalent to the Aptian – Albian part of the deep-water carbonate section drilled in EPEP Pinar-1 (spudded in the Pons Valley) between 1640 and 2870 ft (500 and 875 m), although in this section, cherts are not mentioned. The Pons Formation is equivalent to the Ramblazo* and certainly part of the Malpaez* Group (Calabazar* and Mata* formations) in central Cuba. Pen ˜ as Formation. — It is similar to the Pons Formation, but the beds are thinner; the color of the limestone tends to be darker, with white calcite veins; and the chert beds are more abundant. The limestones give off strong petroleum odor when freshly broken. In the type section, it is 250 ft (80 m) thick. It contains Globigerina cf. cretacea, Rugoglobigerina sp., Rugotruncana calcarata, and Globotruncana lapparenti sl. The age is considered Campanian – Maastrichtian. Recent paleontological studies indicate the presence of a hiatus in the Sierra de los Organos comprising the late Turonian and the Santonian. Moncada Formation. — The Moncada Formation (described and named by Tada et al., 2003) consists of 6 ft (2 m) of a calcareous sandstone complex. It contains a mixed faunal assemblage from Aptian to Maastrichtian. It is considered to represent the sediments produced by the Chicxulub meteorite impact at the K/T boundary. Grains of impacted quartz are abundant, and the upper calcareous claystone bed is rich in iridium. This unit correlates with the Cacarajicara. Anco´n Formation. — The Anco´n Formation consists of 0 – 160 ft (0 – 50 m) of well-bedded, pink, green, yellowish brown, and red, laminated, marly, micritic limestones. The limestones are highly fossiliferous. Interbeds of breccias and conglomerates exist with subangular clasts up to several centimeters consisting of oolitic limestones, calpionellid-bearing limestones, cherts and dolomites. Occasionally, thin beds of lightgreen volcanic sand grains occur in the calcareous sandstones. The Anco´n Formation rests disconformably on the Pen ˜as and Pons formations. No angular unconformity exists, but an irregular erosion surface can be observed. In the Mogotes area, it has been divided into three members: La Gu ¨ ira, ‘‘Marly Micritic

Limestone,’’ and La Legua. This formation has been found in all the units of the Mogotes area. La Guira Member: —It consists of up to 160 ft (50 m) of a breccia with fragments up to 16 in. (40 cm), derived mainly from the limestones of the various members of the Guasasa Formation. Chert is also present. The matrix is commonly invisible. Marly limestones can be observed at the top of the breccia and are also its lateral equivalent. The breccia contains reworked fossils of all the underlying units. This member is found in the Sierra de la Gu ¨ira, Anco´n, Vin ˜ ales, Infierno, Valle de Pons and La Legua units. Marly Micritic Limestone Member:— As indicated by its name, it consists almost entirely of the abovedescribed limestones. This unit is richly fossiliferous, and the following foraminifera have been identified: Globorotalia (Morozovella) velascoensis (very abundant), Globorotalia (Morozovella) wilcoxensis, Globorotalia (Morozovella) brodermani, Globorotalia (Morozovella) elongata, Globorotalia (Morozovella) occlusa, Globorotalia (Morozovella) cf. aequa, Globorotalia (Morozovella) cf. acuta, Planorotalia (Planorotalites) pseudomenardii, Acarinina cf. soldadoensis, and Globigerina velascoensis. This assemblage indicates the upper Paleocene. La Legua Member. — La Legua Member consists of a breccia similar to the La Gu ¨ ira Member, but commonly occurs at the top of the formation. It can reach 80 ft (25 m) in thickness, and the blocks are 16 ft (5 m) in length. Fewer chert fragments are present. The Anco´n Formation has obviously been deposited in deep water as indicated by the rich pelagic fauna in the micritic limestones and the interbedded coarse breccias without visible matrix, suggesting the Sagua* Formation of central Cuba. In this case, the talus origin of the breccia has certainly to be ruled out because no shallow banks were present to supply the coarse detritus. The breccias must have been originated from an uplift of the previously deposited carbonates and cherts. The Anco´n Formation is younger than the Cacarajı´cara and older than the Sagua* Formation. The Manacas Formation overlies the Anco´n with strong unconformity. Manacas Formation. — It is well developed in the Mogotes area where it was originally described; it is found at the top of every structural unit. Pinar-1. — Two of the units of the Mogotes area deserve special description because the complete sections have been seen only through drilling of EPEP Pinar-1, a deep, parametric well drilled to 17,056 ft (5200 m) in the Pons Valley, 4 km (2.5 mi) south of

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FIGURE 99. Stratigraphic section: Sierra de los Organos belt, Pinar-1 unit.

the town of Pons (see Figure 97). This well, located in the middle of the complex Pica Pica and other outcrops belonging to the Valle de Pons unit of the Mogotes area, encountered a possibly autochthonous, shallow-water carbonate section of Jurassic age. The base has not been observed. Lopez Rivera et al. (1987) and Pszczo´lkowski (1994a, b, c, d; 1999) described the section, which is partially repeated three times, and the lithostratigraphic units have not been formally named. A recurring problem in Cuba is that, accord-

ing to the Soviet-era stratigraphic philosophy (strongly biostratigraphic), the geologists working for EPEP emphasize the fossil content and the age of the section penetrated by the drill and only summarily describe the lithology and, contrary to the geologists working for the Academy of Science, seldom attempted to classify them within the established lithostratigraphic framework (see Figure 99). Pinar-1 Unit: —The Pinar-1 unit is present from 7872 to 17,056 ft (2400 to 5200 m). Part of the section

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is repeated by a fault at ±10,500 ft (±3200 m). This unit is entirely subsurface and is not in the literature; it has been named solely for this study. Guasasa Formation(?): Pinar-1 Shallow-Water Carbonate:— It consists of 4920 ft (1500 m) of massive limestones. Lower section:—The lower section consists of 2296 ft (700 m) of fine-grained limestones with variable amounts of coproliths and organic remains. The color is dark gray to black, and gypsum and anhydrite commonly fill fractures and vugs. The anhydrite increases toward the lower part of the hole. The fauna consists of Favreina salavenses, Didemnoides moreti, Globochaete alpina, and Cadosina sp., indicating an Upper Jurassic age. Upper section: —The upper section consists of 2624 ft (800 m) of fine-grained limestones, with variable amount of clay and varying degrees of dolomitization. Abundant coral and pelecypod fragments, echinoderm spines, coproliths, molds of ostracods, brachiopods, and benthonic foraminifera are present. Questionable recrystallized radiolaria are also present. The following forms have been identified: Saccocoma sp., Cadosina sp., Favreina salavensis, and miliolids, indicating an Upper Jurassic age. This shallow-water carbonate unit has similarities (although much thicker) and is partly coeval with the San Vicente Member of the lower Guasasa Formation of the Mogotes area and also suggests the Hollo Colorado* Formation of the Las Villas* belt in central Cuba. Although gypsum and anhydrite are reported, there is no mention of evaporite beds. Note that the crustal measurements described in Chapter 6 of this publication indicate that the top of the basement in Pinar del Rio is at ±5 km (±3.1 mi). This is close to the total depth of EPEP Pinar-1, and yet, there is no indication of the presence of terrigenous clastics. Guasasa Formation(?): Pinar-1 Deep-Water Carbonate:—It consists of 3575 ft (1090 m) of a tectonically repeated 1800-ft (550-m) section of fine bioclastic, massive, light-gray to black limestone. The section can be subdivided from bottom to top into three biozones as follows. 1) Upper Jurassic (Tithonian) containing Saccocoma sp., Aptychus sp., Cadosina sp., and molds of radiolaria. 2) Neocomian containing Cadosina sp., Nannoconus steinmanni, Nummulites cf. bermudezi, Tintinosporella longa, Calpionellopsis simplex, Remaniella sp.(?), Globochaete alpina, and Calpionella sp. Radiolaria and embryonic ammonites are also present.

3) Aptian – Albian containing Nannoconus truitti, Nannoconus elongatus, Nannoconus spp., Hedbergella cf. infracretacea, Hedbergella spp., Clavihedbergella sp., Cadosina sp., Globigerinelloides sp., Ticinella sp., Preaglobotruncana sp.(?), Tintinopsella sp.(?), and Heteroelicidae. The middle zone is argillaceous with clay beds, whereas the lower zone has pronounced light-gray and black banding. In general, the dips are low (58 or less; only one core shows 408 dips). This section is correlative with the upper Guasasa Formation of the Mogotes area and the upper Artemisa – lower Buenavista Group of the southern Rosario belt. It also suggests the Caguaguas*, Capitolio*, and Ramblazo* formations of central Cuba, although no chert is reported. Manacas Formation: — In the Pinar-1 unit, this formation consists of 689 ft (210 m) of breccia, with an argillaceous matrix containing fragments of several types of limestones, chert, silty shales, quartz sandstones, diabase, and tuffs. The fragments contain a fauna consisting of Orbitocyclina sp., Pseudorbitoides sp., Sulcoperculina globosa, Ctenorbitoides cardwelli, Globotruncana sp., Globigerinelloides sp., Stomiosphaera sp., Sulcorbitoides pardoi, and rudist fragments, echinoid spines, and mollusks. The age of the components is as young as Maastrichtian, although the Manacas Formation is considered of Paleocene to middle Eocene age. Valle de Pons Unit: Lower Section. — The lower section of the Valle de Pons unit is present from the surface to 7872 ft (2400 m). In Pinar-1, the interval from the surface to 7872 ft (2400 m) is found a sequence of Lower Cretaceous deep-water and Upper Jurassic shallow-water carbonates below the Manacas Formation. This section represents the lower part of the Valle de Pons unit, which has never been observed on the surface. Parts of the section are missing, and intense fracture zones are present. The drilled interval seems to be part of a complex thrust sheet. Guasasa Formation(?): Pinar-1 Shallow-Water Carbonate: — This section is present from 2870 to 7872 ft (875 to 2400 m). The thickness of 5000 ft (1525 m) is believed to be in part caused by a repeat by a reverse fault. The dips are not mentioned, but the contact with the overlying deep-water carbonates is believed to be faulted. Guasasa Formation(?): Pinar-1 Deep-Water Carbonate:—The Pinar-1 deep-water carbonate is present from less than 1640 to 2870 ft (500 to 875 m). This section is believed to be part of a recumbent fold

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because the top and bottom of the section contains Aptian–Albian faunas, whereas the center of the interval is of Neocomian age. This inversion could be caused by faulting. Manacas Formation: —This unit occurs from the surface to less than 1640 ft (500 m). It is described as a volcanic sequence pertaining to an olistolith in the Vieja Formation or, not very likely, as the eugeosynclinal overthrust. The lower contact is questionable because the well was spudded in the Manacas Formation, and no data were taken until 1640 ft (500 m). Mogotes area discussion. — The Mogotes area represents a series of thrusts, or nappes, supposedly directed toward the north. The possibility exists that the Pinar-1 unit is very nearly in place and is resting directly over basement. The predeformation succession of facies is not as easy to visualize as in central Cuba. The most important aspects of the present facies distribution are as follows. 1) Middle Jurassic to middle Oxfordian. The continental margin clastics of this age are not well developed in this belt. Although the base of the Pinar-1 unit was not reached, clastics were not reported between the base of the Valle de Pons unit and the top of the Pinar-1 unit. The only rocks of this age observed in the higher structural units are middle Oxfordian and characterized by shallowwater, anoxic sediments as indicated by abundant oyster-hash sulfurous limestones, suggesting \swamp conditions. These shallow-water conditions appear to be somewhat younger in the Rosario belt than in the Mogotes area. 2) Middle Oxfordian. The Jagua Formation and the Zacarı´as and Jagua Vieja members indicate nearshore conditions of deposition in an anoxic environment probably less than 350 ft (100 m) deep. The large, laminated, early diagenetic concretions and the abundant undamaged ammonite shells indicate quiet conditions not affected by waves and currents. The rate of sedimentation must have been low, and the presence of wood remains indicates some connection to a delta and/or swamps. 3) Upper Oxfordian. The equivalent of the base of the Artemisa Formation indicate a decrease in terrigenous material, an increase in planktonic microorganisms, and a deeper water carbonate platform environment. 4) Kimmeridgian and early Tithonian. The sedimentation was of shallow-water bank carbonates; oolites, oncolites, biomicrites, coprolitic micrites, etc. Favreina spp. is a common fossil. These de-

5)

6)

7)

8)

posits appear to be the thickest in the Pinar-1 unit, reaching more than 4920 ft (1500 m) in the lower thrust sheet. This gives a rate of sedimentation (after compaction) of ±410 ft/Ma (±125 m/Ma), which is quite comparable with that of sediments of the same age in the Las Villas* belt. On the outcrop, the thickness reaches 2132 ft (650 m). It should be mentioned that the San Cayetano facies was not reached in EPEP Pinar-1, although according to seismic studies, the total depth is supposed to be near the top of the basement. The next higher thrust sheet, the Valle de Pons unit, still does not show clastics at the base. Only the uppermost outcropping sheets, Quemado and higher, shows the transition from San Cayetano, through Jagua, into the San Vicente Member of the Guasasa Formation. Middle Tithonian. There was regional subsidence and a marked deepening of the sea. The deeper water, pelagic facies of El Americano Member, with abundant tintinids and radiolaria, replaced the shallow waters of the San Vicente Member. The sedimentation rate (after compaction) dropped to ±33 ft/Ma (±10 m/Ma). The depth was probably close to the aragonite compensation depth. These deposits, and the depth change they represent, are very similar and might be coeval with the change from the shallow-water, oolitic Jaguita* to those of the Caguaguas* Formation of central Cuba. Upper Tithonian through Valanginian. Deep-water conditions continue throughout the Mogotes area, with the deposition of pelagic limestones containing tintinids, nannoconids, and radiolaria of the Tumbadero and Tumbitas members of the Guasasa Formation. These units are coeval and lithologically very similar to the Sumidero Member of the Artemisa Formation and to the Capitolio* and Ronda* formations of central Cuba. Hauterivian and Barremian. Deep-water conditions continue with added siliceous sediments of the Tumbitas Member and the lower part of the Pons Formation. These suggest that the water depth was near the carbonate compensation depth. These sediments correlate with the lower part of the Santa Teresa Formation and the Polier Formation. However, no traces of clastics exist, which would indicate that the Polier Formation clastics could not have come through the Mogotes area. Aptian through Albian. This is represented by the Pons Formation and its possible equivalent in a

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different structural unit, the Santa Teresa Formation. The deposition of chert continues, indicating a continuing deep-water environment, possibly near the carbonate compensation depth (CCD). 9) Upper Cretaceous. The Pons Formation continues into the Turonian; however, the Pen ˜ as Formation of Campanian–Maastrichtian age has similar facies. It is separated from the Pons by a hiatus. The total thickness of the Pons and Pen ˜as is not more than 650 ft (200 m), which could represent the entire Cretaceous, or a sedimentation rate (after compaction) of ±8.8 ft/Ma (±2.7 m/Ma). This is very low compared to other deep-water sedimentation rates and indicates that part of the section is missing. It should be noted that the Maastrichtian carbonate detritus of the Cacarajı´cara Formation have not been reported in this belt, but is replaced by the calcarenites of the Moncada Formation. 10) Paleocene. The Anco´n Formation marks an important break in the section; an influx of breccias and polymict detritus exists in a deep-water environment characterized by marls and cherts. The rate of sedimentation is still low, and the type of sediments indicates some early deformation and subaerial erosion of carbonates as well as a basic igneous-volcanic terrane. 11) Lower –middle Eocene. This time span witnesses the continuation of the influx of polymict detritus (Pica Pica Member) of the Manacas Formation and subsequent chaotic rocks of the Vieja Member. This is an orogenic conglomerate containing not only large-size components of the nearby carbonates, but also of volcanics, gabbros, serpentine, schists, etc., in a graywacke matrix. It is very significant that this breccia is found mostly in fault zones above the carbonate section in the Mogotes area as well as in the Rosario belts. It has never been found in stratigraphic contact with the underlying San Cayetano Formation of the Pizarras del Norte unit and Alturas de las Pizarras del Sur area; the nearly continuous band of Manacas outcrops in contact with the San Cayetano shown in the Pushcharovsky et al. (1988) is a window through the Pizarras del Norte unit. This indicates that the unit was deposited as the youngest layer in the basin, possibly as a large-scale olistostrome, prior to the faulting, but after some erosion or collapse of the basic igneous-volcanic terrane to the south had occurred. Whether it was synchronous over the

entire basin or was deposited as a wave in front of an advancing thrust sheet is not known. At any rate, it must have been deposited over a short period of time. Alturas de Las Pizarras del Sur area. —This area is to the south of, and tectonically overlies, the carbonate units of the Mogotes area. To the south, the Pinar fault and the Cangre belt form its southern limit (see Figure 100). It is the southern equivalent of the Pizarras del Norte unit. The section consists entirely of the San Cayetano clastics because the contact with the overlying carbonates has only been observed in the metamorphosed Cangre belt. This group of rocks should not be part of the Mogotes area and, in view of its following fairly well the definition of belt or facies-structural zone ( because it is limited by faults and has a characteristic stratigraphy), should be a belt. The section is shown in Figure 101. San Cayetano Formation. —It consists of the same thick monotonous section of shales, sandstones, and siltstones as present in the southern Rosario belt, except that coarser clastics predominate. The shales are phyllitic with common sericite. Rare carbonaceous zones with carbonized wood particles are present. The sandstones are poorly sorted with two generations of quartz. One is rounded, whereas the other is angular. More than half of the matrix consists of silt or finer particles. The cement is ferruginousargillaceous. Feldspars are rare, and muscovite is common. The sandstones weather to a soft friable sand. The coarse sandstones and conglomerates have fragments up to 2 in. (5 cm) in diameter. In addition to quartz, they contain, as minor components, shale fragments, sparry carbonates (including dolomite), quartzite, chert, mica schists, granitoids, and volcanics. The sedimentary features include cross-bedding, graded-bedding, slump folds, load-casts, and cut-andfill structures. As already mentioned, Pushcharovsky et al. (1988) subdivide the formation into units A and B informal members and shows that most of the outcrops in the Alturas de las Pizarras del Sur area belong to the sandier unit A. A normal stratigraphic contact between the San Cayetano and the overlying Jagua (or Francisco) has not been reported in the Alturas de las Pizarras del Sur area. Pushcharovsky et al. (1988) show such a contact only in the easternmost part of the Pizarras del Sur unit, near San Diego de los Ban ˜ os. Pszczo´lkowski (1999) shows it to be a window exposing the

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FIGURE 100. Western Cuba, Sierra de los Organos, Pizzaras del Sur area.

Mogotes area Vin ˜ales unit. The base has never been observed. The San Cayetano Formation is very poorly fossiliferous in this area. Very few fossil localities are known, and these contain only pelecypods and plant remains. One fossil locality yielded Cuspidaria sp., Modiolus sp., and Trigonia sp., nondiagnostic of either Jurassic or Cretaceous. However, the trigonias have affinities to species from the Middle to Late Jurassic. Another locality had an assemblage of Eocallista spp., Vaugonia spp., Gervillia sp., and Neocrassina spp. of undetermined age. As already mentioned, ammonites were collected from the upper part of the formation in the southern Rosario belt, Perisphinctes spathi, Glochiceras cf. subclausum, and Ochetoceras sp., giving an Oxfordian age. The transitional contact with the Jagua Formation, observed in the Mogotes area and the Cangre belt, has been well dated at upper middle Oxfordian to lower upper Oxfordian, therefore fixing the age of the top of the San Cayetano at middle Oxfordian. However, no reliable evidence exists for the age of the base of the formation; guesses range from the Middle to the Lower Jurassic (Triassic has even been proposed).

Of great importance is the origin of the San Cayetano clastics. Haczewski (1976, 1987) published the result of a sedimentological reconnaissance of the San Cayetano. He recognized nine facies characteristic of deltaic sedimentation on a continental margin. Most of the fluviatile, delta-plain, and nearshore facies were found to the southwest in the Alturas de las Pizarras del Sur area and western Pizarras del Norte unit; the turbidite deposits are characteristic of the eastern southern Rosario belt (eastern Pizarras del Norte unit, El Mameyal unit), and the slope deposits were located to the northeast of the Mogotes area (Anco´n unit). This pattern suggests that the deep water is to the east-northeast of the Sierra de Guaniguanico. What it was before deformation is another story. In addition, measurements on ripple marks indicate that the direction of transport was in a general northeasterly direction, indicating a southwestern source. The exact meaning of these observations is not clear until the relative motions of the Mogotes, Pizarras del Sur areas, and Rosario belt are resolved. At any rate, the San Cayetano exposures in the Pizarras del Norte show a higher percentage of fine-grained clastics and clay than the Pizarras del Sur. Assuming that both

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FIGURE 101. Stratigraphic section: Sierra de los Organos belt, Pizzaras del Sur area.

sections were continuous, approximately of the same age, and that the Pizarras del Norte were deposited south of the Pizarras del Sur, this supports the argument of the northern origin of the clastic detritus. If the thickness of the detritus exposed under the different thrust sheets has any bearing on the original thickness of sediments (the de´collement might have been at the base of the clastics), then the San Cayetano would have been well developed only in the Pizarras del Sur and southern Rosario belts. The Mo-

gotes area and the northern Rosario belt would have been originally underlain by thin or no San Cayetano. Therefore, regardless of the direction of thrusting, no autochthonous Jurassic clastics should be expected in the present northern half of Pinar del Rio. Alturas de Las Pizarras del Sur area discussion. — The San Cayetano Formation in this area represents deposition in a relatively deep basin receiving sediment from a major continental source such as an important river delta. The depth of deposition

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FIGURE 102. Western Cuba, Cangre belt. is difficult to estimate because of the lack of wellpreserved faunas (which is common in turbid sediments). The sedimentological studies indicate nearshore, shallow-water deposits as well as deeper water turbidites and fans. These suggest a southern source of sediments; however, because of the absence of recognizable markers in the section and the structural dislocations, it is impossible to reconstruct the three-dimensional geometry of the deposits. In general, field mapping indicates that the lower part of the section contains a dominance of coarser sediments, whereas the upper part, with few exceptions, is characterized by a much higher percentage of shales. As already mentioned, the possibility exists that the Alturas de las Pizarras del Sur area is the northern and western equivalent of the southern Rosario belt.

Pszczo´lkowski (1976a, b) to identify a structural unit in the northern Rosario belt. It is present along the northern upthrown side of the Pinar fault and extends for some 72 km (44 mi). It has been subdivided into two units:

Cangre Belt

Although Piotrowski (1977) reports the section as overturned, Pszczo´lkowski (1985) shows the Mestanza unit to be right-side up, with the Pino Solo unit riding over rocks ranging from the Guasasa to the Manacas Formation. The total exposed thickness of the Pino Solo thrust sheet is 1990 ft (610 m) and is considered the highest thrust fault of the Cangre belt. The lower

This narrow belt is called Cangre unit in Pushcharovsky et al. (1988) (and other publications) (see Figure 102). This unit is referred to as the Cangre structurofacies unit in the Pushcharovsky et al. (1988) and other publications. This name will not be used in this study because it has been previously used by

1) Mestanza unit. It is a thin, south-dipping, thrust sliver wedged between the Alturas de las Pizarras del Sur area and the Pino Solo unit. It is characterized by a thin Jurassic carbonate section and by some degree of metamorphism. 2) Pino Solo unit. It extends for 70 km (43 mi) along the Pinar fault and represents the uppermost and most metamorphosed thrust sheet of the Alturas de las Pizarras del Sur area. North of it is a klippe of the same subunit named the Cerro de las Cabras unit.

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FIGURE 103. Stratigraphic section: Cangre belt.

Mestanza unit exposes some ±650 ft (±200 m) of section (see Figure 103). The section is as follows. Mestanza unit. — San Cayetano Formation. —In this unit, only the uppermost outcrops of this formation are present. A gabbro is present at the top of the formation. Jagua Formation.— The Jagua Formation consists of 100 (30 m) of a section very similar to the nonmetamorphosed section in the Mogotes area. It contains limestone concretions with middle Oxfordian

ammonites. The volcanics consist of a gray chloritic tuff and, higher in the section, several horizons of a very altered, greenish gray, volcanic rock, which is believed to have been originally a basalt of intermediate composition (Piotrowski, 1987). This unit grades conformably into the Guasasa Formation. Guasasa Formation. —The base of this massively bedded unit, with the exception of some recrystallization, is identical with the unmetamorphosed section

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of the Mogotes area. In the Piotrowski (1977) description of the section, it is not clear if this lithology belongs to the Pino Solo or Mestanza units. According to Pszczo´lkowski (1985), more than 230 ft (100 m) of Guasasa normally overlies the Jagua Formation in the Mestanza unit. It is represented by the San Vicente Member, which is unconformably overlain by the Guı¨ra Member of the Anco´n Formation. Anco´n Formation. — In this unit, this formation consists of some 15 ft (5 m) of metamorphosed breccias of the Guı¨ra Member and the red and gray recrystallized, schistose limestone with a breccia at the top. The Manacas Formation conformably overlies it. Manacas Formation. —The unit consists of some 25 ft (8 m) of red, green, and gray schists of the Pica Pica Member of this formation. This is the youngest unit present under the Pino Solo unit basal thrust sheet and represents the youngest metamorphism in western Cuba, lower – middle Eocene. Pino Solo Unit. — Arroyo Cangre Formation.—This formation is 1836 ft (560 m) of a metamorphosed, dominantly clastic sequence described by Piotrowski (1977) from south to north as follows: 59 ft (18 m): Polymictic meta-sandstones, quartzchlorite schists, and marbles. 62 ft (19 m): Recrystallized limestones, banded, with oriented texture caused by the presence of muscovite and sericite; quartz lenses. 43 ft (13 m): Quartz-chlorite-muscovite schists interbedded with meta-sandstones. 30 ft (9 m): Fine-grained amphibolite with lepidoblastic structure and oriented texture. 33 ft (10 m): Metasiltstones, metamorphosed limestone, and chloritic schists. 20 ft (6 m): Cataclastic gabbro. 590 ft (180 m): Interbedding of fine to medium grained quartz meta-sandstones, containing subordinate amounts of volcanic rocks, plagioclase, mica, and epidote, and quartz-muscovite schists. 836 ft (255 m): Interbedding of muscovite-chloritequartz crystalline schists with sericite and beds of metasandstones. Although this section is reported to be continuous and overlain by the Jagua Formation, the contact between the two units is always reported as strongly tectonized. The thickness of 1436 ft (435 m) for the San Cayetano equivalent appears low compared to its thickness in the Alturas de las Pizarras del Sur area.

This unit, which is very similar to and the equivalent of the San Cayetano Formation, was given a different name on account of the marbles near the top, the metamorphism, and the presence of volcanics. The volcanics in the southern 246 ft (75 m) of the section are tuffs consisting of a cryptocrystalline mass in which quartz, feldspars, chlorite, and sericite can be recognized. This mass is saturated with epidote. Above the tuffs are cataclastic, medium-grained, crystalline basalts and a porphyroclastic gabbrolike rock. In the northern 164 ft (50 m) of the Arroyo Cangre Formation, near the contact with the Jagua Formation (probably belonging to the Mestanza unit), are thin lamprophyres (monchiquite) interbedded with the carbonate rock. It is worth mentioning that the lower Mestanza thrust sheet is less metamorphosed than the upper Pino Solo sheet, which is reminiscent of the situation in the Escambray and other metamorphic massifs. Cangre Belt Discussion. — In the metamorphic Cangre belt, volcanics are present in the Jagua Formation; they are equivalent in age to the El Sabalo Formation and to the basalts found in the Francisco Formation. These are the oldest volcanics associated with the Mesozoic sediments of Pinar del Rio and are therefore not related to the thermal activity responsible for the lower–middle Eocene regional metamorphism of the metamorphosed units. Also of great interest is the fact that the regional metamorphism is dated as middle Eocene or younger and appears to be equivalent or even predate the thrusting; remnants of the metamorphosed Arroyo Cangre are found along the southern border of the Pizarras del Norte unit. The reason for this metamorphism is not clear; it could be related to the ophiolite obduction.

Guaniguanico Mountains Sediments Discussion As mentioned, unlike central Cuba, the paleoconfiguration of the platform to deep basin province will depend heavily on the structural interpretation (and vice versa); it is difficult to set an a-priori facies distribution. An attempt will be made to reconstruct some likely models of what this sedimentary province might have been like prior to the deformation. It is not the purpose of this book to revise the present stratigraphic nomenclature of Cuba; however, it is pertinent to remark that, until now, the terminology tended to obscure the important aspects of Pinar del Rio stratigraphy. Although E. DeGolyer’s original name of Vin ˜ ales limestone was poorly defined and much misused, the way it was used by Truitt (1956a, b) and Hatten (1957) described well the

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shallow-water, massive, commonly very thick, mogoteforming limestones of Upper Jurassic age. It is a major stratigraphic unit of the area, which, in today’s nomenclature, is lost as the San Vicente Member of the Guasasa Formation of the Vin ˜ales Group. The same is true for Lewis’ Artemisa Formation, also poorly described, but given a precise meaning by Truitt (1956a, b) and Hatten (1957), who called it the Rosario Formation. It was originally the thin-bedded, argillaceous, deep-water equivalent of the Vin ˜ales Formation. Until recently, it was the La Zarza Member of the Artemisa Formation of the Vin ˜ ales Group. However, some very distinctive and approximately coeval lithologic assemblages, all characterized by the presence of thin-bedded chert with variable amounts of thin-bedded limestones and clays, are given names with the rank of formation or members within or outside higher hierarchical units. For instance, until recently, the Pons Formation of the Vin ˜ ales Group was similar to (1) the Infierno Member of the Guasasa Formation of the Vin ˜ ales Group, (2) the Sumidero Member of the Artemisa Formation of the Vin ˜ ales Group, (3) the Sabanilla Member of the Buenavista Formation, and (4) the Sierra Azul Formation. Recently, Pszczo´lkowski (1994a, b, c, d; 1999) improved the situation by not using the Vin ˜ ales Group, the Buenavista Formation, and the Infierno Member and substituting Santa Teresa Formation (of much wider usage) for both a part of the Sierra Azul Formation and the Sabanilla Member. Nothing is wrong in establishing a large number of lithostratigraphic units if these are necessary to depict the configuration of a basin, but these should be grouped in a lithologically significant manner and not according to their geographic position or historical precedents. Truitt (1956a, b) named all the above units Carmita* (and Santa Teresa*), and Hatten (1957) named all the above units the Pons and Pen ˜as formations. An attempt will be made to relate the facies of the previously described stratigraphic units to see if some coherent picture of a basin, or parts of basins, can be made. It will be first assumed that the Cretaceous Bahia Honda belt, as in central Cuba, originally belonged to a separate basin. Except for some ash and siliceous material, it did not interfinger with the sedimentary belts of the clastic and platform to deep-water basin province. Although some volcanics are interbedded with the Late Jurassic, these are of the tholeiitic oceanic type and probably representative of an early rifting phase. The most important units are as follows.

San Cayetano. — This formation, characteristic of Pinar del Rio, is unfortunately too disturbed internally for drawing conclusions based on its thickness or zonation. It is well represented in the Southern Rosario and Alturas de las Pizarras del Sur areas but is not represented in the northern Rosario belt, and has not been reported at the base of the Valle de Pons unit in Pinar-1. This could be an indication that the San Cayetano is absent or thin under the northern Rosario belt and under the Pinar-1 and Valle de Pons units of the Mogotes area. It is worth mentioning that there is some evidence that the San Cayetano of the northeastern southern Rosario belt was deposited in deeper waters than in the Pizarras del Sur or the Mogotes areas. The relation between the Alturas de las Pizarras del Sur area and Pizarras del Norte unit is not clear, except that both overlie all the Mogotes area carbonate units. In the Mestanza unit, the Guasasa Formation is generally thin, commonly less than 300 ft (100 m), and only part of it has been recognized as the San Vicente Member. The upper part of this member (thin bedded with chert nodules) is overlain by the Anco´n Formation. The Jagua and Anco´n formations are also thinner. This indicates that the thinning of the Guasasa could be tectonic in origin and a consequence of the thrusting. San Cayetano Formation–Vin ˜ ales Group Boundary.—The Jagua Formation, which is present transitionally below the shallow-water carbonates of the San Vicente Member, is well developed, 100–520 ft (30–160 m) thick in the thrust sheets, showing through the window of the Mogotes area. It is quite probable that the underlying San Cayetano was thin and was deposited in shallow to moderate depth (shelf) conditions. However, in the southern Rosario belt where a probably thick San Cayetano is overlain by the deeper water sediments of the La Zarza Member, its equivalent, the Francisco Formation, is much thinner, 80 ft (25 m), and sometimes absent altogether. Evidence exists that the San Cayetano clastics under the Artemisa Formation in the southern Rosario belt are progressively younger northeastward and, therefore, equivalent to the Jagua Formation of the Mogotes area. Late Jurassic Tholeiites. — The Jagua Formation in the Cangre belt and equivalent Francisco Formation in the southern Rosario belt contain volcanics related to the dominantly volcanic El Sabalo Formation of the northern Rosario belt. The equivalent La Esperanza belt contains similar volcanics, although they are considered Tithonian instead of Oxfordian (the age

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difference might not be real; the information on the La Esperanza belt is very sketchy). The presence of these oceanic volcanics interbedded with Upper Jurassic limestones at the base of the northern Rosario and La Esperanza belts along the fault that separates the thick from the absent San Cayetano suggests, as in central Cuba, that rifting was active during that time and might have been responsible for the basin configuration. San Vicente Member–Guasasa Formation.—This unit is the only Jurassic, massive, shallow-water carbonate unit in Pinar del Rio. The age is late Oxfordian – early Tithonian, and the thickness ranges from 4920 ft (1500 m) in the Pinar-1 unit, to 985 – 2130 ft (300 – 650 m) in most outcropping units of the Mogotes area, and 230 ft (100 m) in the Alturas de las Pizarras del Sur area. It is absent or very thin (10 m; 33 ft) in most of the southern Rosario belt and absent in the northern Rosario belt, although the coeval, much deeper water, lower La Zarza is well developed in both belts. The San Vicente Member is lithologically similar to and coeval with the Hollo Colorado* and Jagu ¨ ita* formations of central Cuba; no known counterpart to the lower La Zarza exists. As already mentioned, the Pinar-1 unit is nearly autochthonous. This member therefore indicates that, during the late Oxfordian – early Tithonian, the carbonate bank conditions were much more widespread than during the late Tithonian and Cretaceous and might have extended south of the present Bahamas Platform, from Yucatan to at least as far as central Cuba. Here, however, contrary to central Cuba, evidence exists that the carbonate banks had a possibly southern equivalent deep-water facies. The lower part of the La Esperanza Formation, which is considered Tithonian, consists of interbedded limestones, sandstones, and shales. The base of this unit has never been observed nor has its stratigraphic relation to the San Cayetano. It could therefore be a partial equivalent of the San Vicente Member. Middle and Late Tithonian.— The entire basin is under deep-water conditions as indicated by the El Americano Member in the Mogotes area and the upper La Zarza Member of the Rosario belts. No outcrops of time-equivalent sediments in the Quin ˜ones belt exist. This deepening of the basin is synchronous with the basin deepening in central Cuba as indicated by the character of the Caguaguas* Formation. Cretaceous Pelagic Sediments and Cherts. — A relatively thin section of pelagic sediments and the presence of chert beds and nodules characterize the Cretaceous. This indicates deposition in the vicinity of 4000 m (13,100 ft) CCD. The approximate max-

imum thicknesses of Cretaceous pelagic sediments (excluding massive turbidites) for the different belts are as follows: Quin ˜ones belt (no pre – upper Hauterivian recognized), greater than 2950 ft (900 m); northern Rosario belt, 1540 ft (470 m); southern Rosario belt, 890 ft (270 m); and Mogotes area, 600 ft (180 m). Although these figures are very approximate, they show systematic thickening from south to north. This increase in thickness could be caused by an increase in small- to medium-size turbidite bodies. Turbiditic Sediments. —Turbidites are characteristic of the La Esperanza, Rosario, and Quin ˜ones belts. In the Tithonian and throughout the Lower Cretaceous are abundant turbiditic quartz-feldsparmuscovite sandstones and shales in the La Esperanza Formation. In the Lower Cretaceous, they are interbedded with dolomites, which, together with the presence of anhydrite, suggests a conflicting shallowwater environment of deposition. The relationship between these turbidites and the San Cayetano is always reported as a fault; however, the possibility remains that the La Esperanza Formation was transitional with and deposited over the San Cayetano. In the Albian–Cenomanian, these turbidites are interbedded with the cherts of the deep-water Santa Teresa Formation, which they can totally replace. In the northern Rosario belt, the Polier Formation, of Valanginian through Albian age, also contains similar quartzose turbiditic sandstones that are considered correlative to the upper La Esperanza Formation. The Polier Formation has been recognized only in the northern Rosario belt, where it reaches 1000 ft (300 m) in the north, thinning abruptly to the south; it is absent in the Quin ˜ones unit and the southern Rosario belt. These sandstones are time equivalent and similar in composition to the Constancia* Formation of central Cuba (although much better developed here) in the Placetas* and Cifuentes* belts. In the Upper Cretaceous are several well-developed carbonate turbidites, apparently derived from carbonate banks. The thickest and most extensive is the Cacarajı´cara Formation of late Maastrichtian age, which has its maximum development of 1475 ft (450 m) in the northern Rosario belt. It is present (originally identified as the calcareous breccia member of the Buenavista Formation) in a much reduced thickness in the southern Rosario belt. This unit correlates with and is similar to the Amaro* and Rodrigo* formations of the Cifuentes* belt in central Cuba, and in both areas, these turbidites contain a small but significant amount of quartz and volcanic detritus. These detrital components suggest a southern source.

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Manacas Formation. — In its broadest sense, this unit includes the end of the basinal sedimentation and an early stage of flysch sedimentation, abruptly followed by the wildflysch from the destruction of a basic igneous-volcanic orogenic front to the south. The presence of the thin Pica Pica Member suddenly overlain by orogenic breccia (Vieja Member) in almost every major fault slice over the entire Guaniguanico area suggests a major collapse of the orogenic front and an olistostrome of large proportions. This collapse occurred in a relatively short period of time and simultaneously with the early stages of deformation. The generally low dips, absence of overturning, and attitude of the faults indicate that here, in contrast with central Cuba, gravity was the main cause of the observed deformation. From the standpoint of reconstruction, this means that, by the Paleocene, the clastic and platform to deep basin province formed one continuous geomorphic unit. It is also intriguing that the Manacas has not been mapped at the contact between the Pizarras del Norte subbelt and the La Esperanza belt, although it underlies both. Perhaps the compositional differences between these two tectonic units, as observed by Truitt (1956a, b), is more apparent than real. However, the presence of thick Vieja Member under the La Esperanza belt in Dimas-1 indicates that the Manacas flysch deposition extended farther north than the present position of the La Esperanza belt. It appears that the clastic and platform to deep basin province is represented in a continuous stack of sheets. These sheets have been described as scales of variable limited extent. The basin represented by these sheets was asymmetric and can be summarized as follows: 1) Basement (continental or oceanic) and/or thin Jurassic clastics overlain by thick, massive, shallowwater carbonates covered, in turn, by Upper Jurassic deep-water carbonates and cherts (Mogotes area) 2) (a) East Guaniguanico Mountains: thin to thick Jurassic deep- to shallow-water clastics overlain by Upper Jurassic shallow- to deep-water carbonates and covered, in turn, by Cretaceous deepwater carbonates and cherts (eastern southern Rosario belt); and (b) west Guaniguanico Mountains: thick Jurassic deep- to shallow-water clastics overlain by thin Upper Jurassic shallow- to deep-water carbonates (western southern Rosario and Alturas de las Pizarras del Sur areas, including the metamorphosed Cangre belt)

3) (a) East Guaniguanico Mountains: middle to late Oxfordian oceanic rift volcanics overlain by thin Upper Jurassic deep-water carbonates, covered in turn by Cretaceous deep-water carbonates, clastics, and cherts with influxes of miscellaneous turbidites (northern Rosario belt including the Pizarras del Norte unit); and (b) west Guaniguanico Mountains: Tithonian oceanic rift volcanics overlain by shallow- to deep-water Lower Cretaceous carbonates and continental derived clastics overlain by deep-water cherts and clastics (La Esperanza belt) 4) Lower and Upper Cretaceous bank carbonates (Guajaibon – Sierra Azul belt) Whatever the direction of movement of the different structural units or scales, it is important to arrive at some sort of estimate of the width of basin involved. The northern and southern Rosario belts have been subdivided into 17 rather extensive structural units, the Mogotes area has been subdivided into at least 9, and the Alturas de las Pizarras del Sur area has been subdivided into 3 in addition to the La Esperanza and the Cacarajı´cara belt; this is a minimum of 31 tectonic units. Assuming that, prior to the thrusting, folding, and stacking, each unit was as wide as half the width of the Sierra de Guaniguanico (an average of 12 km [7.5 mi]), a total width of approximately 375 km (233 mi) is indicated. This extrapolative guess gives an order of magnitude of the area involved. As a comparison, the total carbonate basin in central Cuba was estimated at a minimum of 225 km (139 mi). Again, it is worth mentioning that one could be dealing with much larger areas because most of the sediments involved consist of pelagic, oceanic-type deposits, and there is much less evidence of compression than in central Cuba. The present thinking is that despite structural complications, all major movements were from south to north. If one attempts to restore these scales back to their predeformation position, that is, the higher sheets south of the lower ones, one can obtain a sequence not unlike the one of central Cuba, where the shallowwater Jurassic carbonates are to the north (Las Villas* belt) and the deep-water limestones and cherts are to the south (Cifuentes* belt). The major difference is the presence in western Cuba of a thick Jurassic clastic basin between these two extremes. The presence of oceanic tholeiites of uppermost Jurassic age suggests that, as in central Cuba, rifting was responsible for the basin configuration. The relationship of the Guajaibon –Sierra Azul belt to this basin still has

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FIGURE 104. Isla de la Juventud: metamorphics.

to be resolved, as well as the possibility of southwarddirected faults in the Rosario belt. However, the strongest argument for northward-directed movement is the fact that, except in the uppermost Cretaceous, Paleocene, and Eocene, the Guaniguanico section does not contain any appreciable amount of volcanicderived clastics. Furthermore, whatever volcanics occur, they are found in the southernmost belts (after restoration), Cangre and La Esperanza. This is evidence that the Bahia Honda igneous and volcanics were carried to their present position from south of the Guaniguanico terrane.

Metamorphics Under this heading will be grouped rocks that show great similarity to those outcropping in the Guaniguanico Mountains, but exhibit various degrees of metamorphism.

Pinar Fault Area The sediments outcropping along the southern edge of the Guaniguanico Mountains, on the northern side of the Pinar fault, although showing some metamorphism, have been described under the Guaniguanico Mountains. They form the Cangre belt.

Isla de la Juventud The metamorphic province forms the core of the outcrops in the Isla de la Juventud (see Figure 104). In a quick reconnaissance of the island, Truitt (1956a, b) pointed out the similarity between its metamorphic section and the unmetamorphosed rocks of Pinar del Rio. This part of the study will be mostly based on the work of Milla´n (1981, 1992), who, with Somin (Milla´n and Somin [1975; 1976; 1981; 1985a, b]), has studied the Cuban metamorphics for more than 30 yr. The 1988 geologic map (Pushcharovsky et al., 1988) is also based on his work. The internal structure of the Isla de la Juventud is somewhat less complex than that of the Escambray Mountains. The main feature is a large dome in the southwest area of the exposures, which has been subdivided into six structural units. These units are interpreted as folded and faulted major fault blocks. They are 1) 2) 3) 4) 5) 6)

Rio de los Indios antiform Guayabo antiform San Juan synform Nueva Gerona area Caballos tectonic wedge Sierra de las Casas nappe

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The massif has also been subdivided into five metamorphic zones where, generally speaking, zone I, the lowest grade, is in the center of the Rio de los Indios antiform, and zone V, the highest grade, occupies a small area, in the north of the massif near the Cretaceous volcanic Sabana Grande zone (Teneme Formation). Generally speaking, the metamorphic grade increases from zone I in the lowest stratigraphic unit to zone V in the uppermost part of the section, giving (as in the Escambray massif) the impression of inverse metamorphism. Here, however, the correlation between metamorphic grade and structural unit, or thrust sheet, is not as well defined as in Escambray. The metamorphism is described as moderate pressure–high temperature. The zones are characterized as follows: Zone I. It is the lowest metamorphic grade and is found at the base of the section in the Rio de los Indios antiform. The shales show the following assemblages: quartz-muscovite-biotite, quartzmuscovite-biotite-chlorite, quartz-muscovitechlorite, and quartz-muscovite. It appears to grade into zone II, but is in fault contact with zones III and IV. Zone II. It shows complete recrystallization. The sedimentary schists contain the following assemblages: garnet-biotite-muscovite, kyanitebiotite-muscovite, staurolite-biotite-muscovite, staurolite-muscovite, garnet-muscovite, staurolitebiotite-chlorite-muscovite, and zoisite-biotitemuscovite. The calcareous-silicate rocks contain some diopside and potassium feldspars. These occurrences show the beginning of the amphibolitic phase. It grades into zone I, but is in fault contact with zones III and VI. Zone III. The sedimentary schists contain the following assemblages: kyanite-staurolite-muscovite, kyanite-staurolite-biotite-muscovite, kyanitestaurolite-andalusite-muscovite, kyanite-muscovite, and garnet-muscovite. The kyanite and staurolite are abundant, and the crystals can become very large. The contacts with zones II and IV are tectonic. Zone IV. The sedimentary schists contain assemblages that represent all the combinations of garnet, kyanite, staurolite, muscovite, biotite, sillimanite, and andalusite. Oligoclase and andesine are commonly present and can be as much as 10% of the rock. The calc-silicate rocks and some marbles contain diopside (commonly partially replaced by tremolite or actinolite). The calc-silicate rocks also contain basic plagioclase, calcite, scapolite, zoisite, epidote, hornblende, phlogopite, and

potassic feldspar. The contacts with zones I, II, and III are tectonic and gradational into zone V. Zone V. This zone is transitional with and appears included within zone IV. It consists mostly of gneisses. It shows intense migmatization and granitization shown by bands of gneiss interbedded with bands of granite; commonly, these are intensely contorted. The mineral association quartz-andesine-hornblende-biotite is present. The stratigraphic section of Figure 105 shows the stratigraphic units as well as the metamorphic zone to which they belong. It should be mentioned that in most cases, the given thicknesses are estimates. Can ˜ ada Formation. — It consists of at least 1650 ft (500 m) of quartz-muscovite and quartzplagioclase-muscovite, graphitic, fine-grained schists interbedded with similar coarser grained schists. The fine-grained schists are dark gray to black when fresh because of the disseminated graphite; they are pink, reddish, or reddish brown when weathered. The coarser quartz schists are light gray to light greenish gray; they have a whitish color when weathered. Rare occasional outcrops of a dark-gray, fine- to mediumgrained marble are present. This formation, which makes up 40% of the metamorphic massif outcrops, comprises most of metamorphic zone I and zone II in structural unit 1. However, it is found in metamorphic zone III in the core of unit 2. This formation is believed to be equivalent to the Lower to Middle Jurassic San Cayetano Formation of Pinar del Rio. Agua Santa Formation. —The Agua Santa Formation consists of at least 3000 ft (1000 m) of interbedded fine-grained, graphitic schists and occasional to common marbles that can reach several meters in thickness. Locally, quartz-muscovite schists are interbedded with quartzites. The schists are greenish gray, dark gray, or black when fresh and weather reddish to reddish brown. The marbles are gray or black, fine to medium grained, commonly graphitic and schistose, and at times banded. Small amounts of gray or white, sugary dolomitic marble and calcareous quartzmuscovite-graphite schist are present. The Agua Santa Formation, which makes up 50% of the metamorphic massif outcrops, comprises most of metamorphic zone II in structural unit 1. It forms zone III and zone IV in the other structural units. This Agua Santa Formation is believed to be equivalent to the Middle to Upper Jurassic part of the San Cayetano Formation of Pinar del Rio.

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FIGURE 105. Stratigraphic section: metamorphic province Isla de la Juventud (Isle de la Juventud).

Isla de la Juventud marbles.—This informal group of lithologies consists of several types of marbles that form only 5% of the metamorphic massif outcrops. They are generally found in the troughs of the synforms. They are believed to be interbedded with, or lie above, the upper part of the Agua Santa Formation. Their relative stratigraphic position is not entirely clear. The aggregate thickness is believed to be on the order of 1500 ft (450 m), although they might not constitute a continuous stratigraphic succession.

Playa Bibijagua marble. — It consists of a black, graphitic, fossiliferous marble with interbeds of sugary dark-gray dolomite. This unit is only a few meters thick and is in stratigraphic contact with the Agua Santa Formation. The black marbles contain a possible Jurassic microfauna and cephalopods, possibly nautiloidea. Asiento Viejo marbles.—They consist of less than 100 ft (30 m) of a flaggy, banded, sometimes graphitic, marble with thin beds of metamorphosed cherts (quartzite), garnet amphibolite, and calc-silicate

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schists. It is in stratigraphic contact with the Agua Santa Formation. Colombo marbles. —They consist of more than 300 ft (100 m) of fetid gray marbles with interbedded sugary, dark-gray, tremolitic marbles. In places, thin beds of metamorphosed cherts (quartzite) and marbles derived from an intraformational breccia are present. This rock unit is in stratigraphic contact with the Playa Bibijagua marble and the Sierra Chiquita marbles. Sierra Chiquita marble. —It consists of more than 150 ft (50 m) of light-colored, commonly banded and sugary, dolomitic marbles that contain thin beds of metamorphosed chert. These are interbedded with gray, fetid, medium- to coarse-grained, gray marbles. These marbles are found only in the tectonic unit 5, where they are in stratigraphic contact with the Colombo marbles and the Sierra de Caballos marbles. Sierra de Caballos marbles. — They consist of at least 300 ft (100 m) of bluish gray, fetid marbles with thin beds of metamorphosed chert. In places, layers of garnet amphibolite, a calc-silicate rock and sugary gray dolomites. It is in stratigraphic contact with the Sierra Chiquita marble. Las Casas marble. —It consists of nearly 300 ft (100 m) of light-gray, very coarse-grained, fetid, massive, homogeneous, sometimes banded marbles. Commonly, they contain millimeter-thin laminae of a black, sugary, graphitic dolomite. In places, interbeddings of dark-gray, medium-grained marble and a white to light-gray, fine- to medium-grained marble are present. These rocks constitute the tectonic unit 6 (Sierra de las Casas nappe). La Reforma Calc-Siliceous rock. — This consists of ±100 ft (±30 m) of a commonly banded quartz and calcite rock containing abundant diopside and basic plagioclase. Generally, it contains layers of centimeter-thick, light-gray marble forming boudins. Daguilla amphibolite. —This consists of groups of strata, several centimeters to several meters thick, of hornblende (occasionally with remains of clinopyroxene), intermediate plagioclase, and garnet amphibolite. It is interbedded with a calc-silicate schist rich in diopside and basic plagioclase of sedimentary origin. This amphibolite appears to be interbedded with the Agua Santa Formation; the original rock could have been a basic tuff, basalt, or diabase, although a sedimentary origin is not completely discarded.

Isla de la Juventud Section Discussion The section exposed in the Isla de la Juventud shows a terrigenous section with interbedded carbonates that become more numerous and thicker to-

ward the upper part of the section. It is considered to be entirely of Jurassic age and equivalent to the San Cayetano and possibly Jagua and lower Vin ˜ ales. Interbedded with the carbonates and terrigenous sediments, presumably toward the upper part of the section, are some amphibolites that could be equivalent to the Oxfordian El Sabalo or the volcanics in the Cangre belt. It must be noted that most of the marbles are dark, graphitic, and with a sulfurous odor, suggesting deeper water original carbonates. The age of the metamorphism is considered synchronous with the deformation. This is supported by K-Ar age dating, giving ages ranging from 49.3 ± 3.8 to 78 ± 4.0 m.y. with a median value of 66.0 Ma or early Paleocene (Iturralde-Vinent et al., 1996). Milla´n (1981) recognizes four or five superimposed stages of deformation. As already mentioned, the metamorphism is distinctively zoned with four mesozones and one catazone. It appears inverse in relation to the section and the structures (less metamorphism in the older sediments in the cores of anticlines and more metamorphism in the younger sediments in the troughs of synclines). The zonation appears to be transitional and not related to individual thrust sheets as in the Escambray massif (perhaps it is, but the Isla de la Juventud has not been as intensively mapped and studied as the Escambray massif). The metamorphism is of high temperature and relatively low pressure compared to the high pressure and low temperature for Escambray. Inverse regional metamorphism is a phenomenon difficult to understand. The original explanation by Milla´n and Somin (1976) for the Cuban apparent reversal of metamorphism was that the hot slab of basic igneous and volcanics was thrusted over the Escambray and Isla de la Juventud massifs with a greater accompanying metamorphism of the upper layers of the section than that of the lower layers. If all the regional metamorphism was related to the activity of the arc and, therefore, to the Manicaragua granitoid (Cenomanian–Maastrichtian?), it must precede the overthrusting of the Domingo*-Cabaiguan* sequences (Maastrichtian?–middle Eocene); this is not the case. In light of available data, the thrusting hypothesis is the most likely. The predeformation width of the Isla de la Juventud is highly uncertain, but because 40 km (25 mi) are exposed, it must represent a minimum of 80 km (50 mi).

Escambray Massif This province in the Escambray massif consists of two outcropping domal uplifts near the southern

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FIGURE 106. Escambray massif.

coast of Cuba: the Sierra de Trinidad to the west and the Alturas de Sancti Spiritus to the east (see Figure 106). No similar rocks have been reported from the Camaguey Province. Gulf conducted only short reconnaissance trips to this area, so the following discussion is mostly based on the excellent work of Milla´n and Somin (1975, 1976, 1981, 1985a), Somin and Milla´n (1977, 1981), Milla´n and Myczynsky (1979), and Milla´n-Trujillo (1990). The 1988 geologic map (Pushcharovsky et al., 1988) is also based on their work. The Escambray massif is, in large part, made up of generally low-grade metamorphics that have been fairly well dated and correlated with the unmetamorphosed Upper Jurassic – Lower Cretaceous section of Pinar del Rio. The internal structure of these two domes is very complex with steep, radially directed dips. The Trinidad and the Sancti Spiritus domes have been subdivided into six structural units each or eight different

units between the two domes (see Figure 106). These units are interpreted as folded and faulted superimposed thrust sheets. Each dome has also been subdivided into distinct packets of thrust sheets called units. In general, unit 1 is found at the highest level of each dome, in contact with the Mabujina amphibolite. Units 4 –6 are found in the core of the domes. Each unit has a characteristic degree of metamorphism, generally decreasing from unit 1 to units 4– 6. It is described as high pressure and low temperature. The metamorphism of units 4– 6 shows little recrystallization and much preservation of the original texture. The shales show preservation of the original sedimentary structures with little or no schistosity. The volcanics show an assemblage of chlorite, clinozoisite-epidote, actinolite, and white mica. Quartzites can have white mica, clinozoisite, garnet, and magnetite. The marbles contain tremolite and white mica. Units 2 and 3 show complete recrystallization.

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FIGURE 107. Correlation chart, central and eastern Cuba metamorphics. The sedimentary schists have white mica and occasionally chlorite, and some show remnants of the original structures, exhibiting the same minerals found in zone I, plus lawsonite. The quartzites contain the same minerals as zone I, but with a greater variety of garnet. In unit 1, the sedimentary schists, chlorite has disappeared, and albite can be abundant. Quartzalbite-white mica schists are common. Some crystalline schists contain garnet, glaucophane, diopside, hornblende clinozoisite, epidote, zoisite, and lawsonite. In the metabasic rocks, hornblende is present instead of actinolite and so are glaucophane, garnet, clinozoisiteepidote, white mica, diopside, zoisite, and lawsonite. Quartzites can contain garnet, magnetite, glaucophane, riebeckite, hornblende, zoisite, clinopyroxenes, and diopside. White mica is always present. In marbles, zoisite is occasionally present. Figure 107 is a correlation chart of the named formations, and Figure 108 shows, from the center of the domes (units 4 – 6) toward the rim, the order of the structural units and the names of the units. In general, units 3, 4, and 6 are the internal units, whereas units 1 and 2 are the external ones. It should be

mentioned that in most cases, thicknesses are impossible to determine; however, they are occasionally estimated.

Unit 1 Herradura Formation. —It consists exclusively of quartz and quartz muscovite schists commonly with abundant graphite. It is in stratigraphic contact with the Boqueron Formation. It is characteristic of unit 1 on the northern margin of both domes. However, the degree of metamorphism is less than in unit 2, which is nearer the core of the domes. Boquerones Formation. — It is characterized by a sequence of calcareous schists (with white mica and graphite) and black to dark-gray, very foliated marbles. In places, cherts and greenschists are present. It is very similar to the Cobrito Formation.

Unit 2 Yayabo Formation. — The Yayabo Formation consists of a sequence of amphibolites made of hornblende, acid plagioclase, white mica, clinozoisite, and garnet. It contains beds of metaquartzite with

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FIGURE 108. Stratigraphy: Escambray massif.

muscovite and garnet. The Yayabo is considered Jurassic in age. This unit is shown in Pushcharovsky et al. (1988). These amphibolites appear to be independent of all other units within the massif. In their association with other rocks, they are different, both petrographically and chemically, from the Mabujina amphibolite. Unlike the Mabujina,

the Yayabo does not appear to be a remnant of basement. Loma La Gloria Formation. — It consists of a sequence of quartz schists, quartz-muscovite schists, and muscovite schists, commonly with abundant graphite. Calcareous schists are common, and sometimes, intercalations of garnet-eclogite with glaucophane

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and garnet amphibolite are present. This formation occurs in unit 2, which is peripheral to both domes. It is shown in Pushcharovsky et al. (1988). Included in this formation are bodies of multimineralic crystalline schists, commonly calcareous, that are named ‘‘Algarrobo crystalline schists.’’ K-Ar dating from four samples of white mica yielded ages from 71 to 82 m.y. (Campanian–lower Maastrichtian). Cobrito Formation. — It consists of a succession of calcareous schists and schistose marbles with a fine, rhythmic stratification. Compositionally, calcite dominates, with subordinated white mica, graphite, quartz, and variable quantities of albite. Occasionally, chlorite, clinozoisite, and lawsonite are present. Commonly included in the schists are small boudins, less affected by the metamorphism, of black dolomitic and crystalline limestone, with radiolaria (Spumellaria spp. and Nassellaria? spp.) and other organic remains. Some of the fossils have been tentatively identified as the Upper Jurassic–Neocomian Globochaetes alpina and Cadosina sp. Poorly preserved remains also exist, suggesting Calpionella or Chitinoidella. Breccias with black graphitic marble components are common. This formation is in possible stratigraphic contact with the underlying Loma la Gloria Formation and could be, at least in part, equivalent to part of the San Juan Group. This sequence is characteristic of unit 2 in both domes. This unit is shown in Pushcharovsky et al. (1988).

Unit 3 Collantes Formation. — The Collantes Formation consists of a sequence of well-bedded black marble, with abundant graphite. Schistosity is well developed, and generally, the marbles are nonfetid and nonbituminous. Chert is absent. The thickness is estimated at tens of meters. It belongs to zone II and unit 2 in the Trinidad dome. In Pushcharovsky et al. (1988), this unit is included in the Yaguanabo formation. Its stratigraphic relationships are not well known, but it conformably underlies the Loma Quivican and Charco Azul formations. The age is estimated as Upper Jurassic – Lower Cretaceous. Loma Quivican Formation.—The Loma Quivican Formation consists of estimated tens of meters of light-colored (whitish, grayish, greenish, pink, and violet), fine-grained, crystalline limestones. They show good foliation, with thin laminae of white mica and thin chert beds. In addition, they contain intercalations of greenschists (tuffaceous?), sometimes calcareous, and intraformational breccias up to 13 ft

(4 m) thick. Most of the contacts are tectonic; however, it conformably overlies the Collantes and underlies the Charco Azul and La Sabina formations. In Pushcharovsky et al. (1988), this unit is included in the Yaguanabo formation. In contrast with the limestones of the San Juan Group, this formation appears to have been deposited in an open, pelagic, marine environment. The age is considered Lower Cretaceous, possibly extending into the early Upper Cretaceous. It belongs to unit 3 in the Trinidad dome. Charco Azul Formation.—The Charco Azul Formation consists of metaquartzites, muscovite-chlorite and muscovite-quartz schists, light-colored calcareous rocks, and to a minor degree, metamorphosed sandstones with albite and chlorite and green metavolcanic schists. This unit belongs to unit 3 in the Trinidad dome. In Pushcharovsky et al. (1988), this unit is included in the Yaguanabo formation. This unit comformably overlies the Collantes Formation and is the lateral equivalent of the Loma Quivican Formation. The Yunaguabo Formation overlies this unit with apparent conformity. Near the contact of this formation, a Tithonian–Lower Cretaceous microfauna has been recognized in marbles. Yaguanabo Formation. — It consists of metavolcanic greenschists, interbedded with gray marbles and minor amounts of quartzites and siliceous mica schists. It conformably overlies the Charco Azul Formation. It is believed to be of Cretaceous age, but whole rock chemical analyses argue against being a metamorphosed equivalent of the Cabaiguan belt; the TiO2 content is much higher than in similar rocks of the Cabaiguan* sequence. This formation occurs in unit 3 of the Trinidad dome. This unit is shown in Pushcharovsky et al. (1988), but it also includes Loma Quivican, La Sabina, Charco Azul, and the Tambor formations. La Sabina Formation. —The La Sabina Formation consists of well-bedded quartzites, occasionally stained with manganese, interbedded with quartz mica schists. Occasional marbles occur. This unit belongs to unit 3 in the Trinidad dome. In Pushcharovsky et al. (1988), this unit is included in the Yaguanabo formation. It overlies the Loma Quivican Formation and appears to be the metamorphosed equivalent of the Santa Teresa Formation. Therefore, it is considered Cretaceous. El Tambor Formation. — The El Tambor Formation is described as a metamorphosed alpine-type flysch. It consists of well-bedded, rhythmic, sometimes calcareous, fine-grained chlorite schists to

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greenschists that include coarse-grained metamorphosed sandstones. Numerous interbeds of lightcolored marbles and a few beds of metaquartzite occur. This formation seems to contain olistoliths of older formations. It is assigned to the Upper Cretaceous and is believed to overlie the Yaguanabo Formation, but apparently, the contact has not been observed. This unit occurs in unit 3 of the Trinidad dome. In Pushcharovsky et al. (1988), this unit is included in the Yaguanabo formation. Note that the metamorphism of the flysch and olistostromes indicates strong tectonic activity simultaneously with, or prior to, the thermal activity of the arc. It means that some tectonic activity was early Maastrichtian or older.

Units 4–6 Naranjo Group. —The name Naranjo has been used to describe all the metamorphics of a terrigenous origin that form the lower part of the section in the Escambray massif. The Naranjo Group was named the ‘‘series of crystalline schists’’ by Thiadens (1937), the ‘‘crystalline schists of the Trinidad series’’ by Hatten et al. (1958), the ‘‘Trinidad Formation’’ by Khudoley and Meyerhoff (1971), and the ‘‘Naranjo Group’’ by Milla´n and Myczynski (1979). In 1981, Milla´n and Somin described it as a formation. In 1985a, b, Milla´n and Somin assigned new formation names to the different parts of this unit. In view of the fact that the Naranjo Formation name appears in Pushcharovsky et al. (1988), whereas some of the new units do not, it will be treated as a ‘‘group.’’ It includes the following formations. La Llamagua Formation. —It consists of an interbedding of quartz-arenites and lustrous phyllites. This unit stratigraphically underlies the basal, middle Oxfordian marbles of the San Juan Group and is considered equivalent to the Jurassic San Cayetano Formation of Pinar del Rio. It outcrops in the Trinidad dome. La Chispa Formation. — It consists of a sequence of mica schists (quartz muscovite or muscovite schists at times rich in graphite) of terrigenous origin, interbedded with quartzites, micaceous siliceous schists, metavolcanic greenschists with lawsonite, marbles, and calcareous schists. The greenschists with lawsonite and black marbles are named the Felicidad greenschists and are considered Lower–Upper Jurassic or Oxfordian. It is shown in Pushcharovsky et al. (1988) in the Trinidad dome, but in the Sancti Spiritus dome, it is included in a Jibacoa Group. San Juan Group.— It consists of ±1000(?) ft (±300? m) of well-bedded, black to dark bluish gray marbles

and calcareous schists. They are commonly graphitic and have a fetid odor. They form 40 – 45% of the outcrops of the metamorphic province. This group was named the ‘‘series of crystalline schists’’ by Thiadens (1937a, b) and ‘‘San Juan marbles’’ by Hatten et al. (1958). The group is shown in Pushcharovsky et al. (1988), but not the individual formations. The formations of the San Juan Group appear to have all been deposited under restricted, anoxic conditions, as indicated by the dark color, abundant graphite, and common hydrogen sulfide odor. Under the proper conditions, they could have served as petroleum source rocks prior to the Late Cretaceous metamorphism. Narciso Formation. —It consists of 130 ft (40 m) of beige and light- to dark-gray, finely crystalline limestones containing much detrital quartz. Many unidentifiable fossil remains occur. It outcrops in the Trinidad dome. The ammonites Perisphinctes and Microsphinctes have been identified, giving a late middle Oxfordian age. The Sauco Formation conformably overlies the Narciso. This unit is thought to correlate with the Jagua and Francisco formations in Pinar del Rio. Sauco Formation. — It consists of medium-bedded, fine- to medium grained, dark bluish gray to almost black crystalline limestones. They are very fetid and at times show a high concentration of graphite. The Sauco outcrops in the Trinidad dome. It is barren of organisms, but is assigned an upper Oxfordian –lower Tithonian age. Mayari Formation. —It consists of 300(?) ft (100? m) of gray, bluish gray to black, graphitic, crystalline limestones, always bituminous and fetid. They are commonly well stratified and thin-bedded and are intercalated with thin beds or nodules of chert. It outcrops mostly in both domes. Based on ammonites of the Perisphinctidae family, the age is considered Tithonian, but it could be extended into the Neocomian. It is considered equivalent to the Guasasa and Artemisa formations of Pinar del Rio and the Caguaguas* Formation of Las Villas* belt. In the Sancti Spiritus dome, Pushcharovsky et al. (1988) include it in the Jibacoa Group.

Escambray Massif Section Discussion The Escambray massif consists of the superposition of a minimum of six sedimentary thrust sheets (nappes) of Jurassic and Cretaceous age. This superposition shows that rocks of different facies and increasing metamorphic grade, but of equivalent age, have been stacked on each other. In addition, a

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sheet of amphibolite, the Yayabo Formation, is believed to be significantly different from the Mabujina amphibolite. As has been already mentioned, the Escambray sections show greater similarities to the unmetamorphosed Guaniguanico sections than to the central Cuba carbonate belts. This has been reported by many authors such as Somin and Milla´n (1981), Pszczo´lkowski (1987, 1999), and Iturralde-Vinent (1996). Such similarity has led these authors to postulate an early rift between the Yucatan and South America, predating the central Cuba basin succession. The development history of the massif is complex and will benefit from additional work on dating the original rocks, the stages of deformation, and the metamorphism. Several radiometric dates by the K-Ar technique (Iturralde-Vinent et al.,1996) give ages for the high-pressure metamorphism ranging from 43 to 85 m.y. or Maastrichtian. The median value is 66 m.y. or Paleocene. Stanek et al. (2006) consider the end of the subduction at approximately 70 Ma, followed by northward thrusting. It must be pointed out that the southeasternmost outcrops of thrust sheets in the Guaniguanico Mountains, the Cangre belt, contain volcanics and show inverse metamorphism of Paleocene to middle Eocene sediments (Guasasa, Anco´n, and Pica-Pica formations), predating the thrusting. Despite a general correspondence between the structural units and the metamorphic zonation, definite evidence exists that some thrusting occurred prior to the metamorphism, whereas more thrusting occurred afterward. For instance, in the Sancti Spiritus dome, it appears that the La Chispa Formation of units 4 – 6 rode over the Cobrito Formation of unit 2, with a very low angle, and both were later folded and metamorphosed. This is supported by the fact that the metamorphosed El Tambor Formation, of probable Upper Cretaceous age, is described as an alpine flysch with olistostromes. Because the age of the thermal metamorphism is not later than Maastrichtian and can be as early as the Albian, the thrusting must have occurred in the pre-Maastrichtian and even Early Cretaceous, simultaneously with the deposition of the Cabaiguan* sequence and, therefore, much earlier than the deformation of the volcanic and carbonate belts to the north. The Cretaceous Yaguanabo Formation also significantly contains volcanics. The Escambray massif is 29 km (18 mi) at its widest point. Considering the complex folding and the general high dips, 20–708, this could conservatively represent a 50-km (31-mi) distance before folding. If

the metamorphosed sediments are stacked in seven thrust sheets, the distance between the most autochthonous at the base and the most allochthonous at the top could be on the order of 300 km (186 mi) or more. The lowermost plate, units 4– 6, with the lowest metamorphic grade, consists of dominantly quartz sandstones of Middle to Upper Jurassic age, overlain by dark organic limestones of Oxfordian to Lower Cretaceous age that suggest restricted, anoxic, conditions. The uppermost plate, unit 1, with the highest metamorphic grade, shows an age-equivalent section consisting entirely of quartz-muscovite schists with graphite, suggesting a much more argillaceous original sediment. This section is overlain by lightcolored calcareous schists and marbles, with a fine rhythmic stratification, which contain radiolaria and other organic remains. This upper plate, with the highest metamorphic grade, was therefore originally farther away from a source of sediment, possibly by some 200 km (124 mi), and seems to have had more open-marine conditions in the Late Jurassic– Early Cretaceous; it was also closest to the source of metamorphism. It is impossible from the published data to draw much of a trend for the Cretaceous. There appear to be two distinct groups of facies: (1) a carbonate-chert overlain by clastics and (2) a clastic overlain by volcanics and occasional carbonates. Both groups of facies overlie the Upper Jurassic Collantes open-water carbonates and grade transitionally into each other. It is not clear if these volcanics are related to the Cabaiguan* sequence; based on the TiO2 content, Milla´n and Somin (1985b) consider them of a different origin. At any rate, these volcanics are believed to be related to the metamorphism, which would place them in a direction opposite to the less metamorphosed quartz sandy section and, consequently, away from the source of sediments. Although it has been generally assumed that the direction of thrusting was from south to north, this direction of movement is uncertain; Milla´n and Somin (1985b) and Iturralde-Vinent (1996) recognize this possibility. Therefore, the direction of the source of the clastics that accumulated during the Jurassic is unknown. It might be significant that unit 1 is present only along the northern rim of the domes and is less metamorphosed than unit 2 that underlies it. The possibility exists that there were two sets of movements along the thrusts; for instance, an early south-to-north movement before metamorphism, followed by a late north-to-south one. The above data

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FIGURE 109. Eastern Cuba, metamorphic southwestern terrane.

could also be further evidence that the metamorphism of the Escambray massif was caused by a different phenomenon than the one that was responsible for the emplacement of the Manicaragua granodiorite.

Asuncion Area: Eastern Cuba It is a relatively small area 10  12 km (6  7 mi) near the town of Asuncion (see Figure 109) and in fault contact to the west with the metamorphics of the Purial massif. The stratigraphic thicknesses have not been measured, and those shown in Figure 110 are for illustration purposes only. This area was also studied by Milla´n and Somin (1981, 1985b) Chafarina Formation. —The Chafarina Formation consists of schistose calcitic and sometimes dolomitic marbles. In the east, the marbles are dark, micaceous, banded, commonly graphitic, and sometimes bituminous and grade transitionally into calcareous schists. Toward the west, the marbles are gray, cream, and pinkish, interbedded with dark-gray marbles. Dark-gray to black cherts are present and sometimes abundant. These beds are intensely deformed in isoclinal folds, making the measurement of thickness impossible; however, this might reach several hundreds of meters. In some dark-gray marbles, near the contact with the Sierra Verde Formation, are remnants of a dark-gray limestone with Ophtal-

midium sp., Spirillina sp., Chitinoidella(?) sp., and miliolids, suggesting an Upper Jurassic age possibly extending into the Lower Cretaceous. Sierra Verde Formation. —The Sierra Verde Formation consists mostly of phyllites and metamorphosed shales, with beds of crystalline limestone, metavolcanics, and metamorphosed cherts. The phyllites constitute 80% of the section and are black when fresh, graphitic, schistose, and finely banded. They weather to pinkish, violet, creamy, and greenish and occur in groups 600–1000 ft (200– 300 m) in apparent thickness. They contain sericite, graphite, quartz, chlorite, albite, and commonly, lawsonite. The quartz grains maintain their original sedimentary shape, and abundant detrital zircon exists. Isolated beds, or groups of beds, up to 65 ft (20 m) in thickness of a green to grayish green, fine- to medium-grained, sometimes banded rock with an imperfect schistosity exist. It contains albite, chlorite, actinolite, epidote, and sphene. Glaucophane and white micas are also present but in lesser quantities. This rock appears to be metamorphosed basic volcanics. One body of amygdular basalt, with altered plagioclase phenocrysts, was also observed. Regular interbeds of gray, schistose, laminated crystalline limestones up to 10 ft (3 m) thick exist, which

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FIGURE 110. Stratigraphic section: Asuncion metamorphics, eastern Cuba – southeastern Oriente.

occasionally contains small remnants of a uncrystallized cream limestone in which microfossils have been found. The fauna consists of Calpionella sp., Nannoconus sp., and undetermined globigerinidae (Ticinella? sp. and Hedbergella? sp.), suggesting a Neocomian age, possibly extending into the Tithonian.

Common interbeds of metamorphosed cherts and an argillaceous, lustrous (sericitic), meta-silicate schist showing abundant remains of radiolaria also exist. This unit is in fault contact with the metamorphic Gu ¨ ira de Jauco Formation to the west. The nature of the contact with the Chafarina Formation has

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not been described, but it is assumed that the Sierra Verde overlies it. According to Milla´n and Somin (1985a), the Sierra Verde Formation is similar to (with less sandstone) and possibly of the same age as the La Esperanza (and possibly the Santa Teresa) Formation of northern Pinar del Rio, but not the San Cayetano Formation as previously supposed (Somin and Milla´n, 1981). It also strongly suggests the Cifuentes* belt of central Cuba.

Asuncion Area Discussion The metamorphics of Asuncion show a possible slightly metamorphosed equivalent of the La Esperanza belt in Pinar del Rio and not the Jurassic clastic sequence that is present in other metamorphic massifs. This is very significant because it indicates the extent of the La Esperanza sandy facies, and it is also suggestive of the outcrops of the unmetamorphosed Neocomian Ronda* Formation along the Tuinicu fault separating the Manicaragua belt from the Cabaiguan* sequence north of the Escambray massif in central Cuba. The relation between the metavolcanics of the Purial and the Asuncion metamorphics is tectonic and further confused by the presence of ultrabasics. However, the band of ultrabasics separating the metamorphosed Cabaiguan* sequence from the Gu ¨ ira de Jauco amphibolites is believed to be part of the major ultrabasic Mayari-Baracoa thrust sheet that formerly covered the Purial massif and was wedged along the faults that separate the Purial from the Asuncion area. It is no coincidence that in central and western Cuba, amphibolites (Mabujina, Daguilla) are also found in contact with metamorphosed sediments, suggesting that the Asuncion area was originally part of a window of metamorphosed sediments showing through the thrust sheet of amphibolite basement under the Purial metavolcanics.

BASIC IGNEOUS-VOLCANIC TERRANE This province is a belt in the Pardo (1954) sense. It includes a wide variety of igneous rocks, metamorphic rocks, volcanic rocks, igneous- and volcanic-derived sediments, and some carbonates. Originally, Pardo (1954, 1975) subdivided it into the Domingo* basic igneous and the Cabaiguan* volcanic belts. In this study, it will be subdivided into the Domingo* and Cabaiguan* sequences. The Domingo* sequence (formerly Pardo’s Domingo* belt and part of Hatten’s Manicaragua unit) is generally to the north and

south of the volcanic terrane and consists mainly of basic to ultrabasic igneous rocks; the Cabaiguan* sequence (formerly Pardo’s Cabaiguan* belt and part of Hatten’s Manicaragua unit), generally in the center of the province, consists of mostly unmetamorphosed basic to arc volcanics and associated sediments and includes an Upper Cretaceous intrusive granodiorite body. The name Zaza is widely used in the present literature to describe the area where these types of rocks occur, but unfortunately, it has suffered the same nomenclatural confusion as the other belts. The Zaza tectounit was used by Hatten et al. (1958) for much of the rocks included in the basic igneous-volcanic terrane. However, the igneous rocks outcropping north of the Placetas* and Cifuentes* belts were, in large part, considered by them to be the basement of the Las Villas tectounit, whereas they were included in the Domingo* belt by Pardo (1954). Furthermore, the Zaza unit did not include the Manicaragua unit. This terrane was named (1) the Santa Clara zone by Ducloz and Vaugnat (1962), (2) the Zaza zone by Khudoley (1967), (3) the Santa Clara zone by Meyerhoff and Hatten (1968), (4) the Seibabo and Santa Clara zones by Knipper and Cabrera (1974), (5) the Zaza and Santa Clara zones by Dilla and Garcı´a (1985), and (6) the Zaza and Manicaragua units by Hatten et al. (1988). The Zaza zone in Pushcharovsky et al. (1988) appears to coincide fairly well with Domingo* sequence of this publication. In this chapter, the names have been extended to the entire island. These two sections are intimately related, and it is believed that at one time, the Domingo* sequence, including the metamorphosed Mabuyina amphibolite, was part of an oceanic basement upon which the Cabaiguan* sequence was deposited.

Central Cuba Central Cuba is considered the type area for the basic igneous-volcanic province and will be described first, followed by western Cuba, northern Cuba, and Oriente. For each region, the Domingo* and Cabaiguan* sequences will be described together (see Figure 111). Figure 112 is a correlation chart of all the basic igneous-volcanic terrane units of central Cuba. In the literature, the Mabuyina amphibolite and the granodiorite have been referred to as the Manicaragua belt (unit) and have been associated with the Escambray metamorphics. (A possible source of geographic confusion exists. In prerevolution days, the mountains along the south coast of Cuba, near the town of Trinidad,

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FIGURE 111. Central Cuba: basic igneous-volcanic generalized geologic map.

known then as the Trinidad Mountains, now appear in the literature as the Escambray massif. It includes the Sierra de Trinidad and the Alturas de Sancti Spiritus, whereas a range of low serpentine hills near the city of Santa Clara was used to be known as the Escambray Mountains and appear under that name in many old reports.) In this publication, the Mabuyina amphibolite is considered to be part of the Domingo* sequence, and the granodiorite intrudes and is part of the Cabaiguan* sequence. In Las Villas province, the basic igneous-volcanic province is bound on the north by the Domingo* fault and its imbrications and to the south by the Escambray fault zone that is considered to correlate with the Domingo* fault.

Domingo* Sequence The Domingo* sequence consists of an association of intermediate to ultrabasic igneous and metamorphic rocks having definite layering. Its distribution is almost impossible to describe accurately. It occurs north of the Jatibonico* belt, in long linear bands

between the Las Villas* and Cifuentes* belts and between the Las Villas* and Placetas* belts. To the south, it forms a nearly complete ring at the base of the volcanic section around the Escambray metamorphics. However, it mostly occurs south of the Cifuentes* and Placetas* belts. The width of the Domingo* sequence ranges greatly from a few kilometers to as much as 22 km (13 mi) in its maximum development southeast of Santa Clara. In central Camaguey, it mostly forms a large body south and east of the Sierra de Cubitas (see Figure 113). In Las Villas province, in general, this section can be divided into a Vega-Tamarindo area, a Santa Clara– Arroyo Blanco area occurring generally south of the first, and a northern Escambray area. The VegaTamarindo and Santa Clara–Arroyo Blanco areas are separated by a possible major imbrication of the Domingo* sequence at the base or within the serpentine. The Vega-Tamarindo area of the Domingo* sequence continues in a much reduced and structurally highly disturbed condition to the northwest between the Cifuentes* and Las Villas* belts. In the northern Escambray area, they rim a window of metamorphics

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FIGURE 112. Correlation chart, basic igneous-volcanic terrane, central Cuba.

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FIGURE 113. Central Cuba, Domingo sequence.

that can be seen through the Domingo* thrust. These rocks will be described according to their location as well as to their position in the sequence. The Domingo* sequence rocks outcropping in the central part of the Camaguey province will be described under the central Camaguey area section below.

Vega-Tamarindo Area It extends from Vega to Tamarindo, between the Placetas* and Las Villas* belts (see Figure 114). It is the northern part of what recent literature refers to as the Iguara´-Perea area (Iturralde-Vinent, 1996). Its northern boundary is along the Domingo* fault over the Las Villas* and Jatibonico belts. Its southern boundary is formed by an intra–Domingo* sequence imbrication, the Jarahueca* fault, that brings the serpentinites of the Santa Clara–Arroyo Blanco area in contact with the various lithologies described as follows (see Figure 115). Intermediate Igneous Rocks. — Within this group are diorites, quartz diorites, and granodiorites that have many common characteristics. The main rock type is a gray, medium-grained quartz diorite, commonly with black hornblende and biotite crystals standing out from a salt-and-pepper matrix. Some samples have a distinct gabbroic appearance. Quartz is not visible in most hand specimens. The principal mafic is a dark-green hornblende. The feldspar is labradorite or andesine. Most of the samples from this rock show crushing of the grains and appear to

be a mechanical mixture between diorite and basic igneous rocks. K. Dickson (1955, personal communication) stated that All the quartz diorites except for some few aplitic differentiates are cataclastic in varying degrees; no occurrence is lacking some stress phenomena. Quartz is crushed and rounded into granules, which appear as relicts in patches of newly formed, limpid, untwined albite. Biotite and chlorite are bent and smeared, and feldspar laths are cracked, show undulatory extinction and incipient replacement. . .Whether this cataclasis is due to emplacement in a crystalline state, or postintrusion deformation due to thrusting, or both, is unknown. . .. A great similarity in texture and composition exists between this igneous rock and the granodiorites that form the basement below the upper (southern) plate of the Cifuentes* belt. Gulf geologists recognized another widespread type of intermediate igneous rock and named it the Andre´s* Formation. The Andre´s* Formation is believed to be synonymous with the Perea metamorphics of Hatten et al. (1958), which they consider to be the result of the intrusion of a diabase by the Tre´s Guanos granodiorite (quartz monzonite) (Hatten et al., 1988). Hatten et al. (1958) also reported the intrusion of the San Marcos troctolite by the Tre´s

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FIGURE 114. Domingo* belt, Vega-Tamarindo, Santa Clara – Arroyo Blanco areas. Guanos granodiorite. Gulf considered the San Marcos troctolite as part of the ultrabasic sequence, the Venegas* Formation, which will be described below. The similarity among all the rocks of intermediate type, and the apparent intrusion of the Perea metamorphics and the San Marcos troctolite by the Tre´s Guanos granodiorite, is the main reason for including all these units as part of the pre–Lower Cretaceous basement, the median welt, of the Las Villas unit (Placetas* and Cifuentes* belts) by Hatten et al. (1958), Meyerhoff and Hatten (1968), Meyerhoff, in Khudoley and Meyerhoff (1971), and Hatten et al. (1988). This unit consists of a mixture of hornblende dolerite, hornblende-augite gabbro, hornblende dacite or quartz porphyry, and quartz diorite. This unit appears to be the result of the intrusion of basic igneous rock by quartz diorite. As already mentioned, the Tre´s Guanos granodiorite, outcropping in the southeastern rim of the Jarahueca window, and associated with the Jobosi* Formation, is probably the metamorphosed basement of the Cifuentes* belt upper plate. Therefore, it appears that in the Vega-Tamarindo area of the Domingo* sequence, a pre – Lower Cretaceous oceanic crust was intruded by and mechanically mixed with granodiorite as indicated by the

metamorphism and the abundant cataclasis. Milla´n and Somin (1981) consider the metamorphism to be of high temperature and low pressure. The timing of this intrusion has been a long-standing problem because of the similarity of all the granitoids in central Cuba. Several K-Ar age determinations have yielded ages from 70 to 88 m.y. (Milla´n and Somin, 1981, 1985b), correlating with the Upper Cretaceous volcanic arc, although there are arguments for the Andre´s Formation to be older and metamorphosed during the Upper Cretaceous. Ultrabasics.—In this area, the serpentine is characteristically absent, and the ultrabasics are represented by the gabbros of the Venegas* Formation. Venegas* Formation. —This formation consists of an unknown thickness, but probably several thousands of feet, of fine- to very coarsely crystalline uralite gabbro, olivine gabbro, hornblende gabbro, hornblende diallage gabbro, augite-hornblende gabbro, and epidiorite. It is of dark-gray color and weathers to dark greenish gray or powdery white and black. The feldspars, commonly up to 5 mm (0.2 in.) or larger, are borderline labradorite-bytownite, commonly replaced by zeolites. The coarse-grained development is restricted to the top of the unit. It is in contact

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FIGURE 115. Stratigraphic section: Domingo* sequence, Vega-Tamarindo area.

and intermixed with the underlying intermediate igneous described above. In places, it appears to be in conformable contact with the overlying serpentine, but is very probably in fault contact. The metabasites of the Venegas* Formation are considered to have been subjected to low-pressure (<3-kbar) and high-temperature (8008C) metamorphism (GarciaCasco et al., 2003). This unit includes Hatten et al.’s (1958) San Marcos troctolite. In places, the Venegas* Formation, together with the intermediate igneous, overlies in fault contact

the Las Villas* and Jatibonico* belts, as well as the carbonates of the coastal province. Dikes. —A complex of gabbro and diabase parallel dikes cuts the Venegas* outcrop in an area south of the Jatibonico Mountains. These dikes suggest oceanic crust.

Santa Clara–Arroyo Blanco Area In this area, which is generally south and west of the preceding one, are some peculiar sediments invariably associated with some of the igneous rocks.

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FIGURE 116. Stratigraphic sections: Domingo* sequence, Santa Clara – Arroyo Blanco area.

Although this association is unquestionably tectonic, these sediments will be described first as they stand by themselves. Although they have some similarity to the Corona* Formation, they have no clear, direct relationship with any of the sediments found in any of the other belts. The section is graphically shown in Figure 116. Miguel* Formation.—In the general vicinity of the towns of Santa Clara and Placetas, and associated with fault zones in the serpentine, are outcrops of olivebrown, red, noncalcareous, slightly fissile shales, brown nonfissile mudstones, and brown calcarenites with abundant igneous grains. No sign of metamorphism

exists. The Miguel* Formation is probably included in the Vega Alta Formation in Pushcharovsky et al. (1988). This unit, which contains a rich pelagic fauna of Globigerina cretacea sl., Guembelina sp., Globigerinella sp., Globotruncana lapparenti sl., Pithonella spp., and orbitoid fragments, was considered of Maastrichtian age. It is therefore the age equivalent to the Corona*, Amaro*, and Rodrigo* formations of the Placetas* and Cifuentes* belts, but is lithologically similar to the lower – middle Eocene Vega* Formation. The faunal content suggests that this unit was deposited in deep waters.

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Although all the contacts are tectonic, it appears to structurally underlie the Domingo* sequence. The fact that the Miguel* Formation is not associated with older sediments could be an indication that it was originally deposited on some sort of basement. This could be expected in view of the fact that the preSantonian–Maastrichtian unconformity appears more pronounced southward. It shows similarities with and is equivalent to the Corona* Formation. It is an early flysch and also might have overlain the Cifuentes* belt. Associated with this unit and at the contact between the serpentine and the sedimentary Cifuentes* and Placetas* belts are outcrops of a rubble zone consisting of a crushed mixture of serpentine and sediments, as well as outcrops of calcite mesh (ophicalcite). Unnamed Metamorphic Exotics. — In the Santa Clara area, metamorphic rocks occur as exotics in a waxy type of serpentine. The size of the exotics ranges from a few centimeters to well over 1 km (0.6 mi). The zone of exotics is considered to represent the lowermost part of the section. They consist of several low- to high-grade metamorphic types such as metagraywacke, quartz-amphibole-albite schist, quartz-zoisite-chlorite schist, muscovite schist, glaucophane schist, graphite schist, amphibolites, eclogites, and phyllites. Vein quartz and pegmatite blocks are also present. Many of the exotics show plastic flow structure (recumbent teardrop) conforming to the flow structure of the serpentine. These exotics appear to have been torn from a metamorphic basement, having similarities to some metavolcanic types found in the Manicaragua belt and transported by the serpentine. The metamorphism is of the high-pressure/low-temperature type characteristic of subduction. However, the origin of some of the exotics is still unknown. Mosakovskiy et al., (1986) considers them to be a pre–late Mesozoic basement complex of a mafic type. Some of the metamorphics have given ages between 85 and 91 m.y. (Somin and Milla´n, 1981). However, the northern Escambray area metamorphism has been reliably dated at 75 – 85 Ma or Coniacian – Maastrichtian (Hatten et al., 1988; Iturralde-Vinent, 1996). This might not be a contradiction because pre–Upper Cretaceous volcanics, deposited over a basic to ultrabasic basement (rift), could have been metamorphosed during the Upper Cretaceous thermal event and later torn away and incorporated in the ultrabasics during the lower– middle Eocene obduction. Ultrabasics. — This large body of ultrabasics has a definite layered appearance in the field. Although it

is highly disturbed, cut by countless faults, and always in fault contact with sediments, a succession of distinct units is very apparent. For mapping purposes, these units have been given both formational and informal names. Serpentine. —In Cuba, it is formed from the alteration of pyroxene-bearing olivine rock grading at depth into fresh, unaltered peridotite. Its color varies from greenish black to light green. Weathered samples take a brownish or reddish appearance because of iron oxidation. The original rock was probably either harzburgite (orthorhombic pyroxene and olivine) or lherzolite (ortho- and clinopyroxene and olivine). Peridotite has been encountered in wells where it contains hypersthene and augite, as well as olivine. The serpentine can be subdivided, from base to top, into three types. Waxy Serpentine.—It is a chlorite schist with a scaly, highly sheared, glossy aspect. This shearing is unquestionably tectonic because it is commonly found near fault zones and in areas of intense deformation. Waxy serpentine is the type in which the metamorphic blocks previously described are found. The thickness is highly variable. In the Santa Clara–Arroyo Blanco area, the thickness is more than 3000 ft (1000 m), whereas in other places, only thin slivers are present. The waxy serpentine is considered to represent a shear or unstable zone at the base of the oceanic crust. Reticulated Serpentine.—It is relatively massive, with numerous thin crisscrossing bands of dark-green serpentine. Porphyritic Serpentine. — It is similar to the reticulated serpentine, but contains large bastite structures that stand out prominently as bronze or greenish cleavage flakes. Under the microscope, besides bastite, a characteristic mesh structure after olivine is seen. Many bastite grains contain relics of the original pyroxene, and rhombic pyroxene grains may be present. The total thickness of the serpentine body is unknown, but shows large variations. North of the Placetas* belt, it does not exceed a few hundred feet and, in places, might be absent altogether, whereas south of Santa Clara, it might be several thousands of feet thick. Hatten et al. (1958) estimate 8500 ft (2600 m). The distribution suggests that the serpentine forms an irregular elongated body with a lenticular cross section. The thickness irregularities are probably caused by flowage in response to tectonism. Note that north of the town of Placetas, the serpentine structurally overlies the Venegas* Formation and associated units, whereas toward the south, near Santa Clara, the presence of metamorphic exotics suggest proximity to

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a metamorphic basement. In most other areas, the waxy serpentine is in contact with the Cifuentes* belt. The serpentine is overlain by and transitional with the Gabbros G&BW*. Hatten et al. (1958) also considers the serpentine the lowest unit of the ultrabasic association. Gabbros G&BW*. — This informal name stands for gabbros that can be mapped in the field by their green (G) or black-and-white (BW) appearance. They consist of a section, estimated to be ±4800 ft (±1450 m) thick by Hatten et al. (1958), of hornblende dolerites with augite and uralite and microgabbros very similar in composition to the Venegas* Formation but are finer grained. In the lower part of the section, these lithologies are interbedded with serpentine. The dolerites are commonly cut by thick quartz veins mineralized with copper, magnetite, etc. According to Somin and Milla´n (1981), K-Ar dating of this sequence gave 160 Ma or lowermost Oxfordian. Although somewhat different in character from the Venegas* Formation, this unit is thought to be its equivalent and represents a tectonic repeat. This is suggested by (1) the presence of Cabaiguan* sequence volcanics apparently directly overlying the Venegas* north of the serpentine contact between the Placetas* and the Las Villas* belts and (2) the underlying serpentine structurally overlying the Venegas*. The base of the waxy serpentine would therefore represent the sole of a major imbrication in the Domingo* sequence, the Jarahueca fault separating the serpentine to the south from the intermediate igneous rocks to the north. The Gabbros G&BW* are overlain by the Cumbre* Formation. Hatten et al. (1958) describe a Zurrapandilla Formation consisting of all the igneous rocks with a diabasic texture, which lie above the Jarahueca serpentine and below the Fomento volcanics or the Cabaiguan tuffs. This certainly includes the Gabbros G&BW*, but it appears to include the overlying Cumbre* Formation because it includes spilites in the upper part. In Pushcharovsky et al. (1988), the Gabbros G&BW* are shown as undifferentiated gabbroic rocks. Cumbre* Formation.— This unit consists of at least 1000 ft (300 m) of uralite basalt flows, dolerites, and possible tuffs. The color is gray green, and pillow structures have been observed. The principal ferromagnesian mineral is uralite, which occurs in grains and nodules, and is commonly replaced by chlorite. Epidote is scattered throughout and associated with quartz, which is quite abundant in some areas in the form of veins. Euhedral magnetite is abundant. Some samples are identical with those of the Gabbros G&BW*.

The Cumbre* Formation shows extensive spilitilization, which is a common characteristic of submarine volcanics. Despite being a volcanic unit, the Cumbre* Formation is placed in the Domingo* sequence, and not the Cabaiguan*, because it is invariably associated with the ultrabasics and shows petrographic affinities with them. This unit was included in the Zurrapandilla Formation by Hatten et al. (1958). In Pushcharovsky et al. (1988), the unit is shown as the Zurrapandilla Formation of undifferentiated Lower Cretaceous age. It is very probably the Cumbre* Formation because it is described as basalts, diabase, cherts, and tuffs overlying undifferentiated gabbroic rocks (Gabbros G&BW* and not the serpentine as described by Hatten et al. (1958) and underlies the Matagua´ Formation. The Cumbre* Formation is overlain by the volcanics of the Cabaiguan* sequence. Although the contact is tectonically disturbed, it is believed to be a normal depositional one. Dikes. —Two main kinds of dikes are present: 1) Black-and-white, sparkling, fine-grained diorites identical with the Gabbros G&BW*. They are commonly found cutting the serpentine. 2) Hornblende trachyte and andesite porphyries. They cut the Cumbre* Formation and sometimes the overlying volcanics of the Cabaiguan* sequence.

Northern Escambray Area Mabujina Amphibolite Complex. — It consists of an unknown thickness, but possibly several thousands of feet, of green hornblende amphibolite, with crystals ranging from 1 mm (0.04 in.) to several centimeters in length; plagioclase, ranging from andesine to labradorite; relict pyroxene; sphene; and zircon. Most of the amphibolite consists of metamorphosed basalts and thin-bedded metamorphosed basaltic tuffs. Some fine-grained biotite and hornblende gneisses (meta-andesite flows) are present. The age of the amphibolites protolith has been and still is widely discussed. Mosakovskiy et al. (1986) considers them as ‘‘pre–late Mesozoic basement complex of a basic type.’’ Much of the evidence points toward an Upper Jurassic(?) to Lower Cretaceous age, with superimposed Upper Cretaceous metamorphism. Several K-Ar age determinations have given between 69 and 95 Ma, or middle Cenomanian to middle Maastrichtian, thus coinciding with the arc volcanism. Somin and Milla´n (1981) suggest that a great similarity exists between these metabasalts and those of the previously described Sierra de Rompe in Camaguey,

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although Tchounev et al. (1986) disagree. As already mentioned, blocks of similar metamorphics are included in the serpentine at the base of the serpentine in the Santa Clara–Arroyo Blanco area. It therefore appears that the Mabujina complex is related to the Domingo* sequence and, regardless of its age, represents the basement over which the Cabaiguan* sequence was deposited south of the Seibabo syncline.

Central Camaguey Area Gulf did only reconnaissance in central and western Camaguey; however, several authors published on the subject. A good summary can be found in Iturralde-Vinent (1996). The ultrabasics here are represented by a large body that occupies a broad area to the south and wraps around the east end of the Sierra de Cubitas, from west of Esmeralda to north of the town of Camaguey and to Lugaren ˜o. In addition, several isolated outcrops of serpentine are present near the north coast between the bays of Manati and Nuevas Grandes. Serpentine and associated ultrabasics form the bulk of the outcrops. Within the serpentine are inclusions of 1) Green to red, metamorphosed cherts, the Mate Prieto Formation. 2) Dark-gray diabase and basalts, the Abaiza Formation. 3) To the east of the town of Camaguey, Pushcharovsky et al. (1988) show several large metamorphic bodies, 1–3 km (0.6–1.8 mi) in length, consisting of schists, quartzites, and calcareous schists embedded in serpentine, and named La Suncia Formation (Iturralde-Vinent, 1988), suggesting the association described under the Santa-Clara–Arroyo Blanco area section above. The same map also shows, 15 km (9 mi) northwest of the city of Camaguey, a large number of elongated outcrops of gabbros and troctolites near what appears to be an elongated depression in the serpentine filled with a klippe of Upper Cretaceous volcanics. The association of gabbros and troctolites with serpentines certainly suggests the Venegas* Formation or the Gabbros G&BW*. It is therefore possible that here are elements of a succession similar to that observed in Las Villas.

Domingo* Sequence Discussion The Domingo* sequence shows an association of ultrabasics and basics that appear to be stratified and mixed at the base with at least two types of basement:

granodioritic (intrusive and/or cataclastic mixing) to the north and metamorphic (exotic inclusions) to the south. The mixing of these disparate lithologies would have occurred, in large part, during the lower–middle Eocene diastrophism that could explain the 61-m.y. dating of the Tre´s Guanos granodiorite. As indicated by the dating of the Gabbros G&BW*, the ultrabasics must be of pre-Oxfordian age and appear to be related to the oceanic crust and the submarine volcanism that occurred during the opening stages of the Upper Triassic to Lower Cretaceous rift between North America and Pangea. The pre–Upper Jurassic Cifuentes* belt basement has been identified as a granodiorite (Tres Guanos, La Rana) in the Jarahueca area. To the west, in the Socorro area, exposures of a Jurassic-dated granite and Precambrian marbles (African craton?) are near outcrops of the Jobosi* Formation and must represent the Cifuentes* belt basement. The metavolcanics of the Manicaragua belt, to the south, are probably pre–Lower Cretaceous and, together with the Domingo* sequence to the north, form the basement beneath the Cabaiguan* sequence volcanics. They were metamorphosed by the Upper Cretaceous arc, prior to the inclusion of some of their exotic fragments in the mobilized peridotite. It should be pointed out that there is a great petrographic similarity between the intermediate igneous and the Upper Cretaceous granodiorites of the Manicaragua belt to the south.

Cabaiguan* Sequence The Cabaiguan* sequence extends in a northwest– southeast direction along the central part of Las Villas and Camaguey provinces as far south as the foothills of the Escambray Mountains and apparently surrounds this feature. Its width ranges from a maximum of 26 km (16 mi) to a minimum of 10 km (6 mi). The volcanics of this belt also occur in several localities within the Domingo* sequence, as well as between the Las Villas* and Placetas* belt (see Figure 117). The Cabaiguan* sequence is characterized by a large development of volcanics and volcanic-derived sediments, and it is geographically and stratigraphically associated with the Domingo* and Manicaragua belts. The Cabaiguan* sequence is equivalent to the Tuff series of Rutten (1936) and Tuff Formation of Thiadens (1937a, b). The Cabaiguan* sequence shows significant areal variations. Six representative successions will be described. These are the Tamarindo-Camajuani area, Fomento-Taguasco area, Santo Domingo–Santa Clara

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FIGURE 117. Central Cuba, Cabaiguan sequence.

area, the north and south flanks of the Seibabo syncline, and central Camaguey. The Seibabo syncline is a large asymmetrical feature, some 50 km (31 mi) long and 15 km (9 mi) wide, located between the Domingo* sequence and the Manicaragua belt to the south. Although cut by several faults, it is relatively undisturbed and exposes the best and most complete unmetamorphosed volcanic section in Cuba. Consequently, the Seibabo syncline sections will be described first.

Seibabo Syncline, North Flank As previously mentioned, the base of the Cabaiguan* sequence volcanics rest on the Cumbre* Formation, although bedding slippage and faults obscure the true nature of the contact. The section, shown in Figure 118, is as follows. Old Volcanics*. — This unit was not studied in detail by Gulf. Its thickness ranges possibly from ±1000 to as much as 13,000 ft (±300 to as much as 4000 m) in the southeastern flank of the Seibabo syncline. The ‘‘Old Volcanics*’’ consist of a monotonous succession of well-indurated basalt flows, porphyries, siliceous tuffs, breccias, and associated volcanicderived sediments, which will be described in more detail under the section on Fomento-Taguasco area. The age is considered to be Lower Cretaceous based on their stratigraphic position. In Pushcharovsky et al. (1988), the Old Volcanics* are included in the Matagua´ Formation assigned to the Aptian–Albian. This should not be confused with Gulf’s Matagua´* Formation that

will be described below. Hatten et al. (1958) includes this unit in the Fomento volcanics. A Los Pasos Formation exists that is synonymous with the lower part of the Matagua´ Formation of Pushcharovsky et al. (1988); it must be, in part, synonymous with the Old Volcanics*. They are conformably overlain by the Obregon* Formation. Obregon* Formation. —This unit (also included in the Matagua´ Formation of Pushcharovsky et al. (1988) and Fomento Volcanics by Hatten et al., 1958) consists of 1000–1500 ft (300–450 m) of dark, porphyritic, dolerite flows interbedded with yellowish brown weathering, dark-green siliceous tuffs; black, fine-grained vitric tuffs; black-and-white spotted argillite; and tuffaceous ferruginous sandstones. No direct evidence of age exists, but it is considered Lower Cretaceous. It is comformably overlain by the Barro* Formation. Barro* Formation. — This unit (also included in the Matagua´ Formation of Pushcharovsky et al. (1988) and Fomento Volcanics by Hatten et al., 1958) consists of 500–700 ft (150–210 m) of black, slightly calcareous sandstone with characteristic spheroidal, onionskin weathering, interbedded with dark shales, conglomerates, and some porphyritic flows. The sandstones contain limestone fragments. This is the first unit where Cretaceous-looking radiolaria and some problematic remains have been found. The age is considered late Lower Cretaceous. It is comformably overlain by the Huevero* Formation.

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FIGURE 118. Stratigraphic section: Cabaiguan* sequence, Seibabo syncline– north flank.

Huevero* Formation. — This unit consists of 100– 200 ft (30 – 60 m) of dark, thin-bedded, siliceous shales, interbedded with marls and a few sandstone beds. The fauna consists of spheroidal and discoidal radiolaria. The siliceous shales show similarities to and are believed to correlate with those of the Santa Teresa* Formation of the Cifuentes* belt. This unit is not recognized in Pushcharovsky et al. (1988), and it is uncertain in what formation it is included. Based on stratigraphic position and lithologic similarities, the age is considered Albian and possibly extending into the lower Cenomanian. This formation is conformably overlain by the Gomez* Formation.

Gomez* Formation.—It consists of ±500 ft (±150 m) of black to dark-brown, thin-bedded, sometimes nodular, shaly limestone with interbedded dark-gray shales toward the base. Toward the top, the limestones are lighter colored and occasionally fragmental and interbedded with yellowish marls. Some calcareous, fine-grained sandstones are present, containing basic plagioclase, green hornblende, apatite, chlorite, volcanic grains, and bands of heavy minerals. This is a true detrital unit and is not directly associated with volcanism. It is overlain, with a hiatus or unconformity, by the Bruja* Formation; the 600-ft (185-m)-thick Seibabo* Formation, overlying the

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Gomez in the south flank of the Seibabo syncline, is missing here. This unit is included in the Provincial Formation. It is equivalent to Hatten et al.’s (1958) Serrucho Formation. This unit is certainly included in the Albian– Cenomanian Provincial Formation of Pushcharovsky et al. (1988), where it is given a thickness of 650–1650 ft (200–500 m). Here, the name Gomez Member appears as part of the Provincial Formation without explanation. The name Provincial was given by Thiadens in 1937. The fauna consists of mollusks, algal fragments, Globigerina cretacea sl., Globigerina sp., and Pithonella spp. The age is considered Cenomanian to Turonian. This formation was deposited under pelagic conditions, and it represents a pause in volcanic activity. It correlates with, and shows lithologic similarities to, the upper part of the Carmita* Formation in the Placetas* belt (it should be mentioned that there is a great lithologic similarity to Venezuela’s Cenomanian– Turonian La Luna and Querecual formations). Bruja* Formation.— This formation is the basal unit of the Pastora* Group in the south flank of the Seibabo syncline. Here, it is the only representative of this group. It is included in Hatten et al.’s (1958) Cabaiguan Tuffs. There is a unit shown as the Bruja Formation in Pushcharovsky et al. (1988), but it is not known if it has the same definition; this point will be further discussed in the Seibabo SynclineSouth Flank section. It consists of a ±300-ft (±100-m) massive flow of quartz andesite porphyry with abundant glass. It is fine grained and translucent, with abundant glass and white phenocrysts. It is dark green when fresh, but weathers to a dull earthy yellowish brown. Its outcrops stand up in hard high ridges. It has pillow structures with chilled glass borders and has interbeds of siliceous, translucent, green pumiceous beds with radiolaria. It is unconformably overlain by the Felipe* Formation. The upper 1650 ft (500 m) of the Pastora* Group present in the south limb of the Seibabo syncline were either eroded or never deposited here. No diagnostic fossils are present, but it is considered Turonian on the basis of its stratigraphic relationships. The presence of radiolaria and pillow structures indicates submarine deposition. Felipe* Formation.—It consists of 1000 ft (300 m) of yellowish brown, friable tuffaceous, igneousderived sandstones interbedded with sandy calcarenites. Near the base, a distinctive coarsely crystalline hornblende-biotite porphyry is present. In this location, a 100-ft (30-m) white massive rudist and orbitoid

reef is present, indicating local shallow-water conditions. It is included in Hatten et al.’s (1958) Cabaiguan tuffs. Dilla and Garcı´a (1985) consider it synonymous with, and therefore renamed it, the Cotorro Formation and give it a Campanian and Maastrichtian age. Pushcharovsky et al. (1988) show a Tasajera Group of Coniacian–Campanian age that includes formations names such as Cotorro, Salvador, Maguey, Hilario, Palmarito, and Felipe. All were described and named by Gulf geologists and considered at the time to be Maastrichtian in age. At the type locality of this unit, which is some 7 km (4 mi) north of here, it has been divided into three members. Here, although fully developed, subdivisions are impossible. The subdivided section is described under the Santo Domingo–Santa Clara area. A planktonic fauna exists containing Globigerina cretacea sl. and Pithonella spp. Lithothamnium sp. is also present. In this unit are exceptionally large specimens of rudists; Radiolites and Hippurites are embedded in a clay matrix. This is an intriguing occurrence of typically clear, shallow-water organisms found in an argillaceous environment. They, together with the reef limestones, suggest the presence of reefs on the flanks of volcanic islands, with some of their components falling in deeper waters. The sandstones are probably equivalent to the San Pedro Formation, and the limestones are probably equivalent to the Cantabria Formation, found along the northwestern flank of the Escambray massif (Pszczo´lkowski, 2002). There, these units are under the Vaqueria Formation marl, which is believed to span the Cretaceous–Tertiary boundary. The Felipe* is transitionally overlain by the Cotorro* Formation. The Felipe* Formation is considered lower Maastrichtian in age, perhaps extending into the Campanian. Cotorro* Formation.—It consists of ±300 ft (±90 m) of thin-bedded, green and brown, sometimes calcareous, volcanic-derived conglomerates, sandstones, and shales with occasional sandy calcarenites, tuffaceous sandstones, and vitric crystal tuffs. It is included in Hatten et al.’s (1958) Cabaiguan tuffs. They also describe a Carramayana Formation, interbedded with the Dagamal Formation, that could be part of the Cotorro* Formation. Dilla and Garcı´a (1985) consider the Cotorro Formation as equivalent to the Felipe Formation and include in it the Hilario, Magu ¨ey, and Salvador formations. They assign it a Campanian– Maastrichtian age. As mentioned above, Pushcharovsky et al. (1988) include it in the Tasajera Group of Coniacian – Campanian age.

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An abundant fauna of Globigerina cretacea sl., Globigerinella sp., Guembelina sp., Pseudorbitoides spp., sponge spicules, and radiolaria is present. The age is considered Maastrichtian. This formation is overlain by several related lithologic units that are present as isolated outcrops near the axis of the Seibabo syncline. In this study, they are given the informal name of Seibabo upper units. The nature of the contact is unclear for structural reasons. Seibabo Upper Units.—In the center of the Seibabo syncline are several lithologies, which Gulf geologists called the Curamaguey*, Yaya*, and Algarrobos* formations. The relation between these units is not clear because of structural complications. However, they all appear to be related to each other and are found in contact with and overlying the Cotorro* Formation. These units are equivalent to the Belico* Formation in the Santo Domingo –Santa Clara area. This group of formations is included in Hatten et al.’s (1958) Cabaiguan tuffs. None of the three units can be readily recognized in Pushcharovsky et al. (1988), but are included in the Coniacian – Campanian Tasajera Group. A Maastrichtian Perseverancia Group exists that apparently overlies all older units with marked unconformity; however, it is not shown along the axis of the Seibabo syncline and appears not to be related to the Seibabo upper units. Curamaguey* Formation.—The Curamaguey* Formation consists of ±150 ft (±45 m) of thin- to mediumbedded, brown and gray, calcarenites with abundant volcanic fragments. It is richly fossiliferous containing Globigerina cretacea sl., Globotruncana lapparenti sl., Globotruncana stuarti, Globotruncana contusa, Guembelina sp., Pithonella spp., Pseudorbitoides spp., Dicyclina sp., Lithothamnium sp., and, in places, abundant radiolaria. The age is considered Maastrichtian. Yaya* Formation. —The unit consists of ±300 ft (±90 m) of tan to gray, dense limestone with wispy brown markings and abundant foraminifera. It contains Globigerina cretacea sl., Globotruncana lapparenti sl., Globotruncana stuarti, Globotruncana contusa Guembelina sp., Pithonella spp., Globigerinella sp., orbitoid fragments, echinoid remains, sponge spicules, inoceramus prisms, and radiolaria. The age is also considered to be Maastrichtian. Algarrobos* Formation.—The unit consists of ±200 ft (±60 m) of marly, coarse-grained, igneous-derived sandstones and conglomerates, interbedded with fragmental sandy limestones, marls, and tan shales. It contains Globigerina cretacea sl., Globotruncana lapparenti sl., Globotruncana stuarti, Globotruncana

contusa, Guembelina sp., Pithonella spp., Pseudorbitoides spp., and Lithothamnium sp. It is considered of Maastrichtian age, possibly extending into the Paleocene. This formation was mapped by Gulf at only one locality. There appears to be an important difference of opinion between Gulf and Pushcharovsky et al. (1988) regarding the dating of the youngest volcanism in the Cabaiguan* sequence in central Cuba. Gulf considered it Maastrichtian, whereas in the map, it is considered Campanian. Bernia* Formation. —The Bernia* Formation (in Pushcharovsky et al. (1988), a Paleocene Santa Clara Formation probably includes this formation) consists of ±300 ft (90 m) of tan, pseudo-oolitic, mediumbedded, sometimes fragmental, limestone containing sparse to abundant igneous grains. The components consist of fragments of mollusks, echinoids, and foraminifera. The fossils consist of Globotruncana lapparenti sl., Guembelina sp., Pithonella spp., Lockhartia sp., Textularia sp., Ventilabrella sp., Lithothamnium sp., and miliolids. The age is considered Maastrichtian, possibly extending into the Paleocene. This unit is lithologically and faunistically related to the Santa Clara* Formation of the Santo Domingo– Santa Clara area, but its relationships with other units are not clear. Seibabo Syncline, North Flank: Discussion.— Here, during the Late Jurassic and Early Cretaceous, very active submarine volcanism occurred with an outpouring of thick basaltic flows and associated tuffs and deposition of volcanic-derived sediments. The volcanism was essentially of the basic type with alternations of more acidic periods. Toward the close of the Lower Cretaceous, volcanic activity was greatly reduced and was probably absent during the Cenomanian, which is characterized by an influx of carbonate pelagic sedimentation. During the Turonian and Senonian, there was a renewal of volcanism with outpouring of flows of a more acidic composition. Prior to the Maastrichtian, a period of nondeposition or erosion occurred that appears to be shorter than in the sedimentary belts to the north. The Campanian–Maastrichtian sedimentation began with an influx of volcanic-derived clastics and the outpouring of a prominent rhyolitic flow. Afterward, sedimentation continued, with an alternation of pelagic and shallow-water, reefoidal sediments, but always with abundant silicate detritus. Toward the end of the Cretaceous, there appears to have been a

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renewal of volcanic activity as indicated by tuffs and volcanic-derived detritus, but now under dominantly shallow-water conditions. The present thinking in Cuba is that all volcanic activity ceased by the end of the Campanian, and that only volcanic-derived material was deposited during the Maastrichtian. This problem will be discussed below. Sedimentation extended into the Paleocene with the deposition of thin calcarenites with igneousderived grains.

Seibabo Syncline, South Flank In this area, the section is mostly similar to that of the northern flank, but the marked facies differences deserve a complete description. The base of the volcanics cannot be observed here. Toward the east, between the towns of Fomento and Zaza del Medio, the volcanics are separated from the Manicaragua belt metamorphics by a thick wedge of lower – middle Eocene sediments and the Tuinicu fault. In the vicinity of this fault are outcrops of unmetamorphosed Jaguita* and Ronda* formations identical with those characterizing the Las Villas* and Cifuentes* belts to the north. Toward the west and east, at the base of the Cabaiguan* sequence, volcanics are intruded by the Manicaragua granodiorite and associated igneous. In places, numerous Upper Cretaceous diorite and diabase intrusives of the same type as those intruding the Mabujina complex exist. Generally, the Cabaiguan* sequence volcanics appear to overlie the amphibolites of the Mabujina complex, and the evidence seems to indicate that the granitoids were intruded along the contact between the two. Several authors (Milla´n and Somin, 1976, 1981; Millan-Trujillo, 1996a, b; Iturralde-Vinent, 1981, 1988, 1996) believe that the Mabujina complex is part of a metamorphosed oceanic basement over which the southern Cabaiguan* sequence was deposited. This problem will be more fully discussed under the Manicaragua belt. The Cabaiguan* volcanics, together with the Manicaragua belt, generally wrap around and radially dip away from the Escambray massif metamorphics. The Seibabo syncline – south flank succession, shown in Figure 119, is as follows. Old Volcanics*. — In this particular locality (Zaza River), the thickness may reach several thousands of feet. The lithology is similar to that of the northern flank but is conformably overlain by the Relampago* Formation.

Relampago* Formation. — The Relampago Formation (Pushcharovsky et al. [1988] include it in the Matagua´ Formation) consists of 2000 ft (600 m) of interbedded basalt porphyries, amygdular basalts, gray, banded siliceous shales, and slightly calcareous coarse volcanic sandstones, conglomerates, and agglomerates. The basalts contain abundant serpentine as replacement of the ferromagnesians. Some unidentifiable, Globigerina-looking foraminifera and other fossil remains are present. The age is considered Lower Cretaceous. It is conformably overlain by the Matagua´* Formation. Matagua´* Formation. — It consists of ±2500 ft (±750 m) of olivine and augite dolerites in thick, massive, sometimes porphyritic, flows frequently showing pillow structures. These flows are interbedded with conglomerates, tuffaceous sandstones, shales, and noncalcareous tuffs. As already mentioned, Puscharovsky et al. (1988) show more than 11,500 ft (3500 m) of an Aptian–Albian Matagua´ Formation that appears to include the Old Volcanics* as well as the Relampago*, Matagua´*, Obregon*, and Barro* formations. This unit is barren of organisms, but is considered Lower Cretaceous on field relationships. It shows similarities to and is considered the equivalent of the Obregon* and possibly, in part, of the Barro* formations in the north flank of the Seibabo syncline. It is conformably overlain by the Cristobal* Formation. Cristobal* Formation.— The Cristobal* Formation consists of ±500 ft (±150 m) of an interbedding of thin- to medium-bedded limestones and thinbedded shales. The limestones are oolitic, dense, and fragmental and contain radiolaria. The calcarenites can be coarse and contain mollusk remains and reworked oolites from the Upper Jurassic Jaguita* (or San Vicente) Formation. This unit is included in the Provincial Formation by Dilla and Garcı´a (1985) and in Pushcharovsky et al. (1988). The fossils consist of Globigerina cretacea sl., Cuneolina sp. or Dicyclina sp., Archeolithothamnium sp., and radiolaria. The age is considered Cenomanian, and it is correlative with the Diego*, Gomez*, and possibly Huevero* formations. This unit was deposited in part under deep-water conditions, but shallow waters were nearby as indicated by the presence of oolites, mollusks, and algae. This unit grades into the overlying Casanova* Formation.

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FIGURE 119. Stratigraphic section: Cabaiguan* sequence, Seibabo syncline– south flank.

The presence of Jaguita* (San Vicente?) oolites is considered extremely important because 1) The Upper Jurassic shallow-water carbonate bank facies must have extended as far south as the southernmost volcanics of the Cabaiguan* sequence. 2) During the Cenomanian, there must have been a source of Jaguita* detritus south of the Cabaiguan* sequence because they are absent in the equivalent Diego*, Huevero*, and Gomez* formations to the north. 3) The relative scarcity of associated igneous or volcanic-derived detritus indicates uplift and erosion of a block with a section similar to the Las

Villas* belt and the dumping of sediments northward into a basin previously filled with submarine basic volcanics (northward means not from the Bahamas Jurassic carbonate banks to the north). This influx of carbonate detritus happened during a pause in the volcanism that coincided with a marked change toward more acidic flows and ejecta, thus presenting some intriguing questions concerning the evolution of the basin. Except for Pardo (1975), these observations have never been reported or discussed in the literature. Casanova* Formation. — The Casanova* Formation consists of ±600 ft (±180 m) of argillaceous, dense

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to fragmental, yellowish brown limestone interbedded with thinly bedded shales. A 150-ft (45-m) flow of darkgray porphyry, weathering yellowish brown with white phenocrysts, is present in the middle of the section. Toward the top, tuffaceous sandstones and conglomerates are present as well as a rudist reef. This unit is included in the Provincial Formation by Dilla and Garcı´a (1985) and in Pushcharovsky et al. (1988). The fauna consists of Rotalipora appenninica sl., Globigerina cretacea sl., Globigerina sp., Globigerinella sp., Guembelina sp., and radiolaria. The age is considered Cenomanian. It has strong similarities to the underlying Cristobal* Formation and is the correlative of the Huevero*, Gomez*, and Diego* formations on the north flank of the Seibabo syncline. This unit was deposited mostly under deep-water conditions, but shallow waters were also present at some time as indicated by the rudist reefs. This formation grades upward into the Seibabo* Formation. Seibabo* Formation. —This unit consists of ±600 ft (±185 m) of coarsely fragmental tuffs with abundant dark-green pumice fragments, interbedded with thin beds of shale, tuffaceous sandstones, and occasional black limestones. The percentage of limestone decreases upward. Dilla and Garcı´a (1985), as well as Pushcharovsky et al. (1988), recognize the name Seibabo Formation. In the latter, it is assigned to the Cenomanian and given a thickness of 500–2950 ft (150–900 m). The fauna consists of Rotalipora appenninica sl., Globotruncana aff. Globotruncana renzi, Globigerina cretacea sl., Guembelina sp., Globigerinella sp., Meyenella sp., and radiolaria. The age is considered Turonian. There is no equivalent to this formation in the north flank of the Seibabo syncline. This unit was deposited under deep-water conditions and is conformably overlain by the Pastora* Group. Pastora* Group. —It is included in Hatten et al.’s (1958) Cabaiguan tuffs. Dilla and Garcı´a (1985) recognize a Bruja Formation, but assign it to the Coniacian and Santonian. As already mentioned, with the exception of the Bruja Formation described as 1640 ft (500 m) of Turonian andesites, marls, and tuffs, no unit is a clear-cut equivalent to the Pastora* Group in Pushcharovsky et al. (1988). This group is made of three units as follows. Bruja* Formation. —It consists of 1000 ft (300 m) of massive quartz andesite porphyry interbedded

with tuffaceous, siliceous, radiolarian shales and volcanic agglomerates containing characteristic glass bombs up to 1 ft (30 cm) in length in a yellow ash matrix. Glass-coated pillow lavas are abundant. Agabama* Formation. —It consists of ±500 ft (±150 m) of thin, even bedded, siliceous, brown to sulfuryellow, hard and soft shales. These shales contain abundant radiolaria and sponge spicules and, therefore, appear to have been deposited in very deep waters. Escambray* Formation. — This consists of ±450 ft (±140 m) of hard brown siliceous shales and massive black to tan chert with a 50-ft (15-m) augite basalt to andesite porphyry in the lower part and a 100-ft (30-m) glassy basalt porphyry with a fractured hackly appearance in the upper part. In addition to the abundant radiolaria and sponge spicules, it contains Globigerina cretacea sl. and Guembelina sp., indicating pelagic, deep-water conditions. The Pastora* Group is considered Turonian – Senonian in age and is conformably overlain by the Salvador* Formation. Salvador* Formation. — It consists of ±300 ft (±90 m) of mottled, orange, and buff, sometimes sandy, calcarenites interbedded with marls and volcanic-derived sandstones and conglomerates. Dilla and Garcı´a (1985) include a Palmarito Member in the Cotorro Formation. Pushcharovsky et al. (1988) include the Palmarito, Maguey, Hilario, and Salvador formations in the Tassajera Group of Coniacian and Campanian age. It appears that, for this map, all the Cabaiguan* sequence units younger than the Bruja* Formation have been lumped together without any attempt to unravel the stratigraphic relationships. The absence of Maastrichtian is very surprising. The presence of Maastrichtian Pseudorbitoides spp. in some of the above-mentioned units raises questions as to the age assignment of the Tassajera Group. The fossils consist of Globotruncana lapparenti sl., Globotruncana fornicata, Globigerina cretacea sl., Guembelina sp., Sulcoperculina spp., Pithonella spp., Pseudorbitoides spp., radiolaria, Inoceramus spp. prisms, and algae. The age is considered lower Maastrichtian, perhaps including the upper Campanian. The Palmarito* and Maguey* members (formerly given the rank of formation) are two characteristic lithologies of this formation: Palmarito* Member.— It is a ±100-ft (±30-m)-thick, massive, white, organic calcirudite containing large rudists (Hippurites, etc.) and other mollusks and, in places, contains coarse volcanic fragments.

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Maguey* Member.— It is a ±150-ft (±45-m)-thick flow of an amygdular basalt porphyry with translucent zeolite phenocrysts. The Salvador* Formation is lithologically very similar to and an age equivalent of the Felipe* Formation of the north flank of the Seibabo syncline. Further fieldwork might indicate that the two formations are synonymous. It is conformably overlain by the Cotorro* Formation. Cotorro* Formation. — This clastic unit is similar to that of the northern limb of the syncline. It is comformably overlain by the Hilario* Formation. Hilario* Formation. — The unit consists of ±400 ft (±120 m) of green to buff, dense to fragmental, dull, siliceous, medium-bedded to massive lithic crystal and vitric tuffs. It is very well developed in this locality. Hatten et al. (1958) describe a Dagamal Formation of olive-green to grayish blue-green well-bedded tuffs and massive tuff breccias. They report a fauna of reworked Pseudorbitoides sp. in some samples, indicating that the age cannot be older than upper Campanian. Hatten’s Dagamal is believed to be the same as the Hilario* and could include part of the underlying Cotorro* Formation. As previously mentioned, it is included in the Tassajera Group in Pushcharovsky et al. (1988). This unit is barren of fossils but is considered Maastrichtian because of its stratigraphic position. It is overlain with apparent conformity by the Seibabo upper units (see section above on the Seibabo syncline, north flank). Seibabo Syncline, South Flank: Discussion. — In the southern flank of the Seibabo syncline, the Early Cretaceous was characterized by an almost continuous and impressive outpouring of basalts. This volcanism was submarine as indicated by the common lava pillows and the unweathered and unabraded character of the particles in the associated sediments. During the Cenomanian, a marked decrease in volcanic activity was observed, whereas sedimentation continued under pelagic conditions with a sudden, and short-lived, influx of Upper Jurassic carbonate detritus originating from a southern source. The Turonian through the Senonian marks a renewal of volcanic activity, but with a definitely more acidic and explosive character. A second period of relative volcanic quiescence occurred during the early Maastrichtian. Afterward, during the remainder of the Cretaceous, a new episode of volcanism occurred accompanied by an increase in subaerial eruption. This is indicated by the character of the ejecta and the increasing presence

of shallow-water reefs associated with the volcanics and volcanic-derived sediments. No clear evidence of unconformities exists, and the entire section appears continuous.

Cienfuegos Area This area (Pszczo´lkowski, 2002) is of interest because it shows well the K/T boundary above the Cabaiguan* sequence. It is located in the lower part of the Maastrichtian–Paleocene marls of the Vaqueria Formation, above the shallow-water limestones of the Maastrichtian Cantabria Formation and the Campanian – Maastrichtian marls and conglomerates of the San Pedro Formation. The K/T boundary occurs in a zone of crustacean burrows within the Vaqueria marls, with Paleocene fossils above and Maastrichtian fossils below.

Tamarindo-Camajuani Area This area is mostly associated with the VegaTamarindo area of the Domingo* sequence. Here, the structural deformation is intense, making the estimate of thicknesses impossible and masking the true nature of the contacts. However, several stratigraphic units can be readily recognized, and a section can be pieced together as shown in Figure 120. Compared to the Seibabo syncline, the section is incomplete. It is not known if the missing components are absent through tectonism or sedimentation. Old Volcanics*. — They are poorly exposed, but basalts, basalt porphyries, and associated sediments can be readily recognized. They do not appear to be very thick. This unit overlies the Cumbre* Formation and is overlain with apparent unconformity by the Gomez* Formation. Compared to the north limb of the Seibabo syncline, at least 1600–2400 ft (500–750 m) of Obregon*, Barro*, and Huevero* formations were either eroded or never deposited. Pushcharovsky et al. (1988) show extensive outcrops of Zurrapandilla Formation in this area but very little Matagua´. It is possible that the Old Volcanics* have been included in the Zurrapandilla Formation. Gomez* Formation.— Here, it outcrops in thin slivers with its characteristic development of darkgray to black, thin-bedded to nodular limestones interbedded with dark-gray shales. It is overlain with apparent unconformity by the Cotorro* Formation. Compared to the north limb of the Seibabo syncline, 1300 ft (400 m) of the Pastora* Group and the Felipe* Formation are missing. This unit, shown in the Gulf maps, is not shown in this area in Pushcharovsky et al. (1988). Perhaps it is a matter of scale.

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FIGURE 120. Stratigraphic section: Cabaiguan* sequence, TamarindoCamajuani area.

A Cenomanian pelagic fauna is present. Cotorro* Formation.—Here, the Cotorro* Formation has a typical development of thin-bedded green and brown volcanic-derived sandstones, conglomerates, crystal tuffs, shales, and occasional sandy to argillaceous limestones. It is overlain by the Hilario* Formation. It is not shown in Pushcharovsky et al. (1988). Here, it also contains the typical pelagic Maastrichtian fauna.

Hilario* Formation. — The Hilario* Formation is represented by the green to buff, dense to fragmental dull earthy, medium-bedded to massive siliceous, and vitric crystal tuffs. It is not shown in Pushcharovsky et al. (1988). It is overlain by the Carlota* Formation. Carlota* Formation. —It consists of more than 500 ft (150 m) of three very characteristic lithologic assemblages that are given informal member ranks. Hatten et al. (1958) named this unit La Rana

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Formation. They believed it to be a late outpouring of basalt several thousand feet thick and considered it, on indirect evidence, to be of probable Coniacian– Santonian age. However, they also mention that it overlies their Dagamal Formation of probable Maastrichtian age. They propose some volcanic process (nue´ ardente) to explain this inversion of ages. They also named a Carlota Formation that has no relation to this Carlota* Formation. Dilla and Garcı´a (1985) place La Rana in the Coniacian and Santonian and make it a facies of the Dagamal Formation and equivalent to the Bruja Formation. This contradicts field evidence. In Pushcharovsky et al. (1988), the Carlota Formation is widely represented, considered Santonian and Campanian, resting on the Matagua´ Formation, and is described as tuffs, marls, shales, basic to intermediate volcanics, and reef limestones. It is obvious that it includes much more than the Carlota* Formation. The Carlota* Formation is restricted to the southeastern part of the Tamarindo-Camajuani area. Flow Breccia Member. — It consists of rounded, slightly glassy-surfaced blocks of hypersthene basalt porphyry in a noncalcareous yellow-green matrix. Porphyry Member. — It consists of pink, gray, and green hypersthene and augite basalt porphyry in thick flows. The phenocrysts are mostly labradorite and hypersthene. Rana* Member. — It consists of an interbedding of the two above lithologies with even-bedded, volcanicderived conglomerates and tuffaceous, fine to coarse sandstones with abundant colored igneous grains. The Carlota* Formation is devoid of fossils, but is considered Maastrichtian because of its stratigraphic position. It grades westward into the Turino* Formation and is overlain by the Jiquimas* Formation. Turino* Formation. —The unit consists of ±200 ft (±60 m) of calcirudite, with abundant igneous grains, interbedded with the Carlota* Formation basalt porphyries. It contains some marls and sandstones. It is the western equivalent of the Carlota* Formation. Hatten et al. (1958) describe a Carlota Formation that might in part include the Turino*. It is certainly included in the Carlota Formation of Pushcharovsky et al. (1988). The fossils consist of Globotruncana lapparenti tricarinata, Globigerina cretacea sl., Sulcoperculina cf. Sulcoperculin vermunti, Pseudorbitoides sp., Pithonella spp., miliolids, rotaloids, Archeolithothamnium sp., and mollusk and echinoid fragments. The assemblages are homogeneous, but the orbitoids and mollusk fragments have a dark coating, suggesting redeposition. The age is considered Maastrichtian.

The Turino* Formation is overlain by and could also be a facies of the Jiquimas* Formation. Jiquimas* Formation. —It consists of relatively thin, lenticular, white, massive orbitoidal reefs. The limestone is very pure, containing only rare igneous grains, although the reefs were growing directly on the underlying porphyries. It is probably included in Hatten et al.’s (1958) Carlota Formation and is certainly included in the Carlota Formation of Pushcharovsky et al. (1988). The fossils consist of Globotruncana contusa, Globotruncana stuarti, Globotruncana lapparenti sl., Guembelina sp., Pithonella spp., Vaughanina cubensis, Dicyclina sp., Pseudorbitoides sp., Lepidorbitoides(?) sp., Sulcoperculina sp., Archeolithothamnium sp., and fragments of rudists, echinoids, and algae. The age is considered Maastrichtian. It is unconformably overlain by the Taguasco* Formation. Taguasco* Formation.— This unit, consisting of a Paleocene igneous-derived conglomerate, is found only in a few outcrops in the eastern part of this area, so it will be described under the section on the FomentoTaguasco area, where it is characteristically developed. Tamarindo-Camajuani Area: Discussion. — Structural complications make it difficult to draw positive conclusions about the history of the TamarindoCamajuani area of the Cabaiguan* sequence. Thicknesses are impossible to measure because most units are bound, or repeated, by faults. In most cases, it is not known whether formations are missing because of faults, nondeposition, or erosion. However, the author believes that (1) the presence of the thin Gomez* Formation, (2) the relatively thick development of the Maastrichtian sediments, and (3) the absence or poor development of the Lower Cretaceous and the Turonian–Campanian volcanics (which are very thick in the Seibabo syncline) reflect, in large part, the sedimentary and erosional history prior to tectonism. Tentatively, one can hypothesize that the area was characterized by a period of volcanic activity during the Lower Cretaceous, although the thick Lower Cretaceous basalts present in the Seibabo syncline are essentially missing. The presence of the sedimentary Gomez* Formation indicates that, here, volcanism also paused during the Cenomanian. The missing Turonian to Santonian volcanics and derived sediments were probably eroded during the pre-Maastrichtian unconformity. In the early Maastrichtian, the volcanic activity was renewed, with late basalt outpourings, but this activity was apparently less intense than before. Volcanism

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FIGURE 121. Stratigraphic section: Cabaiguan* sequence, FomentoTaguasco area.

must have been, in large part, submarine, as indicated by the pelagic faunas of the associated sediments and the fact that the volcanic-derived sandstones show whole mineral grains with no sign of weathering or abrasion. Toward the late Maastrichtian, volcanism decreased, and several shallow-water reefs developed on the volcanoes. The Paleocene shows a great influx of igneous detritus, marking the onset of strong deformation.

Fomento-Taguasco Area This area is related to the preceding one and represents the southeastern termination of the Cabai-

guan* sequence in Las Villas. It is the easternmost continuation of the Seibabo syncline. In this area, the Late Cretaceous – early Paleogene stratigraphy becomes quite complex, with rapid facies changes; so it is necessary to subdivide it into the Taguasco vicinity to the north and the Fomento vicinity to the south. Taguasco Vicinity. —In this region, overlying the Cumbre* and underlying the Barro* Formation are several badly tectonized outcrops of volcanics. Although consisting of characteristic lithologies, they are difficult to correlate with established formations. These units will be briefly described and shown in Figure 121 in what is believed to be the proper succession, but their relative position in the section is

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questionable. All have been grouped under the informal name of Old Volcanics*. Old Volcanics*. — Here, Gulf’s geologists subdivided them into three distinctive units. This is included in the Matagua´ Formation of Pushcharovsky et al. (1988). Viajaca* Formation: — This unit consists of ±700 ft (±200 m) of thin-bedded, light-gray, red, and brown weathering, siliceous, shaly tuffs containing radiolaria. Potrerillos* Formation: — This consists of 5000 – 10,000 ft (1500 – 3,000 m) of thin-bedded, yellowbrown tuffs, with circular patches of a lighter color interbedded with the following: 1) dark, blue-gray augite, glassy, basalt porphyry 2) hornblende spherulitic porphyry 3) massive granophyre hornblende porphyry with 1-in. (2.5-cm)-long phenocrysts 4) hard, blue-green weathering to yellow-brown dense siliceous, thin-bedded tuffs 5) thin to medium-bedded platy fragmental to pumiceous tuffs 6) medium-crystalline augite quartz diorite flows Satasa* Formation: —It consists of 1000 ft (300 m) of coarsely fragmental, dark-green tuffs with abundant wavy laminated grains. It is interbedded with thick augite andesitic porphyritic flows with a cryptocrystalline to coarse-crystalline groundmass. Sandy tuffs, tuffaceous sandstones, and volcanic conglomerates are present. This formation might be in part equivalent to the Obregon* Formation, and it grades into the overlying Barro* Formation. As previously mentioned, the Old Volcanics* were not mapped in detail by Gulf geologists. Lower and Upper Cretaceous Units. —Above the Old Volcanics* are representative outcrops of the Barro*, Gomez*, Bruja*, Felipe*, and Cotorro* formations. A unit named the Saltadero* Formation and consisting of 500 –1000 ft (150 –300 m) of yellow-weathering rhyolite porphyry interbedded with laminated, dullgreen vitric tuffs, is now believed to be an inlier of the Bruja* Formation. The above units are separated by faults and do not exhibit complete sections. In the northern part of this area, they are overlain with marked unconformity by the Taguasco* Formation. Taguasco* Formation. —This unit consists of a very variable thickness, probably averaging 250 ft (75 m), of well-bedded, fine- to coarse-grained, noncalcareous sandstones and shales, which contain spherical granite and basalt boulders up to 3 ft (1 m) in diameter. The sorting is impressively bimodal. The boulders are very

fresh, showing almost no sign of weathering. Most of the components appear to be derived from acidic types of igneous rock, apparently related to the Manicaragua belt intrusive. Although volcanics (other than the basalt boulders) and limestone components are occasionally present, they are surprisingly rare. Essentially, no ultrabasic material exists. The sandstones and shales are interbedded with igneous grain-bearing limestones, marls, and occasional reef limestones. Hatten et al. (1958) describe the Eloisa conglomerate that appears to be similar to the Taguasco* Formation, but they consider it Campanian to Maastrichtian on the basis of pelagic foraminifera (the possibility of reworking exists). They also consider it to be the lateral equivalent of the Catalina Shale in the Central Depression. Pushcharovsky et al. (1988) show 1150 ft (350 m) of a Taguasco Formation of Paleocene age that is undoubtedly synonymous to Gulf’s. It shows the Taguasco Formation resting conformably in several places over the Maastrichtian Perseveranza Group shown as dominantly limestone in this area, but described as conglomerates, sandstones, siltstones, shales, and limestones. Both units rest over several older units. As already mentioned under the section on the north flank of the Seibabo syncline, this map shows the Zaza unit major break, representing the onset of the diastrophic phase, at the base of the Maastrichtian. The fauna consists of abundant Tertiary Globigerina spp., Globorotalia spp., and radiolaria. The age is considered Paleocene. The Taguasco* Formation represents a synorogenic deposit associated with and apparently riding forward with the basic igneous-volcanic province over the northern carbonate belts. It is believed to be older than the Vega* Formation, which is a similar deposit, but associated with the carbonate belts. It is, in part, equivalent to the Lucia* Formation in the Sancti Spiritus area and the Fomento* Formation in the Fomento area. It is equivalent to the Santa Clara* Formation in the Santo Domingo – Santa Clara area. The composition and texture of the Taguasco* suggest a strong, short mechanical erosion of a nearby source area, without much weathering, and the dumping of coarse erosion products into a deep basin that was being filled with fine clastic material under dominantly pelagic conditions. Interestingly, the Taguasco* Formation is restricted to the area between Cabaiguan and Tamarindo, away from the most obvious southern source of granitic material. Hatten et al. (1958) raise the possibility of a now-disappeared northern source in the basement klippes of the Cifuentes* belt.

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The Taguasco* Formation is conformably and transitionally overlain by the Bijabo* Formation, but appears to rest unconformably on many older units of the basic igneous-volcanic province. Lucia* Formation.—The Lucia* Formation outcrops southwest of Cabaiguan and consists of 200–700 ft (60–200 m) of thick-bedded, fragmental to conglomeratic, detrital limestones, with interbeds of rudist reefs, red shales, and marls. The base is unknown. In Pushcharovsky et al. (1988), it must be included in the lower–middle Eocene Bijabo Formation. The fauna consists of Globigerina spp., Globorotalia spp., Vaughanina sp., Discocyclina sp., Orbitocyclina sp., Dictyoconus cookei, Eoconuloides wellsi, Sulcoperculina sp., Pithonella spp., and Orbitoides spp. Algae are abundant. The age is considered to extend from the Maastrichtian to the lower – middle Eocene. It underlies and is in part equivalent to the Taguasco* and Isabel* formations. Toward the east, in the Sancti Spiritus area, its base appears to contain 300 ft (90 m) of a massive and thick-bedded, porcelaneous, Maastrichtian fossiliferous limestone that was called the Guayos* Formation. It is overlain by the Bijabo* Formation. Bijabo* Formation. —This unit consists of 500 – 1000 ft (150 –300 m) of thin-bedded, loosely consolidated brown sandstones, shales, and conglomerates interbedded with sandy limestones. Hatten et al. (1958) describe more than 4000 ft (1200 m) of the Zaza Formation, which undoubtedly includes the Bijabo* Formation. Pushcharovsky et al. (1988) show a Bijabo Formation that certainly includes Gulf’s Bijabo*, but must also include the Lucia* that was considered by Gulf a southern equivalent of the Taguasco* Formation. The fossils consist of Globigerina spp., Globorotalia spp., Asterocyclina sp., Discocyclina spp., Vaughanina sp., Sulcoperculina sp., ‘‘Nummulites’’ bermudezi, Orbitoides sp., and algal remains. The planktonics are occasionally abundant. The age is considered lower – middle Eocene. Although it is equivalent to the Vega* Formation, it represents the beginning of the molasse deposition. Siguaney* Formation.—This unit consists of ±300 ft (±90 m) of massive, thick-bedded, porcelaneous, fine calcarenites. It is interbedded with massive limestone conglomerates of the Sagua* type. Hatten et al. (1958) describe an identical unit and called it Loma Iguara´ Formation. Pushcharovsky et al. (1988) show a lower Eocene Sicuaney (sic) (Loma Iguara´) Formation near the town of Taguasco in sheet 13. This is obviously a typo because it is spelled Siguaney in the master legend.

The fauna consists of Discocyclina mestieri, Discocyclina spp., Vaughanina sp., Sulcoperculina sp., Asterorbis sp., Truncorotalia sp., Pithonella spp., Guembelina sp., and Orbitoides spp. Algae are abundant. It is considered lower–middle Eocene and is correlative with the Sagua* Formation in the carbonate belts to the north. It grades into the overlying Rubio* Formation. Rubio* Formation. —The unit consists of ±100 to ±500 ft (±30 to ±150 m) of thick-bedded, detrital, pellet limestone with scattered, small igneous grains, interbedded with nondetrital calcarenites and thick marls. This unit is certainly included in the Loma Iguara´ by Hatten et al. (1958) and in the Siguaney Formation in Pushcharovsky et al. (1988). The fauna consists of Discocyclina spp., Vaughanina sp., Sulcoperculina sp., Guembelina sp., ‘‘Nummulites’’ bermudezi, Globorotalia spp., Globigerina spp., radiolaria, and Orbitoides spp. The age is considered lower– middle Eocene. It disappears westward and gradually increases in thickness to the east. Although it is in fault contact with younger Tertiary sediments, it is believed to be the youngest pre– upper Eocene overlap unit of the Cabaiguan* sequence. Fomento Vicinity. — In this region, the Old Volcanics* are overlain with a strong unconformity by the Jucillo* Formation. Jucillo* Formation. — The unit consists of a volcanic pebble conglomerate with a thickness ranging from 0 to 3000 ft (0 to 900 m). All the components are derived from the underlying volcanics. Toward the top, it grades into and is interbedded with the reef limestones of the Isabel* Formation. In Pushcharovsky et al. (1988), it is shown as the Jucillo Formation, but is considered lower Eocene. It is barren of organisms, but because of its stratigraphic position and the reef limestones in its upper part, it is considered Maastrichtian. To the east, near Sancti Spiritus, the Capiro* Member (it was formerly called a formation) is distinguished by containing a high percentage of components derived from the granodiorite that outcrops nearby. Isabel* Formation. — The Isabel* Formation outcrops in the Fomento area and consists of 0– 300 ft (0 – 90 m) of reefoidal limestones with large rudists, corals, and orbitoids. Igneous-derived grains are common to abundant. In Pushcharovsky et al. (1988), it is included in the Maastrichtian Perseverancia Group, underlying the Paleocene Fomento Formation. The fossils consist of Globotruncana stuarti, Pithonella spp., Globigerinella sp., Lepidorbitoides sp., Pseudorbitoides sp., Vaughanina sp., Sulcoperculina sp.,

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and Archeolithothamnium sp. The age is considered Maastrichtian. This unit is similar and equivalent to both the Turino* and Jiquimas* formations in the TamarindoCamajuani area. It is conformably overlain by the Fomento* Formation. Fomento* Formation. — The Fomento* Formation consists of an unknown thickness of gray to pink, fine calcarenite, occurring in nodular and lenticular beds, and a coarser calcarenite containing abundant igneousderived grains. The limestones are interbedded with tan, noncalcareous, fissile shales, calcareous shales, claystone, and pink sandstones. In Pushcharovsky et al. (1988), it is shown as the Bijabo Formation, of Paleocene age overlying the Perseverancia Group. The fossils consist of Globigerina spp., Globorotalia spp., Asterocyclina sp., Discocyclina sp., Dictyoconus sp., Baggina sp., Lithothamnium sp., radiolaria, discoasters, and sponge spicules. The age is considered lower – middle Eocene, possibly extending down into the Paleocene. It is in part equivalent to the Lucia*, Taguasco* and Bijabo* formations. Fomento-Taguasco Area: Discussion. — In the Fomento-Taguasco area, some 7000–12,000 ft (2000– 3500 m) of Old Volcanics* are overlain by fragmented outcrops representative of the Upper Cretaceous lithologic units. In the north, in the vicinity of Taguasco, the volcanics are overlain, with strong unconformity, by a Paleocene conglomerate (Taguasco*) that grades into the dominantly clastic lower – middle Eocene (Bijabo*) that, in turn, is overlain by reefoidal to detrital carbonates (Siguaney*, Rubio*). In the south, in the vicinity of Fomento, the volcanics are overlain by thick Maastrichtian volcanic detritus (Jucillo*), which is overlain by Maastrichtian reefoidal to detrital carbonates (Lucia*, Isabel*) and are, in turn, overlain by lower–middle Eocene calcarenites (Fomento*) and clastics (Bijabo*). All the Paleocene and lower – middle Eocene units appear to be lateral equivalents of the Catalina Shale, of which 800 ft (240 m) were drilled, overlying 600 ft (180 m) of Eloise conglomerate (Taguasco* Formation), in Adelaide-1, some 7.5 km (4.6 mi) northwest of the town of Jatibonico. As can be seen, the present state of knowledge does not provide much information on the Cretaceous volcanic history of this area, but does provide information and dates on the diastrophism. The volcanic arc became inactive and was being eroded during the late Maastrichtian and Paleocene. The relief must have been quite low in the lower – middle Eocene as indicated

by the type of clastics and the abundance of shallowwater, fragmental, and reefoidal limestones. This was the time when the Vega* Formation flysch and the Rosas* wildflysch were being deposited in deep waters to the north over the Las Villas* and Cabaiguan*.

Santo Domingo–Santa Clara Area This part of the Cabaiguan* sequence lies east, north, and northwest of the city of Santa Clara. In this area, the outcrops are found in isolated groups surrounded by ultrabasics and, like in the Tamarindo-Camajuani area, they are severely disturbed. Here, the Cumbre* Formation also appears to underlie the Cabaiguan* sequence volcanics; however, it is difficult to establish the relationship with the overlying units. The section is shown in Figure 122. Old Volcanics*. — They (Pushcharovsky et al. [1988] include them in the Matagua´ Formation) appear to be represented by one formation. The assignment of this unit to the Old Volcanics* is strictly on the basis of lithologic similarities because its stratigraphic position is impossible to unravel. Corojo* Formation. — The Corojo* Formation consists of an unknown thickness of dense, green, siliceous tuffs, weathering yellow-brown interbedded with dark-gray, amygdular, aphanitic, porphyritic dolerites. Hatillo* Formation. — The Hatillo* Formation (Pushcharovsky et al. [1988] include it in the Matagua´ Formation) consists of ±500 ft (±150 m) of brown, in part tuffaceous, sandstone and siltstones, interbedded with pumiceous tuff, shale, marls, and fine calcarenites. The fauna consists of radiolaria, sponge spicules, and traces of Globigerina sp. The age of this unit is undetermined, but possibly Lower Cretaceous and possibly equivalent to the Barro* and Huevero* formations in the north flank of the Seibabo syncline. Diego* Formation. —The Diego* Formation consists of 300 ft (90 m) of a white, thin-bedded, marly limestone interbedded with marls and a yellow, soft, tuffaceous sandstone. Where the Diego* Formation outcrops, Pushcharovsky et al. (1988) show several areas with a pattern indicating Albian – Cenomanian outcrops, similar to the one used for the Tasajera and Santa Teresa formations, but without identification. A rich planktonic fauna is present consisting of Globigerina cretacea sl., Globigerinella sp., Rugoglobigerina sp., Hastigerinoides rohri, Planulina sp., and radiolaria. The age is considered Cenomanian. It is the northwestward equivalent of the Gomez*, Cristobal*, and Casanova* formations of the Seibabo syncline.

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FIGURE 122. Stratigraphic section: Cabaiguan* sequence, Santo Domingo– Santa Clara area.

Bruja* Formation. — In this area (not shown in Pushcharovsky et al. [1988]), only minor patches of the typical Bruja flows of quartz-andesite porphyry are present. These flows are the only representatives of the Pastora* Group. Bayate* Formation. —The unit consists of more than 1000 ft (300 m) of a soft weathering, yellowbrown, massive flow consisting of fine-grained spherulitic quartz andesite porphyry. The spherulites are filled with quartz, and the phenocrysts are altered feldspars. These flows appear to be interbedded with tuffs, which are badly weathered. This unit is petrographically very similar to the Bruja* Formation. Its

stratigraphic position is questionable because of structural complications, and it could be synonymous with Bruja*, although at one time, it was thought to belong to the Old Volcanics. Felipe* Formation.—The type locality is in this area where it has a full development. In Pushcharovsky et al. [1988], it is very probably included in the Tassajera Group. Here, it has been divided into three members. Lower Member.— This consists of 300–400 ft (90– 120 m) of dark-gray, friable tuffaceous, in part calcareous sandstones containing basic feldspars, biotite, calcite, chert, and silicified ash fragments.

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Middle Member.— It consists of 50 ft (15 m) of fine fragmental, dense, light-gray limestone interbedded with marls. An abundant planktonic fauna is present containing Globotruncana lapparenti sl., Globotruncana contusa, Globigerina cretacea sl., and Guembelina spp. This member is considered equivalent to a 100-ft (30-m), white, massive, reefoidal limestone that has been called the Roble* Formation and is considered of Maastrichtian–Campanian age. This unit unfortunately outcrops only as isolated blocks and, for this reason, is not included in the volcanic sequence of this area. Upper Member.—This member consists of 50–1000 ft (15 – 300 m) of pistachio-green shale interbedded with tuffaceous sandstones with common feldspar crystals and gray, finely fragmental, slightly sandy limestones. An abundant planktonic fauna is present, containing Globotruncana lapparenti sl, Globigerina cretacea sl, and Guembelina spp. The upper member is transitionally overlain by the Cotorro* Formation. As already mentioned, the Felipe* Formation is considered of lower Maastrichtian age, perhaps extending into the Campanian. Cotorro* Formation.—This unit consists of ±300 ft (±90 m) of its typical development of volcanic-derived clastics with occasional argillaceous limestones. It contains a characteristic Maastrichtian, pelagic fauna and is overlain by and grades into the Belico* Formation. Belico* Formation. —This unit (not recognized in Pushcharovsky et al. [1988]) consists of ±500 ft (±150 m) of white to pale-green, in part calcareous, tuffs; interbedded light-colored, limy, tuffaceous sandstones; and rare white siliceous (devitrified glass?) beds. It shows some similarities to the Hilario* Formation and is characterized by a white color and calcareous content. The fossils consist of Globotruncana lapparenti sl., Guembelina sp., Pithonella spp., Dicyclina sp., Pseudorbitoides sp., Sulcoperculina sp., Archeolithothamnium sp., mollusk fragments, and radiolaria. The age is considered Maastrichtian. It is overlain with a marked unconformity by the Santa Clara* Formation. Bernia* Formation.—This unit consists of ±300 ft (90 m) of tan pellet to oolitic, medium-bedded limestone with sparse to abundant igneous grains. The fossils consist of Guembelina sp., Lockhartia sp., Pithonella spp., and Lithothamnium sp. It is considered Maastrichtian, possibly extending into the Paleocene.

The relationships with other units are not clear, but it appears faunally and lithologically related to the Santa Clara* Formation; they might be synonymous. Santa Clara* Formation. — This unit (recognized in Pushcharovsky et al. [1988]) consists of 100 – 300 ft (33 –90 m) of white to cream, fragmental to conglomeratic limestone, with abundant algal and tuff fragments. In addition, some interbedded marls and a 10– 20-ft (3–6-m) conglomerate with boulders of white, fossiliferous Paleocene limestone without igneous grains are present. The fossils consist of Discocyclina sp., Broeckella belgica, Globorotalia spp., Globigerina pseudobulloides, Globigerina spp. (of Tertiary type), and Lithothamnium spp. (of Tertiary type), indicating a Paleocene to lower–middle Eocene age. It also contains an abundant reworked Maastrichtian fauna. It is considered to be equivalent to the Taguasco* Formation to the southeast, but older than the lower–middle Eocene part of the Sagua* Formation of the carbonate belts to the north. As already mentioned, the base of the Santa Clara* Formation marks a pronounced unconformity over the Maastrichtian because it rests on the Cotorro*, Felipe*, and Belico* formations. At Loma Capiro, northeast of the town of Santa Clara, the K/T boundary has been identified within this formation (Alegret et al., 2005). The presence of impact material has been recognized. The Santa Clara* Formation is overlain by several lower – middle Eocene units, including the Vega*, Vicente*, and Falcon* formations. Lower –Middle Eocene Units. — Under this title are grouped several units of this age whose relationships with each other are not clear. Their total thickness is ±2000 ft (±600 m). They consist of graywacke sandstones, shales, and conglomerates, with occasional marls and limestones of the Vega*, Vicente*, and Falcon* formations. The Vega* Formation has already been described; the Vicente* Formation consists of maroon shales and calcarenites with igneous grains; and the Falcon* Formation is made up of light-gray, dull calcarenites with rounded igneous components and marls. In Pushcharovsky et al., 1988, they appear under the name of Ochoa Formation of lower–middle Eocene age, consisting of conglomerates, sandstones, shales, siltstones, and limestones. These units are equivalent to the Bijabo*, Siguaney*, and Rubio* formations to the southeast. Santo Domingo–Santa Clara Area: Discussion.— In the Santo Domingo–Santa Clara area, the Cabaiguan* sequence is characterized by (1) intense volcanic activity in the Lower Cretaceous, although the

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thickness is not as great as in the other areas; (2) a volcanic pause during the Cenomanian, accompanied by pelagic carbonate sedimentation; (3) a renewal of volcanism during the Turonian–Senonian, with more acidic-type rocks characterized by rhyolitic flows; (4) a strong pre-Maastrichtian unconformity; and (5) reduced volcanic activity during the Maastrichtian, as evidenced by volcanic-derived sediments only. In the Paleocene and through the lower–middle Eocene, there was a completely new cycle. All volcanic activity ceased, and igneous detritus derived from the uplift of the Domingo* and Cabaiguan* sequences, as well as other crystalline areas, became the dominant sediment.

Central Camaguey Area The Cabaiguan* sequence rocks form most of the outcrops south of the Domingo belt, extending from Ciego de Avila to Vertientes, Amancio Rodriguez, and the vicinity of Las Tunas. As already mentioned, Gulf did only reconnaissance in this area. A major difference between the Las Villas and Camaguey provinces is that in Camaguey, the Cabaiguan* sequence is divided into two segments by a nearly continuous, fairly linear body of granodiorite and associated intrusives that extends from Ciego de Avila to east of Las Tunas. This body, like the Manicaragua belt granodiorite, is of Late Cretaceous age and, therefore, shows extensive intrusive relationships with the volcanics. In Las Villas province, the intrusion is limited to the southern edge of the Cabaiguan* sequence and intrudes only its oldest rocks. The most complete exposed sections are south of the granitoid body or south of a line running from Florida to Las Tunas. This exposure of volcanics is shown in the 1988 geologic map (Pushcharovsky et al., 1988) as the Las Tunas unit, consisting of a broad anticline where, in several fault blocks with no clear relation to each other, the older units lie under a succession of later Cretaceous overlaps. This map shows more than 28,000 ft (8500 m) of Albian to Maastrichtian volcanics. The dips are generally low (under 308), and recent information reports a considerable amount of repetition, indicating that the thickness estimates are greatly exaggerated. In Pushcharovsky et al. (1988), Contramaestre, Guaimaro, and Vidot formations represent much of the volcanic section. This nomenclature is being replaced by the section, which is shown in Figure 123, and described as follows. It is based on Iturralde-Vinent and de la Torre (1990), and IturraldeVinent (1996). Pre-Camujiro Beds. — This is the informal name for a monotonous section of intermediate flows, gray tuffs, shales, and graywacke sandstones. They contain

Hedbergella sp. and Nannoconus sp., Globigerinelloides sp., and radiolarians (Furrazola-Bermudez et al., 1964), indicating an Aptian–Albian age. The Camujiro Formation unconformably overlies these beds. Camujiro Formation.—The unit consists of approximately 11,500–13,000 ft (3500–4000 m) of volcanicderived basal conglomerates, overlain by crystalline tuffs, and basaltic to intermediate lavas. A horizon some 40 ft (12 m) in thickness consists of lenses of gray crystalline limestones containing rudists and interbedded with tuffs. The limestones contain Tepeyasia corrugata and Ichtyosarcolites sp. The tuffs contain Hedbergella sp. and Ticinella sp. The Camujiro formation is considered to be upper Albian to Turonian in age. It is considered equivalent to the Bruja* Formation in Las Villas. It is in part synonymous and replaces the Guaimaro and Contramaestre formations of Pushcharovsky et al. (1988). The Piragua Formation overlies the Camujiro with an unconformity. Intrusive contacts with the granodiorite and associated intrusives are common. Sierra de Rompe. — This unit (originally described by Somin and Milla´n, 1981) consists of an unknown thickness of metamorphosed basalts and associated volcaniclastics. Some strongly deformed marbles containing rudist remains have been described, suggesting a possible late Lower Cretaceous to Campanian age. Tchounev et al. (1986) report the presence of this unit in the Guaimaro –Las Tunas area, where they were formerly considered to be contact metamorphics between the granodiorite and the volcanics. The type of metamorphism is regional, and there is a similarity to the Mabujina complex. The position of this unit is questionable because no normal contacts with other units of the volcanic sequence have been observed. It could be equivalent to the Camujiro Formation (Millan-Tujillo, 1996) and appears to be related to Cretaceous volcanics, such as the Old Volcanics* in Las Villas province, instead of the ophiolitic association. Piragua Formation. —The Piragua Formation (in large part synonymous with, and replaces, the Vidot Formation of Pushcharovsky et al. [1988]) consists approximately of ±1400 ft (±500 m) of tuffs and basaltic to rhyolitic flows. A basal conglomerate is present, overlain by two levels of limestone lenses containing rudists. Both levels are near the base of the formation. In the upper limestone level consisting of darkgray massive limestone lenses, up to 150 ft (50 m) thick, Barretia monolifera, Pseudorbitoides sp., and Sulcoperculina sp. have been identified.

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FIGURE 123. Stratigraphic section: Cabaiguan* sequence, central Camaguey area.

The lower part of the section has been divided into two members representing different facies of the formation. Loma Yucatan Member. —It consists of a basal conglomerate overlain by thick, massive, dark-gray limestones interbedded with tuffs. The limestone contains the rudists Durrania curasavica and Vaccinites sp. It is considered of Santonian age. San Francisco Member. —This member consists of cream to pink calcareous tuffs considered to be the deep-water equivalent of the Loma Yucatan Member. The basal conglomerate is absent.

This member contains radiolaria and ammonites (Paratexanites? sp., Texasia? dentocarinata). The Piragua Formation is considered to extend from the Santonian through the Campanian. Metamorphosed contacts with the granodiorite and associated intrusives are common. It is equivalent to the Coabilla Formation that outcrops mostly north of the granodiorite body. Some rhyolitic flows at the top of the Piragua Formation have been called La Sierra Formation. Marti Formation. — The Marti Formation consists of an unknown thickness of acid flows, tuffs,

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volcanic-derived sediments, and limestones and is considered of Campanian age. It is equivalent to the Piragua Formation and shows contact metamorphism with the granodiorite. According to Pushcharovsky et al. (1988), it has a very limited distribution in the vicinity of the town of Marti. Aguilar Formation. —This unit (partially synonymous with the Contramaestre Formation) consists of 380 – 400 ft (100 – 150 m) of a monotonous section of light-cream, well-bedded tuffs, cherts, calcareous tuffs, and biomicritic limestones. The age is considered Santonian on the basis of Paratexanites sp. and Texasia? dentatocarinata. It could extend into the Campanian. Coabilla Formation.—This unit (named by IturraldeVinent, 1981) consists of an unknown thickness of medium acid- to acid-flow breccias and tuffs that have been assigned to the Campanian. This formation occurs mostly north of the granodiorite body and appears to rest directly, in fault contact, on the ultrabasics of the Domingo* sequence. Good evidence also exists that it was intruded by the granodiorite. It is the northern equivalent of the Piragua and Aguilar formations. In the upper part of the Coabilla Formation is a body of columnar andesitic basalt named La Mulata Formation, an equivalent of La Sierra. It is considered of Campanian –upper Maastrichtian age. The Duran or Jimaguayu Formation unconformably overlies the Coabilla Formation. Dura´n Formation. — This unit consists of ±330 ft (±100 m) of conglomerates, sandstones, volcanicderived sandstones, and siltstones. Some reef limestones contain a fauna of the rudists Titanosarcolites giganteus and Microcaprina tschoppi. The associated foraminifera are Vaughanina cubensis, Orbitoides apicullata, Pseudorbitoides sp., S. globosa, and a rich pelagic fauna containing Globotruncana spp. and Rugoglobigerina spp. It is considered of Campanian through Maastrichtian age. The base of the Duran Formation marks an important unconformity over all older volcanic units. This is the oldest unit not to show the effects of the granodiorite intrusion. It is the northern equivalent of the Jimaguayu Formation. Jimaguayu Formation.— It consists of 1000 ft (300 m) of fossiliferous limestones, calcirudites, marls, and sandstones. The limestones contain a rich rudist fauna, including Biradiolites mooretownensis, Titanosarcolites giganteus, Microcaprina tschoppi, and Praebarrettia sparcilirata. The associated foraminifera consist of Vaughanina

cubensis, Vaughanina guatemaltensis, Orbitoides apicullata, Orbitoides media, Pseudorbitoides sp., and Sulcoperculina globosa. A pelagic foraminifera fauna consisting of Globotruncana spp. and Rugoglobigerina spp. is also present. It is considered of Maastrichtian age, and it overlies all older units with marked unconformity. This formation is mostly confined to the south Cabaiguan* sequence outcrop area, but the presence of outliers to the north indicate that at one time, it was a widespread unit. It is equivalent to the Isabel* Formation (which is included in the Perseverancia Group in Pushcharovsky et al., 1988) in the Fomento area. It is also very probably equivalent to the Jiquimas* Formation of the Tamarindo-Camajuani area. To the south, in the Florida-Vertientes area, the Jimaguayu Formation is overlain by the Vertientes Formation. Vertientes Formation. — This unit consists of 1500–2100 ft (500–700 m) of marls, sandstone, limestones, and radiolarites of lower to middle Eocene age. It shows similarities to and is probably correlative with the Rubio* Formation. It is present mostly to the south and west of the bulk of the volcanic rock outcrops. This unit, although still considered as part of the pre– upper Eocene deformed sediments, is much less tectonized than the underlying Cretaceous. Florida Formation. — It consists of 200 ft (60 m) of calcirudites, limestones, and marls of middle Eocene age. It is in part equivalent, and lithologically similar, to the Siguaney* Formation and is in part equivalent to the Vertientes Formation. It is best developed between the towns of Ciego de Avila and Florida. Toward the center of the island, in the Maraguan area, the Jimaguayu Formation is overlain by the Maraguan Formation. Maraguan Formation. — This unit outcrops in the northeastern part of the Cabaiguan* sequence, north of the granodiorite body, and northwest of the city of Camaguey. It consists of 325 ft (100 m) of interbedded conglomerates, sandstones, siltstones, and marls. It is considered lower Eocene and overlies with marked unconformity the Upper Cretaceous Jimaguayu, Piragua, Coabilla, and Duran formations. It occupies the same stratigraphic position as the Taguasco* Formation, although the Paleocene has not been reported. It underlies with apparent conformity the Saramaguacan Formation. Saramaguacan Formation. — This consists of 1500–2100 ft (500–700 m) of an interbedding of limestones, marls, sandstones, siltstones, and shales. It is considered lower to middle Eocene.

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Central Camaguey Area: Discussion.—In Central Camaguey, the following points should be emphasized: 1) Possible late Lower Cretaceous to Campanian tholeitic basalts were only recognized in 1986, after the 1985 information cutoff date for the 1988 geologic map, (Pushcharovsky et al., 1988). Since 1985, much of the geology of the area has been revised, and most of the exposed volcanic section is now thought to be post-Albian. 2) The oldest reported carbonates are Cenomanian (Albian?) – Turonian, in the Camujiro (in part Guaimaro of Pushcharovsky et al. [1988]) Formation. Therefore, carbonates equivalent to the Cristobal* and Gomez* formations of Las Villas are not known in this area, although the Albian– Turonian is present and contains pelagic faunas. The pre-Camujiro beds could be related and show some affinities with the Huevero* Formation. 3) As already mentioned, the thickness of the Upper Cretaceous volcanics (Guaimaro and Contramaestre formations) shown in Pushcharovsky et al., 1988, is exaggerated and does not exceed 6500 ft (2000 m). This is caused by the abundant repetitions of section. The Contramaestre Formation has been found to be a structural mixture of Camujiro and Piragua formations. 4) The extensive granodiorite body intrudes all the volcanics older than the Duran Formation without being associated with regional metamorphism. Furthermore, this body seems to divide central Camaguey into two distinct areas, with the bulk of the volcanics to the south and only the Campanian Coabilla and younger formations to the north. This body is much more extensive in the subsurface than it appears on the surface. 5) A major unconformity exists at the base of the Santonian and Campanian Piragua and its equivalent, the Coabilla Formation, which is found in fault contact with the Domingo* sequence. In summary, no apparent sedimentary contact exists between the Domingo* and Cabaiguan* sequences, although tholeitic basalts of possible Early Cretaceous age have been reported. Except for the Albian tuffs, no record of Lower Cretaceous volcanism exists. During the Cenomanian – Santonian, submarine outpourings of intermediate basaltic-andesitic flows interbedded with tuffs and volcaniclastics occurred. It is not clear whether there was a pause in volcanism in the Cenomanian as in Las Villas province, but this

is possible because a major hiatus exists between the Camujiro and the pre-Camujiro beds. During the Santonian–Campanian interval, an accumulation of tuffs, of intermediate to acid composition, and other volcaniclastics occurred, interbedded with carbonate bodies possibly equivalent to part of the Pastora* Group. During the Coniacian, there was some deformation and uplift before the deposition of the Campanian Piragua, Coabilla, and Marti formations. The deformation continued, and a second unconformity occurred at the base of the Campanian – Maastrichtian Duran and Yaquimas formations. This unconformity very possibly correlates with the preMaastrichtian unconformity in Las Villas province. The overlying units are characterized by further deposition of tuffs and volcanoclastic sediments and are probably correlative to the Cotorro* and Hilario* formations of the Tamarindo-Camajuani area. The granodiorite body shows contact metamorphism with all Campanian and older units. Several smaller associated intrusives are concentrated around Guaimaro, suggesting the presence of a volcanic center. The close of the Maastrichtian is marked here, as in Las Villas province, by the influx of carbonate sedimentation characterized by the Jimaguayu Formation, correlative with the Jiquimas*. The Paleocene is not reported, although the Maraguan could be a counterpart of the Taguasco* Formation. The middle Eocene clastics, carbonates, and marls of the Florida and Vertientes formations, similar and correlative with the Siguaney* and Rubio* formations, are also unconformable over older sediments, but are not as involved in the deformation as is the lower Tertiary in the northern carbonate belts of Las Villas and Camaguey provinces. Although tuffs are reported in the Maastrichtian, the present thinking of Cuban workers is that here, as in Las Villas province, volcanism ceased at the close of the Campanian. In this area, the Domingo* is separated from the Cabaiguan* sequence by a series of faults, which probably represents the highly deformed expression of a Cabaiguan* sequence thrust sheet riding northward over the Domingo*.

Intrusives Part of this area was included in the Manicaragua tectounit. Hatten et al., 1958, named this unit the Manicaragua tectounit; it was redefined and described by Hatten et al., 1988.

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FIGURE 124. Central Cuba, Cabaiguan sequence intrusives.

It outcrops in Las Villas province, where it consists of a narrow band of granodiorite and metavolcanics, commonly ±10 km (±6 mi) wide, north of the Escambray massif. It extends from the vicinity of Cumanayagua through Manicaragua to Sancti Spiritus. In the Camaguey province, an assemblage of granodioritic intrusive rocks (already mentioned) forms the backbone of the province and outcrops almost continuously from Ciego de Avila to Las Tunas. In this study, these granodiorites and associated metamorphics will be included in the Cretaceous volcanic complex of the Cabaiguan section (see Figure 124). Escambray Massif Area. — Sancti Spiritus Granodiorite.—In the recent literature, no formal name exists for this group of related granitoids. Hatten et al. (1958) included it in the Manicaragua tectounit. I feel that it should be separated from the Mabujina amphibolite for being genetically different. It is a large intrusive body ranging in composition from diorite to granodiorite to plagiogranite. The plagioclase ranges from andesine to labradorite. Sometimes, it has well-developed intergrowths of quartz. It generally contains hornblende and biotite. Near the contact with the Mabuyina, many scattered inclusions of rounded to angular amphibolite are present. Undeformed pegmatite dikes cut both the Mabuyina complex and the granodiorite. Radiometric dates from the granodiorite (10 samples) range from 60 to 93 Ma, but have a median value

of 84 Ma or Santonian. It is worth mentioning that some dates of the Escambray metamorphism are as young as 70 Ma or middle Maastrichtian and as old as 95 Ma or middle Cenomanian. At any rate, there appears to be no question that the age of the intrusion, as well as that of the corresponding more acidic volcanic phase of the Cabaiguan* sequence, is Upper Cretaceous. As already mentioned, this body shows intrusive relationships with the Lower Cretaceous volcanics. Porvenir Formation. — The Porvenir Formation consists of badly weathered metavolcanics in contact with the granodiorite. A mixture of lithologies exists such as metatuffs, quartzites, and marbles. Central Camaguey Area. — In this area, only a granodiorite body of composition and age similar to that of the Sancti Spiritus granodiorite is present. Radiometric dates from the granodiorite (28 samples) range from 58 to 99 Ma, but have a median value of 78 Ma or lower Campanian. It shows intrusive relationships with all the units from the possible Lower Cretaceous Sierra de Rompe sequence to the Campanian Piragua and Coabilla formations. A cluster of related granitoid intrusions in the Cabaiguan* sequence, as well as in the granodiorite proper in the vicinity of Guaimaro, suggests the location of a former volcanic center. The main difference between these two granodiorite bodies is their relation to the Cabaiguan* sequence exposures; the Sancti Spiritus body is to the

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south of the exposures, whereas in central Camaguey, it is located to the north of most of them.

Campanian–Maastrichtian Problem Here, it seems appropriate to discuss the dating of the end of the volcanism because there is a point of disagreement between my interpretation and the current opinion of several authors. Gulf considered the volcanism in Las Villas province to have continued into the Maastrichtian. However, Pushcharovsky et al., 1988, indicate that the volcanism ceased at the end of the Campanian and considers several units that were dated by Gulf as Maastrichtian to be Campanian or older. In the Camaguey province, Pushcharovsky et al. (1988), IturraldeVinent and de la Torre (1990), and Iturralde-Vinent (1996) show an unconformity and hiatus below the Maastrichtian separating a lower Campanian and older volcanic section from an upper nonvolcanic one. Because only a maximum of 3 m.y. are involved, this might appear as splitting hairs. However, this difference has an important effect on the age assignment of certain unfossiliferous units, thus affecting the reconstruction of the geologic history. Having no access to documents with evidence supporting the pre-Maastrichtian cessation of volcanic activity in all of central Cuba, what follows is a review of the reasons why Gulf’s geologists thought that some volcanic activity in this area continued until at least the lower part of the Maastrichtian. One idea to keep in mind during this discussion is the common Cuban problem of the reworking of older faunas into younger sediments. 1) Pelagic assemblages. In the Cifuentes* belt, the Amaro* and Rodrigo* formations contain a rich pelagic assemblage of the Globotruncana lapparenti group, which was assigned a Santonian through Maastrichtian age. P. Bro ¨ nnimann considered that much of the Amaro* Formation pelagic fauna pertained to the Globotruncana calcarata–Globotruncana fornicata and Globotruncana ganseri zones of Campanian–lower Maastrichtian age. The Rodrigo* Formation fauna pertains to the Globotruncana mayaroensis zone and was therefore considered to be of upper Maastrichtian age. Pushcharovsky et al. (1988) agree with this age determination and considers the Amaro (and equivalent Camajan) Formation, which includes Gulf’s Rodrigo* Formation, to be of Maastrichtian age. In the Cabaiguan* sequence, the same assemblages have been iden-

tified in the Algarrobos*, Belico*, Cotorro*, Felipe*, and Yaya* formations. 2) Benthonic assemblages. Orbitoid assemblages are considered mostly of Campanian – Maastrichtian age. The Vaughanina-Orbitoides-Lepidorbitoides assemblage was considered definitely of Maastrichtian age. This assemblage was identified in the Algarrobos*, Jiquimas*, Salvador*, and Turino* formations. The Roble* Formation, containing primitive pseudorbitoids, was considered of lower Maastrichtian–Campanian(?) age and to be an equivalent to the middle member of the Felipe* Formation. Of the above-mentioned units considered by Gulf to be of Maastrichtian age, the Cotorro* Formation is crucial because it is represented in the Seibabo syncline, north and south flanks; the Tamarindo-Camajuani area; and the Santo Domingo – Santa Clara area. It is poorly represented to absent in the FomentoTaguasco area. The relationships of the Cotorro* with other units is as follows. 1) In the Seibabo syncline–north flank and the Santo Domingo–Santa Clara area, it conformably overlies the volcanic Felipe* Formation, considered by Gulf to be lower Maastrichtian–Campanian(?). 2) In the Seibabo syncline– south flank, it conformably overlies the volcanic Salvador* Formation, which is similar to, and possibly synonymous with, the Felipe*. 3) In the Tamarindo-Camajuani area, it lies with strong unconformity over the Cenomanian Gomez* Formation. 4) In the Fomento-Taguasco area, it is either absent because of a Paleocene unconformity or represented by the Jucillo* conglomerates, interbedded with the Maastrichtian Isabel* Formation, and lying unconformably over the Old Volcanics*. 5) The Cotorro* Formation is definitely overlain by the Hilario* Formation, which is made of massive tuffs, the Belico* Formation, that definitely contains tuffs and tuffaceous sandstones, and the Turino* Formation, which, consisting mostly of calcarenites, is interbedded with the basalt porphyries and breccias of the Carlota* Formation. As previously mentioned, the Carlota* Formation, La Rana of Hatten et al. (1958), was considered by them to overlie the Maastrichtian and/or upper Campanian Dagamal (Hilario*) Formation, although they assign it to the Coniacian–Santonian. Their reasoning is not entirely clear.

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FIGURE 125. Correlation chart, Cabaiguan* sequence, Upper Cretaceous.

Overlying these Maastrichtian volcanics is a group of Maastrichtian, reefoidal to detrital, carbonate units that resemble the Camaguey province Duran and Jimaguayu´ formations; these are the Isabel*, Jiquimas*, Bernia*, and the Seibabo upper units. In Pushcharovsky et al. (1988), most of the units mentioned above are included in the Tassajera Group of Coniacian –Campanian age. It is therefore possible that the unconformity is upper Campanian in age (see Figure 125). In Camaguey, it separates the upper Maastrichtian deposits from the underlying Campanian, whereas in Las Villas province, it separates the lower Maastrichtian from Campanian and older sediments. In southeastern Las Villas, the Maastrichtian (Cotorro*, Jucillo*) overlies Cenomanian to Lower Cretaceous volcanics; in northwestern Las Villas, the Maastrichtian –Campanian(?) (Felipe*) overlies the Turonian (Bruja*); and in southeastern Las Villas, sedimentation was apparently uninterrupted. The late phases of volcanism, therefore, extended into the lower Maastrichtian in Las Villas, but were not recorded in central Camaguey because no sediments accumulated there until the upper Maastrichtian. The evidence in Las Villas indicates that the volcanism ended by the middle Maastrichtian and was overlain by carbonate deposits similar to, and contemporaneous with, the Duran and Jimaguayu´ formations.

This disagreement will certainly not be settled here, but it is not clear why the Amaro* and Rodrigo* formations are accepted as Maastrichtian, whereas the above-mentioned Cabaiguan* sequence units, with an identical fauna, are not. However, the Isabel* and Santa Clara* formations considered by P. Bro ¨ nnimann as Maastrichtian and Maastrichtian – Paleocene, respectively, on the same faunal evidence, are considered part of a Maastrichtian and later overlap, the Perseverancia Group and Santa Clara Formation, on the 1988 geologic map (Pushcharovsky et al., 1988). This volcanism cutoff date is a somewhat surprising conclusion in view of the fact that according to K-Ar dating (Iturralde-Vinent et al., 1996), the period of 65–75 m.y. (Maastrichtian) represents the highest peak of thermal activity (rock formation, metamorphism, etc.) in the Cabaiguan* sequence. At any rate, it must be pointed out that the flows of the Salvador* and Carlota* formations are basalts, quite different from the preceding, older, rhyolitic flows. The basalts suggest late-orogenic volcanic activity, which, in this study, will be considered lower Maastrichtian. Drilling. —Several wells have been drilled in the eastward continuation of the Cabaiguan* sequence. Information is available on some of them. 1) Kewanee Cabrera-1. Drilled 3 km (1.8 mi) north of the town of Seibabo, was spudded in the Bijabo*

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FIGURE 126. Western Cuba: basic igneous-volcanics terrane generalized geologic map. Formation, and encountered the Taguasco* at 3610 ft (1101 m) to total depth at 6193 ft (1888 m). 2) General Corporation Echevarria-1. Drilled approximately 5 km (3.1 mi) northeast of the town of Jatibonico, was spudded in Oligocene sediments, and penetrated undifferentiated Old Volcanics* at 1072 ft (327 m) to total depth at 8375 ft (2553 m). The producing interval is at the contact between the volcanics and the overlying Tertiary. 3) EPEP Jatibonico-78. Drilled 6.5 km (4 mi) westnorthwest of Jatibonico, was spudded in the young Tertiary cover, and is reported (in Shien et al., 1984) to have encountered Upper Cretaceous intermediate to basic tuffs, flows, and agglomerates at ±1150 ft (±350 m). At ±4725 ft (±1440 m), it penetrated Aptian–Albian intermediate to basic tuffs and flows. Below 10,030 ft (±3180 m), basic flows were penetrated to 13,775 ft (±4200 m), where pre-Mesozoic metamorphics were reported to a total depth of 14,553 ft (4437 m). The kind of metamorphics and the basis for dating the volcanics are unknown, but the succession suggests a normal Cabaiguan into Domingo section.

4) Cristales oil field. In this field, 30 km (18 mi) due east of the town of Jatibonico, the production is from the vugular reefoidal limestones of the Jiquimas* Formation (Cristales limestone) at, or under, an unspecified Tertiary unconformity over the volcanics at ±1800 ft (±550 m).

Western Cuba As in central Cuba, the basic igneous-volcanic province can be subdivided into the Domingo* sequence, consisting of ultrabasic rocks and basalts, spilites, etc., and the Cabaiguan* sequence that consists of intermediate to acid volcanics and associated sediments. In western Cuba, rocks belonging to these belts are found in three general areas (see Figure 126), all forming part of Truitt’s (1956a, b) Bahia Honda* belt: the Bahia Honda vicinity, the area south of the Pinar fault, and the north of the Isle de la Juventud. Figure 127 is a correlation chart of western Cuba, including northern Cuba. In this study, the name Bahia Honda area will be used in the geographically restricted sense of Furrazola-

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FIGURE 127. Correlation chart, basic igneous-volcanic terrane, western and northern Cuba. Bermu´dez et al. (1964) (it is considered by them as a subzone of the Zaza zone). Here, it will be subdivided into a southern tectonic unit and a northern tectonic unit. The area south of the Pinar fault is named the Los Palacios Basin, and the unmetamorphosed volcanics outcropping in the north of the Isla de la Juventud is named the Isla de la Juventud area. These areas are defined as follows. Bahia Honda Area. — The Bahia Honda area is present only in the northeastern Pinar del Rio (see Figure 128) and is the continuation of the basic igneous-volcanic province of central Cuba after outcropping through La Habana and Matanzas provinces, where it is broken up by a large number of cross-faults into relatively small segments. In western Cuba, it forms a large body of parallel, fairly coherent, elongat-

ed outcrops that extends from Manuel Sanguily eastward for 74 km (46 mi). The Bahia Honda area is found north of the Guajaibon – Sierra Azul and northern Rosario belts, east of the La Esperanza belt, and toward La Habana. After the Pinar fault disappears, it merges with the eastern Los Palacios Basin. Pszczo´lkowski and Albear (1982) and Pushcharovsky et al. (1988) subdivide the Bahia Honda area into two units: 1) Northern tectonic unit. It contains ultrabasics. It extends from the coast to the fault that defines the southern limit of the ultrabasics. 2) Southern tectonic unit. It is characterized by volcanics and volcaniclastics, with no ultrabasics,

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FIGURE 128. Western Cuba, Bahia Honda, and Los Palacios areas.

and dipping steeply northward under the northern tectonic unit. Los Palacios Basin. — This area extends along the southern side of the Pinar fault all the way to the south coast of Pinar del Rio. It is mostly a subsurface feature, except for a narrow belt of early Tertiary and Upper Cretaceous outcrops along the Pinar fault. Several wells have been drilled into it. Pszczo´lkowski (1978) used the term ‘‘San Diego de los Ban ˜ os structurofacies zone.’’ It is called Los Palacios Basin in Pushcharovsky et al. (1988). Isla de la Juventud Area. — A small area of unmetamorphosed Cretaceous volcanics exists outcropping in the northwest of the Isla de la Juventud.

Domingo* Sequence Bahia Honda Area: Northern Tectonic Unit The Domingo* sequence is represented by an association of serpentines and gabbroic rocks that occur in a continuous way only in the northern tectonic unit of the Bahia Honda area (named the Felicidades belt). Despite structural complications, like in other

areas of Cuba, it appears to be overlain by the Cabaiguan* sequence. The northern tectonic unit also overlies the southern tectonic unit, where it is in a north-dipping fault contact with the Quin ˜ ones, Encrucijada, and Via Blanca formations of the Cabaiguan* sequence. Serpentine. — It forms most of the rocks representing this belt. In the southwestern part of the northern area, they form the large mass of the Sierra de Cajalbana. They are present throughout the area in isolated patches, but form a narrow linear body that extends for the entire length and defines the southern limit of the unit. The serpentine appears to form a steeply north-dipping tabular body. As in central Cuba, the Domingo* sequence appears to represent the base of the basic igneous-volcanic section. According to Garcia-Casco et al. (2003), it seems to have been formed at moderate pressure (6–8 kbar) and moderately high temperature (6008C). Thicknesses of the serpentine are impossible to estimate, but as in central Cuba, they are very variable. The serpentines are highly disturbed and appear to be overlain by gabbroic rocks. Concerning the wildflysch (Big Boulder bed) or Vieja Member of the Manacas (Quin ˜ ones)

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Formation in contact with the serpentine, Hatten (1957) described many ‘‘exotic’’ blocks of amphibolite, actinolite garnet schists, and hornblende-quartz rocks are enclosed by the serpentinized rock. These metamorphics are of unknown origin. He might have been referring to the basal part of the serpentine body, which is chaotic in nature, and would therefore contain exotic metamorphic blocks as does the lower Domingo* sequence in the Santa Clara area of central Cuba.

Gabbros A complex consisting of spilites, gabbros, diabase, troctolite, and anorthosite is found associated with the serpentines. Although most of the contacts are modified by tectonism, this complex appears to overlie the serpentine and underlie the rocks of the Cabaiguan* sequence of the northern tectonic unit.

Other Areas Outside the Bahia Honda area, many patches of serpentine associated with faults are present throughout the Sierra de Guaniguanico. Very commonly, they are in contact with the Manacas Formation. They might be remnants of a Domingo-Cabaiguan belt thrust sheet over the Manacas Formation. Many of them are large olistoliths of Domingo* sequence in the wildflysch of the Vieja Member of the Manacas Formation. A particularly large outcrop of serpentine and gabbro, present in the Cabeza de Horacio window (surrounded by San Cayetano and associated with La Esperanza Formation), could be a remnant of Domingo* sequence caught in the thrusting, as suggested by Pardo (1975), or be an equivalent of the El Sabalo oceanic basement under the La Esperanza Formation. At any rate, it appears to be allochthonous because it has no gravity or magnetic expression.

Cabaiguan* Sequence This belt is not nearly as well developed as in central Cuba and in general is structurally much more disturbed. The section is shown in Figure 129.

Bahia Honda Area: Northern Tectonic Unit This area is shown in Figure 128. Encrucijada Formation. — This unit consists of ±2000 ft (±600 m) of massive, commonly badly weathered and highly sheared, amygdaloidal, and porphyritic basic flows and thick chert interbeds.

Occasional associated tuffs, volcanic derived shales, and sandstones occur. Occasional dirty limestones are also observed. The Encrucijada Formation is the lower part of the Chirino Formation of Pszczo´lkowski and Albear (1982). It is also part of Truitt’s (1956a, b) Nun ˜ ez Formation. This unit is considered Aptian–Albian in age and is believed to be transitional with the Orozco Formation. Orozco Formation. — The Orozco Formation is the upper part of the Chirino Formation of Pszczo´lkowski and Albear (1982). It is also part of Truitt’s (1956a, b) Nun ˜ ez Formation. This unit consists of 1600 ft (500 m) of basaltic and dacitic tuffs, basalts, tuffaceous sandstones, and conglomerates. It is considered Cenomanian–Turonian and is a noncalcareous, noncherty equivalent of the Quin ˜ ones Formation of the southern unit. It is unconformably below the Via Blanca Formation. Via Blanca Formation. — The Via Blanca Formation consists of an unknown thickness (but as much as several hundred meters) of reddish green shales, graywacke siltstones, and sandstones with a few interbeds of white marls. Conglomerates are common and consists of two types: (1) those consisting mostly of igneous material and (2) carbonate breccias with a high percentage of limestone components containing rudists (probably derived from San Juan y Martinez). This formation is mostly restricted to the northern unit and extends eastward toward La Habana, where it was originally described. It contains an abundant foraminiferal fauna (described in the section on northern Cuba) indicating a Campanian – late Maastrichtian age. In an area north of La Palma, west of the Sierra de Cajalbana, the rudist Titanosarcolites sp. has been identified. This unit was deposited under shallow- to relatively deep-water conditions, and the source of material appears to have been in the south-southwest. It is unconformably overlain by the Pen ˜alver Formation and is equivalent, and in places similar, to the San Juan y Martinez Formation of the Los Palacios Basin. Pen ˜ alver Formation. — The Pen ˜alver Formation consists of up to ±330 ft (100 m) of a dominantly carbonate turbidite bed showing graded bedding. At the base, the clasts are up to 5 ft (1.5 m) in diameter, decreasing to silt size at the top. The clasts consist mostly of rudist fragments, foraminifera (planktonic and benthonic), shallow- and deep-water limestones, and frequent terrigenous and igneous rock fragments. Bro ¨ nnimann and Rigassi (1963) originally described the Pen ˜alver Formation from the area of La Habana. It will be described in more details in the section on

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FIGURE 129. Stratigraphic section: Domingo and Cabaiguan* sequences, Bahia Honda area.

northern Cuba below in this chapter. The age is considered upper Maastrichtian and, therefore, is equivalent and lithologically similar to the Cacarajı´cara and Amaro formations (although the terrigenous material is more abundant). It rest unconformably below the Capdevila Formation. Vibora Group. —It consists of 1000 ft (300 m) of sandstones, conglomerates, shales, marls, and limestones of Paleocene age. The origin of this name is unknown, but it is shown in Pushcharovsky et al. (1988) as a grouping of formations. The formations

composing it will be described in the section on northern Cuba below in this chapter, where all the individual formations were named. The Mariel Group, consisting of the Madruga and Capdevila formations, is also used. This group comprises of the Mercedes, Apolo, Madruga, Via Crucis, and Alkazar formations that will be described in detail in the below section on northern Cuba. Capdevila Formation.—It consists of 1500–2000 ft (450–600 m) of an interbedding of polymict, graywacke sandstones, sandy calcarenites, shales, marls,

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and conglomerates. Some pebbles of leucocratic gneiss, possibly originating from an older basement, are present in the conglomerates. These sediments are typically representative of flysch conditions with characteristic turbidites in relatively deep waters. Originally named by Palmer (1934) and described in detail by Bro ¨ nnimann and Rigassi (1963) from the area of La Habana, it will be described in more detail in the section on northern Cuba. An abundant fauna of planktonic foraminifera indicates an upper Paleocene to early lower Eocene age. This unit is found in contact with several older units, indicating some transgressive relationship. It is comformably overlain by the Universidad Formation. This section correlates and shows similarities with part of the Pica Pica of the Sierra de Guaniguanico and with the Vega* and San Martin* formations of central Cuba. Universidad Formation. — The Universidad Formation consists of up to 150 ft (50 m) of white to yellowish white marls interbedded with calcarenites at the base. Occasional chert nodules are present. Volcanic glass has been identified as a detrital component. It was named by P. Bermudez in 1937 (Bermudez, 1961) and discussed in detail by Bro ¨ nnimann and Rigassi (1963) from the area of La Habana. It will be described in more detail in the below section on northern Cuba. It is sometimes called a group, including the Toledo and Principe formations. Radiolaria are abundant, as well as planktonic foraminifera. The age is considered as lower–middle Eocene. This formation is the youngest under the regional upper Eocene unconformity and, like the Rubio* Formation (FomentoTaguasco area), indicates a late-orogenic return to carbonate sedimentation.

Bahia Honda Area: Southern Tectonic Unit This area is shown in Figure 128. Encrucijada Formation.—Here, this unit is ±3000 ft (±900 m) thick. It is believed to be transitional with the Quin ˜ones Formation. The Encrucijada Formation is the lower part of the Felicidades Formation of Pszczo´lkowski and Albear (1982). It is also part of Truitt’s (1956a, b) Nun ˜ez Formation. Quin ˜ ones Formation. — This unit consists of ±2000 ft (±600 m) of interbedded sandy limestones, siltstones, shales, and cherts with an increasing percentage of shale and chert beds toward the upper part of the section. Sandstones, shales, and breccias are found at the top. The limestones contain abundant planktonic microorganisms (calcisphaerulidae) as well as terrigenous and pyroclastic material. The Quin ˜ones Formation is the upper part of the Felicidades For-

mation of Pszczo´lkowski and Albear (1982). It is also part of Truitt’s (1956a, b) Nun ˜ez Formation. The age is considered mostly Cenomanian and Turonian, although it might extend in the Campanian. This unit is in part equivalent and shows similarities to the Gomez* Formation of central Cuba and also shows some affinities with some of the Upper Cretaceous of the sedimentary belts of the Sierra de Guaniguanico. In the eastern extreme of the southern unit, it lies unconformably under the Via Blanca Formation. Via Blanca Formation. —The Via Blanca Formation occurs as a small area of outcrops in the eastern end of this tectonic unit. It consists mostly of reddish green shales, graywacke siltstones, and sandstones with a few interbeds of white marls. Bro ¨ nnimann and Rigassi (1963) originally described the Via Blanca Formation from the area of La Habana. It will be described in more detail in the below section on northern Cuba. Drilling. — EPEP Mariel-1. — A very generalized section of this well is shown in Cuba, 1985a. This well encountered the Neogene to ±820 ft (±250 m). From this point to ±5250 ft (1600 m), it penetrated volcanics and volcaniclastics of Valanginian to Santonian age. From there to ±7950 ft (2150 m), it drilled through the ultrabasics, and from that point to the total depth of 10,500 ft (3201 m), it went through Campanian– Maastrichtian breccias, limestones, and shales. Obviously, this well penetrated the Cabaiguan* and Domingo* sequences, and below, a thrust went into either a repeat of the upper Cabaiguan* sequence or into a carbonate, nonvolcanic unit. Kuznetsov et al. (1985) show an unidentified Mariel well, perhaps a composite between EPEP Mariel-1 and 2 (the total depth does not correspond with Petroconsultants, 1997, or Shien et al., 1984). This section shows that this well penetrated the Neogene to ±2200 ft (±670 m), the Campanian– Santonian volcanics and volcaniclastics to ±4130 ft (±1260 m), then the Aptian–Albian ultrabasic complex and flows to ±7950 ft (±2420 m), and finally, after going through a major thrust, into an igneous and sedimentary Maastrichtian–Paleocene megabreccia (probably the Vieja Member) to total depth at 10,825 ft (3300 m). Whatever the origin of the published section, it confirms the EPEP Mariel-1 section and show that both bottomed in a major thrust zone without conclusively reaching one of the Sierra de Guaniguanico sedimentary facies. EPEP Martin Mesa-1. —It was drilled 10 km (8 mi) east of the Mariel wells and on the northern edge of the Martin Mesa window. It reached the total depth of

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10,663 ft (3250 m) (Petroconsultants, 1997, depth), remaining within the carbonates of the Martin Mesa Group without any trace of Domingo* or Cabaiguan* sequence rocks. These wells support the fact that if the basic igneousvolcanic province has been thrusted over the carbonate belts of the Sierra del Rosario, the present attitude of the thrust is very steep and possibly cut by imbrications.

Los Palacios Basin Relatively little is publicly known about this basin. It extends for 150 km (93 mi) in a northeast – southwest direction. It is bounded on the southeast by a strong positive gravity and magnetic anomaly in the Guanal area, giving it a width of 30 km (18 mi). However, if these anomalies are intrabasinal features caused by the shallow presence of Domingo* sequence rocks (as suggested by drilling) and not related to an in-situ basement, the basin could extend to the Isle de la Juventud or a distance of 100 km (62 mi) from the Pinar fault. This area is shown in Figure 128. Only the upper part of the section is known through the exposures along the Pinar fault. Several wells have been drilled near the towns of Ariguanabo, Candelaria, and Los Palacios in an area that generally coincides with a major regional gravity low. Few results have been published, and the ones that have are rather sketchy. However, they indicate a narrow deep Tertiary basin, obviously related to the Pinar fault. Unfortunately, even the deepest wells provide little information on the pre-Tertiary section. The section, shown in Figure 130, is as follows. San Juan y Martinez Formation. —The San Juan y Martinez Formation (Herrera, 1961, named this formation) consists of a minimum of 1070 ft (325 m) of sandstones, siltstones, conglomerates, shales, marly limestones, and masses of rudist limestones. Rapid horizontal changes of lithology are typical for this formation; very few beds extend for a long distance. The most characteristic and dominant type of sediment is a bioclastic limestone with an abundant rudist fauna. The rudists are grouped in biostromes, or pseudoreefs, showing the animal shells in their upright living position. In addition to rudists, corals, algae, oysters, bryozoa, and other unidentified organisms are present. The limestones are lenticular and are transitional to clastic sediments, mainly conglomeratic lenses with boulders reaching several tens of centimeters in diameter. The conglomerate’s dominant components are andesite, trachite, basalts, and various types of tuffs. Minor components of quartz sand-

stone, quartz, and cherts occur. The base of the formation has never been observed. The rudist fauna is very rich, and some of the forms identified are as follows: Antillocaprina annulata, Antillocaprina crassitella, Bournonia aff. bournoni, Bournonia aff. africana, Chiapacella radiolitiformis, Coralliochama sp., Dichtyoptychus sp., Joufia sp., Hippurites mulleriedi, Lithocalamus colonicus, Mitrocaprina sp., Parabournonia sp., Plagioptychus tschoppi, Praebarrettia corali, Praebarrettia aff. peruviana, Prebarretia sparcilirata, Praebarrettia torrei, Sabina aff. kugleri, Tampsia rutteni, Titanosarcolites giganteus, and Titanosarcolites macgillavryi. Abundant large foraminifera are also present, including Orbitoides apiculata, Pseudorbitoides israelskyi, Pseudorbitoides kozaryi, Pseudorbitoides rutteni, Somoutina bermudezi, Sulcoperculina angulata, and Sulcoperculina diazi. The age of the formation is considered to extend from the Campanian through the Maastrichtian; it is equivalent to the Via Blanca and Pen ˜ alver formations. This formation lies unconformably under the upper Paleocene Capdevila Formation. Much of the Paleocene appears to be missing. The sediments of the San Juan y Martinez Formation were deposited in a highly variable littoral environment. All along the Pinar fault, the results of deep drilling indicate a southeastward deepening of the basin. The sediments become finer, and there is progressively less of a benthonic organism contribution toward the center of the Los Palacios Basin. Capdevila Formation.—Here, this unit exceeds 5500 ft (1680 m) in thickness. The lower part of the formation consists of sandy and argillaceous sediments with a few marl interbeds. Over these beds is an assemblage of polymict sandstones, argillite, and conglomerates that can reach 1650 ft (500 m) in thickness. The conglomerates are poorly sorted, commonly strongly bimodal with boulder size components in a siltstone matrix. Graded bedding and pebbly mudstones can be observed. The components can reach several meters in diameter (±10 ft; ±3 m), are well rounded, and consist mostly of volcanic rocks. Gneisses (possibly older basement) and carbonates are occasionally present. Some unusual components of the section are worth mentioning: tuffs and agglomerates and pink to cream bioclastic limestones with abundant algae, gastropods, pelecypods, corals, and foraminifera. The bedding between the above units is rather indistinct, and all grade into each other. The uppermost part of the section consists of sandstones, siltstones, and shales with thin interbedding

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FIGURE 130. Stratigraphic section: Cabaiguan sequence, Palacios Basin.

of marls. Graded bedding and flow structures are common. In the more complete sections, the marls become more abundant toward the top where the Capdevila grades into the overlying Universidad Formation. In other places, the Loma Candela Formation overlies it with unconformity. The Capdevila Formation contains abundant foraminifera, among them Distychoplax biserialis, Globigerina mckannai, Globorotalia pseudomenardii, Globorotalia quetra(?), Globorotalia velascoensis, Globorotalia cf. crassata densa, Globorotalia cf. aequa, Globorotalia cf. acuta,

Globorotalia cf. aragonensis, Globorotalia cf. wilcoxensis, and Nummoloculina heimi. The age is considered upper Paleocene and lower Eocene. The clastic material (volcanic) was derived from the southwest. Universidad Formation. — It is represented by a thickness not exceeding 165 ft (50 m) of thin- to medium-bedded, light-gray marls with a few interbeds of fine calcarenites, siltstones, and sandstones. It contains a rich foraminifera fauna, including Discocyclina cf. cubensis, Eoconuloides wellsi, Globigerina

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cf. mckannai, Globorotalia aragonensis, Globorotalia cf. crassata densa, and Globorotalia cf. aequa. The age is considered late lower and early middle Eocene. The Universidad Formation unconformably underlies the middle Eocene, postorogenic sediments of the Loma Candela Formation. Drilling. — As mentioned, 16 wells between 3300 and 9800 ft (1000 and 3000 m) have been drilled in this basin, but little information on them is publicly available. EPEP Candelaria-1. — The most detailed published information on the subsurface of this basin is given in a report by Ferna´ndez et al. (1987) on this well drilled by EPEP, near the town of Candelaria, to a total depth of 14,380 ft (4384 m). The section encountered is as follows. 0 ft (0 m): Consists of post– middle Eocene detritus equivalent to Loma Candela and younger units. A description of this younger section will be given below in the Post – Middle Eocene Stratigraphy. 11,676 ft (3560 m): This interval consists of polymict sandstones and siltstones, shales, fine-grained bioclastic shaly limestones, and gravels with an increasing amount of volcanic detritus. Abundant planktonic foraminifera are present, indicating a lower Eocene age. No middle Eocene faunas were found. This interval is considered to belong to the lower Capdevila Formation. 12,169 ft (3710 m): This unit is characterized as a very argillaceous, silty, bioclastic limestone with fragments of basalts and a lithocrystallovitroclastic tuff. The age is considered middle – upper Paleocene based on poorly preserved Globorotalia acuta and Globorotalia pseudomenadii. It is also considered equivalent to the lower Capdevila Formation. 12,464 ft (3800 m): Arkosic-type sandstones, siltstones, and gravels characterize the upper part of this interval. The lower part of the interval, below 13,999 ft (4268 m), is characterized by a decrease in the arkosic material and an increase in volcanic components. At total depth of 14,380 ft (4384 m), only volcanic detritus is present. The report mentions high dips throughout the interval, so not much section was penetrated. The fauna is poorly preserved, but Globotruncana sp. and other remnants of algae, bryozoa, corals, mollusks, etc. have been interpreted as indicating an Upper Cretaceous age (if such was the case, it would be equivalent to part of the San Juan y Martinez For-

mation). However, the Cretaceous fauna might be reworked, and the lithology of the upper part of the section suggests the Bacunayagua Formation of upper Paleocene age. Shien et al., 1984, show the generalized logs of two wells: ARCO Los Palacios-1A, and ESSO CUBA Guanal-1A (probably Guanal-1). ARCO Los Palacios-1. — This well bottomed at 8000 ft (2439 m) in postorogenic middle–upper Eocene clastics (therefore, not penetrating the Cabaiguan* sequence rocks). ESSO CUBA Guanal-1. — This well bottomed at 3214 ft (980 m), penetrating Coniacian–Santonian volcanics below the Neogene (there are some doubts about the accuracy of this study). H. Wassall reports (1990, personal communication) that ESSO CUBA Guanal-1 penetrated diabase or serpentine below lower Miocene (it is not known whether it is in situ or a boulder). The Guanal wells were drilled on a strong regional gravity high and sharp magnetic high-low anomaly.

Isla de la Juventud Area In the northwestern Isle de la Juventud is a group of outcrops, called the Sabana Grande zone by Milla´n (1981) (see Figure 131) and Pushcharovsky et al. (1988), limited by faults, which was mapped as the undifferentiated and unmetamorphosed Cretaceous Teneme Formation (named by Pushcharovsky [1988]; Pushcharovsky et al. [1988] also show a volcanic Teneme Formation in southeastern Oriente; it is not known if this is accidental or on purpose), consisting of andesites and basalts. Not much more can be found in the published literature, although these exposures are a clear indication that unmetamorphosed Cabaiguan* sequence volcanics are in contact with the Isle de la Juventud metamorphics, as in the Escambray massif. Within the metamorphic massif proper, masses of granitoids are present, believed related to the Cretaceous volcanics.

Western Cuba: Basic Igneous-Volcanic Terrane Discussion The basic igneous-volcanic province in western Cuba is not as well developed and thick as in central Cuba. Except for the Sierra de Cajalbana, the ultrabasics are poorly represented. Pre-Cenomanian volcanics (Encrucijada Formation) also are not as well developed as in central Cuba. The Cenomanian, as in central Cuba,

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FIGURE 131. Isla de la Juventud, Cabaiguan sequence.

represents a possible pause in volcanism, with the deposition of carbonates and nonvolcanic-derived sediments. In western Cuba, important volcanic activity seems to have ceased by the Turonian to Campanian; the Via Blanca Formation contains abundant volcanic detritus but no direct evidence of volcanic activity (flows, tuffs, breccias, etc.). This is true for the remainder of the section, although reports of tuffs exist in the lower Paleogene. Simultaneously, sediments were being carried northward into the Via Blanca and Pen ˜alver formations of the Bahia Honda area. This is supporting evidence that the Palacios Basin and the Bahia Honda area were part, at one time, of the same sheet of the basic igneous-volcanic province, which was being uplifted and eroded in the late Campanian–Maastrichtian. This uplift might have corresponded to the initial thrusting of the primarily volcanic basin (eugeosyncline) over the primarily carbonate basin (miogeosyncline). This must have happened a considerable distance away from its present position, but close enough so the volcanics and intrusive rocks could contribute fine detritus to the Campanian–Maastrichtian Moreno and Cacarajı´cara formations. The sediments of the Manacas Formation were therefore derived from the erosion and collapse, in the

late Paleocene, of an already existing incipient thrust sheet of basic igneous and volcanic rocks. Of greatest importance is the fact that the initial overriding of the sediments by the basic igneous-volcanic province could have started during the Maastrichtian or as much as 17 m.y. before the development of the nappe structures, or thrusting, that characterize the Sierra de Guaniguanico. A similar difference in timing could have occurred in central Cuba as indicated by the volcanic detritus in the Maastrichtian Amaro* Formation, preceding the lower – middle Eocene Vega Formation. The presence of arkosic sediments in the questionable Upper Cretaceous of Candelaria-1 is puzzling. It is reminiscent of the granitic boulders in the Paleocene Taguasco* Formation of central Cuba or, as will be discussed in the section on northern Cuba, of the biotitic granite boulders in the conglomerates of the Paleocene Bacunayagua Formation (part equivalent to the Capdevila). These components seem to have had a northern origin (originally suggested by Hatten et al., 1958) that, with the exception of the Rancho Veloz, Tre´s Guanos, and La Rana klippes, has mostly disappeared today. Such a situation could be very likely if a regional basement high (extensional) separated the volcanic and carbonate basins, and the

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thrusting of the basic igneous and volcanics occurred over a relatively thin sedimentary section, underlain by a mixture of granodiorite and basalts. This is suggested by the basement remnants in the northern Rosario and Cifuentes* belts. The rocks presently exposed in the core of the Guaniguanico Mountains do not show up in the sediments of the Palacios Basin until the middle – upper Eocene, which is when they were effectively eroded away. This is a very good proof of the timing of the deformation in western Cuba. It is impossible to estimate accurately the original width of this province; however, its minimum width should have been at least the distance from the coast, north of La Habana, to the Isla de la Juventud, or 150 km (93 mi). The origin of the Domingo* and Cabaiguan* sequence rocks of the Bahia Honda area has been subject to much controversy. Some authors have stated, and still maintain, that the Bahia Honda area was thrusted from the north over the Guaniguanico Mountains. Iturralde-Vinent (1996) points out that no incontrovertible evidence exists that rocks from the basic igneous-volcanic terrane are present in the Palacios Basin. The position of the reported ultrabasics penetrated by ESSO CUBA Guanal-1 is questionable, and the wells EPEP Candelaria-1 and ARCO Los Palacios-1 never reached basement and bottomed in the postvolcanic Tertiary. He proposed an origin in the Palacios Basin, with thrusting north over the Guaniguanico and south over the Isla de la Juventud. However, the well Shell Ariguanabo-1, south of the Martin-Mesa window, in what appears to be the northeast end of the Palacios Basin, drilled through 3775 ft (1150 m) of Cretaceous volcanics. They are a continuation of the Domingo and Cabaiguan sections in northern and central Cuba, showing the same relationship to the Guaniguanico Mountains as to central Cuba sediments. In addition, the presence of Cabaiguan sequence volcanics over metamorphosed southwestern terrane sediments in the Isla de la Juventud suggests that these rocks very probably originated south of the Isla de la Juventud metamorphics and were thrusted northward over them, the Palacios Basin, and the Sierra de Guaniguanico.

Northern Cuba Northern Cuba does not provide much information about the general geology, but being near the capital, it was probably studied and sampled more than any other part of the island. Most of the older

stratigraphic names, type localities, and descriptions (as well as many fossil determinations) originate from the general Habana area. As will be seen below, here, the section represents a very restricted phase of the Cuban orogeny. The lower part of the section is very fragmented; however, as the rocks become younger, the structural deformation is less intense, and as in eastern Las Villas and western Camaguey provinces, the flysch deposits of the middle Eocene extend into the upper Eocene and become almost transitional with, and indistinguishable from, the postorogenic molasse deposits. In addition, as already mentioned, many wells have been drilled in the area. Figure 132 shows the locations of the most heavily drilled areas and the outcrops of the Domingo* as well as the upper and lower Cabaiguan sequences.

Domingo*–Cabaiguan* Sequences Albear Franquiz and Iturralde-Vinent (1985a, b) include the San Adrian Formation, which was described at the beginning of this chapter (under the section on the basal section of the carbonate platform province in central Cuba) as a Cenomanian–Turonian evaporitic unit in the Cabaiguan* sequence. This is an unusual interpretation, based in part on the presence of a Cenomanian fauna found by V. Kuznetsov (personal communication to M. Iturralde-Vinent, 1975) in a shale lens within the gypsum. However, this interpretation may be caused by the desire to explain away a piece of information that does not fit some tectonic theories. The evaporite, and later the carbonate bank, were not supposed to have extended this far west. It might also be the reason why Truitt’s (1956a, b) Cacarajı´cara (Guajaibon–Sierra Azul) belt of western Cuba was also ignored for a long time. There is no question that the San Adrian diapir is not a diapir in the true sense; it is a mass of evaporite that was caught in a complex fault system and served as lubricant, incorporating a large range of exotics, including schists, marble, and serpentine, as well as Nannoconus limestones that are totally alien to the Cabaiguan* sequence. More than 50% of the total rock is composed of quartzose and micaceous clastics, also totally foreign to the Cabaiguan belt, suggesting the San Cayetano or the La Esperanza formations of western Cuba. It is likely that the San Adrian Formation is a tectonically disturbed sample of some unknown unit, close to the base of the Las Villas* belt section and totally unrelated to the Cabaiguan* sequence. The section described as follows is a composite of northern Cuba (see Figure 133).

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FIGURE 132. Northern Cuba: basic igneous-volcanic terrane generalized geologic map.

Ultrabasics. —These rocks appear to form the basement over which the Cabaiguan* sequence was deposited. The outcrops consist mostly of highly sheared (waxy) serpentine in bodies ranging from a few meters to 16 km in length. In several outcrops, bodies of gabbro or troctolite are associated with the serpentines, and are commonly found between the serpentine and the volcanics of the Cabaiguan* sequence. Chirino Formation. — This unit consists of possibly more than 3300 ft (1000 m) of the following lithologies: (1) green to grayish green tuffaceous cherts; (2) vitric and crystalline tuff; (3) reddish medium- to coarse-grained lithic tuff; (4) andesite and vesicular lava; (5) and graywacke sandstones, tuffaceous shales, and argillaceous limestones. Ducloz (1960, 1963) named this formation. It was formerly included in the Habana Formation and later in the pre-Via Blanca beds by Bro ¨ nnimann and Rigassi (1963).

Near Matanzas, where this formation is well developed, the vitrocrystalloclastic and medium-grained lithocrystalloclastic tuffs with lapillis predominate. They sometimes form massive, well-bedded sequences; dark-brown or green color predominates. They are interbedded with tuffs, limestones, cherts, andesite, and basalts. The limestones have light colors, gray to pinkish cream, fine to medium grained, well bedded to laminated, and associated with beds or nodules of green, violet, white, or black chert. The andesites and basalts commonly have pillows. Radiolaria are abundant, but other fossils are very rare. In a sandstone interbedded with this sequence, the following microfossils were found: Hedbergella sp., Pithonella trejoi, Pithonella ovalis, and Stomiosphaera sphaerica, indicating an Albian–Cenomanian age. The contacts with other units are tectonic, but the general impression is that the Chirino Formation overlies the gabbros of the Domingo* sequence and underlies the

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FIGURE 133. Stratigraphic section: Domingo-Cabaiguan* sequences northern Cuba, surface sections.

La Trampa Group, which has been dated as probable Cenomanian–Turonian. La Trampa Group.— This unit consists of more than 1000 ft (300 m) of medium-bedded tuffaceous, gravel-size conglomerates, with components of coarsegrained marbles, andesites, diorites, and porphyries.

The matrix consists of coarse-grained tuffaceous sandstone, and the cement can be calcareous. These conglomerates are interbedded with tuffaceous shales, containing radiolaria, and coarse-grained, dark-purple, graywacke sandstones, also with calcareous cement. Interbeds of whitish chloritized andesite-dacite lavas

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and coarse-grained, chloritized, lithoclastic tuffs are also present. In the graywacke are some quartz and serpentinite grains. This name was used by Kozary (1955a, b) to describe a massive trachiandesite porphyry. The name was extended to associated sediments by Albear Franquiz and Iturralde-Vinent (1985a). It was formerly related to the Chirino and, therefore, included in the Habana Formation. It is unknown why it is called a group because it is not subdivided. A fauna of Pithonella sp., Calcisphaerula spp., Stiomosphaera spherica, Ticinella sp., Rotalipora sp., Clavihedbergella subdigitata, Globigerinelloides cf. escheri, Heterohelix cf. globulosa, Schackoina cf. cenomana, Globotruncana sp., mollusks, and radiolaria indicates a Cenomanian–Turonian age. The Trampa Group is unconformably overlain by the Via Blanca Formation, as indicated by the presence of distinctive Trampa fragments in the Via Blanca conglomerates. It should be noted that it is the oldest formation in Cuba to contain serpentinite detritus. Via Blanca Formation. —It consists of an unknown thickness, but probably several hundred meters, of reddish green and pink shale, siltstones, and sandstones of graywacke composition, interbedded with thin beds of white marl. Bro ¨ nnimann and Rigassi (1963) named this unit. It was formerly known as part of Palmer’s Habana Formation. It is a complex unit needing more detailed studies. Several informally designated levels of conglomerate, flysch, and one olistostrome are present. Only the formal Bacuranao Member has been established. Structural complexities make it difficult to unravel the stratigraphic relationships between the different lithologies. Bacuranao Member.— This consists of some 65 ft (20 m) of yellowish to whitish gray calcareous siltstones, containing grains of igneous rocks, grading upward into calcareous marls and clays. Albear Franquiz and Iturralde-Vinent (1985a) formalized the name. It was previously named the ‘‘Bacuranao limestones’’ by Bro ¨ nnimann and Rigassi (1963). It contains abundant Campanian nannofossils and foraminifera. This unit is extensive east of Habana. Bahia Conglomerate. — The Bahia conglomerate forms a local basal conglomerate, containing clasts of limestone, graywacke sandstones and siltstones, radiolarites, peridotite and serpentinized gabbro, andesite porphyry, agglomerates, tuffs, etc. The clasts are normally 1.5 – 2.5 in. (4 – 6 cm) but can reach 3 ft (1 m). The matrix consists of coarse-grained graywacke sandstone. Some of the components have a Campanian fauna. The conglomerates are associated with thin beds of purplish red bentonitic shales and white

tuffs. This conglomerate unconformably overlies the La Trampa Formation. Via Tu´nel Conglomerate.—Most of the components consist of rudist casts and fragmental limestones; the igneous components are rare. The matrix consists of pink clay, pink graywacke sandstones, and siltstones with graded bedding and detrital limestones. The age is considered lower Maastrichtian. Casa-Escuela Conglomerate. — This unit contains clasts of limestones, graywacke, marls, and andesites. In some strata, the igneous components dominate, whereas in others, limestones dominate. The matrix consists of pinkish clay and graywacke sandstones. The youngest fragments and the matrix are Maastrichtian. Rio Piedras Conglomerate. — Contains fragments of Cenomanian–Turonian limestones, graywacke, Campanian limestones, and igneous rocks in a graywacke matrix containing Campanian faunas. Los Mangos Flysch.—This consists of an up to 330-ft (100-m)-thick, yellowish pink graywacke sandstone to clay bed with graded bedding showing coarse grains with large foraminifera at the base, and fine grains with planktonic forms at the top. Jibacoa Olistostrome.—The Jibacoa olistostrome consists of up to 330 ft (100 m) of a poorly bedded, dark-red, argillaceous siltstone matrix in which blocks ranging from a few centimeters to hundreds of meters in size are embedded. The matrix contains micas, plagioclase, magnetite, and other dark minerals as well as planktonic foraminifera that indicate a Maastrichtian age. The smaller blocks, up to 15 ft (5 m) in diameter, consist of a very weathered diorite and strongly folded Los Mangos flysch. In places, this olistostrome is found interbedded with the Los Mangos flysch. Bro ¨ nnimann and Rigassi (1963) include tuffs and andesites in the Via Blanca Formation. Albear Franquiz and Iturralde-Vinent (1985a, b), who are convinced that all volcanic activity of the Cretaceous arc ceased before the Maastrichtian (see the above discussion in this chapter on central Cuba), question this assignment. I do not see why volcanic activity should cease before gravitational tectonic movement occurs; both are certainly happening simultaneously today in many places in the world (Lesser Antilles, Java-Sumatra, Japan Trench, etc.), and in eastern Cuba, the serpentine was thrusted over the volcanics in the Maastrichtian, before the intense Paleocene–middle Eocene volcanic activity represented by the Cobre Formation. In some wells, as much as 3950 ft (1200 m) of the Via Blanca Formation have been penetrated; however, this does not consider the possible structural complications and repeats.

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The indigenous microfauna contains Pithonella ovalis, Calcisphaerula innominata, Globotruncana fornicata, Globotruncana stuarti, Globotruncana linneiana, Globotruncana lapparenti, Globotruncana mariel, Globotruncana tricarinata, Globotruncana arca, Globotruncana gansseri, Rugoglobigerina rugosa, Pseudotextularia elegans, Pseudoguembelina excolata, Pseudoguembelina striaca, Planoglobulina glabrata, Gublerina ornatissima, Gublerina arcuta robusta, Heterohelix pulchra, Heterohelix globulosa, Heterohelix carinata, and Orbitocyclina minima. The age is considered Campanian–late Maastrichtian. The Via Blanca Formation was deposited in waters deeper than 2000 ft (300 m), surrounding a volcanic terrane with abundant shallow-water reefs and banks. The sedimentation was dominantly turbiditic with collapses and slides. The Los Mangos flysch forms most of the sediment fill of the basin, and the sedimentation is believed to have been from south to north. The Pen ˜ alver Formation unconformably covers it. Bacunayagua Formation. — At the type locality, the unit (named by Ducloz, 1960) consists of 260 ft (80 m) of poorly bedded and poorly sorted gray arkosic sandstones and gravels. The size of the components ranges from a few millimeters up to 4 in. (10 cm); the larger ones are well rounded. In the clasts, light-colored minerals dominate, and marble, diorites, plagioclase, biotite, granite, quartzite, finegrained quartzose sandstones, cherts, etc., are common. This is considered a good lithologic marker in the subsurface where it is named Arena A. This generally poorly fossiliferous unit had been considered Lower Cretaceous to lower Eocene by various authors. Presently, based on the presence of Globotruncana cf. linneiana, Pseudorbitoides sp., Sulcoperculina sp., Ophtalmidium sp., and Stomiosphaera sphaerica, it is considered Campanian – Maastrichtian (Pushcharovsky et al., 1988). The rounding of the coarser components indicates that they were subject to active abrasion by streams before being dumped into deep waters without much wave erosion or chemical weathering. This is supported by the scarcity of benthonic faunas. The source of arkosic clastics has disappeared since. Pen ˜ alver Formation. — The unit consists of a 65 – 500 ft (20– 150 m) bed of limestone, bluish gray when fresh, whitish when weathered, dominantly detrital, and showing graded bedding. The lower part is coarse (rudite up to 5 cm [2 in.]) and massive, whereas the upper part is very fine (siltite) and bedded. Most of the components are made of biogenic lime-

stones, but some minor amount of igneous grains is present. Bro ¨ nnimann and Rigassi (1963) named this unit, although the name had previously been used by Kozary (1955a, b) to designate some volcanic outcrops in north central Habana. A fauna, considered indigenous, is characterized by Globotruncana stuarti, Globotruncana linneiana, Globotruncana lapparenti, Globotruncana arca, Globotruncana contusa, Pseudotextularia elegans, Omphalocyclus macroporus, Vaughanina cubana, Asterorbis macei, Asterorbis cubensis, and Kathia jamaicensis and indicates an upper Maastrichtian age. This formation, which is lithologically similar to the Cacarajı´cara and Amaro* formations, would be coeval with them and be part of an extensive deep-water turbidite deposit originating from the slumping of shallow-water carbonate banks possibly to the north and south of the basin. It is unconformably overlain by the Apolo Formation and is believed to underlie the Mercedes Formation; however, this last contact has not been observed. It is believed to represent the K/T boundary. Vibora Group.— It consists of ±1000 ft (±300 m) of sandstones, conglomerates, shales, marls, and limestones of Paleocene age. This group comprises the Mercedes, Apolo, Alkazar, Via Crucis, Madruga, and Bacunayagua formations. Mercedes Formation.—The unit (named by FurrazolaBermudez et al., 1976, from the well Shell Mercedes-2 in Matanzas Province) consists of ±330 ft (±100 m) of interbedded light-colored limestones, sandy limestones, marly limestones, calcarenites, marls, greenish gray shales, and conglomerates. The conglomerates contain clasts of limestone, sandstones, and volcanics. This unit was first described in the subsurface and later found in outcrops. Its foraminiferal fauna is characterized by Globorotalia cf. varianta, Globorotalia cf. perclara, Globorotalia pseudobulloides, Globorotalia compressa, Globorotalia trinidadensis, Globigerina triloculinoides, Globorotalia cf. imitata, and Globoconusa cf. daubjergensis. Ostracods and radiolaria are also present. The sandstones contain reworked specimens of Vaughanina cubensis, Pseudorbitoides rutteni, and Lepidorbitoides cf. floridensis, as well as benthonic foraminifera, mollusks, and algal fragments. It is considered lower Paleocene (Danian). As already mentioned under the above section on central Cuba, note that very few well-established identifications of lower Paleocene strata exist in Cuba. This unit is a flysch deposited in moderately deep waters, and it is well developed in the Jibacoa and Mariel areas. An equivalent can be recognized in the Batabano area.

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Apolo Formation. — The unit (named by Bro ¨ nnimann and Rigassi, 1963) consists of up to 330 ft (100 m) of an interbedding of deep-purple to red clay shale and siltstones, purple to greenish gray graywacke sandstones, and yellowish white to ocher calcarenites and nodular marls. This formation unconformably overlies the Pen ˜ alver and other older formations. It is conformably under the Alkazar Formation. The fauna is characterized by Amphistegina lopeztrigoi, Discocyclina anconensis, Discocyclina barkeri, Globigerina primitiva, Globigerina pseudobulloides, Globigerina soldadoensis, Subbotina triloculinoides, Globorotalia aequa, Globorotalia pseudobulloides, Globorotalia uncinata, and Morozovella angulata, indicating an middle Paleocene age. The Apolo Formation is considered to be a flysch deposited in deep water and is found only in the Jibacoa Area. Alkazar Formation. — The unit (named by Bro ¨ nnimann and Rigassi, 1963) consists of 30 – 160 ft (10 – 50 m) of interbedded greenish marls and light-colored and well-cemented, occasionally silicified, detrital limestones. It is transitional with and partially equivalent to the overlying Capdevila Formation. The fauna is very rich and characterized by Amphistegina lopeztrigoi, Discocyclina barkeri, Eoconuloides wellsi, Globigerina primitiva, Globigerina soldadoensis, Subbotina triloculinoides, Globorotalia velascoensis, Globorotalia albeari, and Globorotalia elongata, indicating an upper Paleocene age. It should be noted that the benthonic fauna is found at the base of the graded beds, and the planktonics are found in the upper fine fraction. The possibility that the entire assemblage is reworked and that the Alkazar Formation is younger than upper Paleocene exists. This unit is a flysch deposited by turbidites in deep water and outcrops in the Mariel and Jibacoa areas. Via Crucis Formation. —The Via Crucis Formation (named by Albear Franquiz and Iturralde-Vinent, 1985a) consists of up to 650 ft (200 m) of interbedded light-purple, yellowish, whitish, greenish gray, and brown siltstones, shaly siltstones, polymict sandstones, and rare conglomerates. The sequence shows rhythmic and graded bedding varying from laminae to layers a few millimeters thick. A great number of reworked fossils exist including rudists; however, planktonic foraminifera such as Subbotina triloculinoides, Globoconusa cf. daubjergensis, Globorotalia aequa, Globorotalia angulata, Globorotalia compressa, and Globorotalia cf. pseudomenardii are present, indicating an upper Paleocene age.

This formation is commonly found lying unconformably over the Cretaceous and under the Universidad Formation. It is considered to be a flysch deposit in deep waters and is found in the Jibacoa area only. Madruga Formation. — The unit (named by Lewis, 1932, who considered it Cretaceous; Bermudez, 1950, properly assigned it to the Paleogene) consists of an estimated less than 300 ft (100 m) of purple to reddish brown graywacke sandstones, siltstones, and shales interbedded with a few polymict conglomerates. The clasts in the conglomerates range from 1 to 6 ft (0.3 to 2 m) of Cretaceous sedimentary and volcanic rocks. In the indigenous fauna, Globanomalina cf. wilcoxensis, Subbotina triloculinoides, Globigerina velascoensis, Globorotalia albeari, Globorotalia pseudomenardii, Globorotalia velascoensis, and Globorotalia wilcoxensis acuta have been identified, suggesting an upper Paleocene age. It is equivalent to the Apolo and Alkazar formations and is unconformably overlain by the Universidad Formation. It is also considered to be a flysch deposited in deep waters and is present in the Jibacoa area. Equivalent units can be recognized in the Mariel and Batabano areas. Capdevila Formation. — The unit (named by Palmer, 1934) consists of an estimated 1000–1300 ft (300–400 m) of the following lithologies: 1) Light-yellow to pink, well-bedded shales, marls, graywacke sandstone, and siltstones with graded bedding. Interbeds of radiolarites with coccoliths are present. 2) Pinkish yellow to orange, graywacke sandstones and siltstones. The shales have rhythmic and graded bedding. Some microconglomerates are present. 3) Pink to pinkish orange, graywacke sandstones and conglomerates with rhythmic and graded bedding. 4) White, yellow, to pinkish-orange chalky marls and claystones. They show rhythmic and graded bedding. Occasionally, blocks of Pen ˜alver, Alcazar, etc., formations are embedded in the Capdevila Formation. They could either be olistoliths or structural imbrications. An abundant radiolaria and foraminiferal fauna contain, among others, Globorotalia rex, Globorotalia formosa, Globorotalia wilcoxensis, Globorotalia quetra, Globorotalia brodermani, Globorotalia pseudoscitula,

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Globorotalia aragonensis, Eoconuloides wellsi, Dictyoconus cookei, and Eofabiana cushmani. These indicate a lower Eocene age (Bermudez, 1950; Bro ¨ nnimann and Rigassi, 1963). However, recently, the species Globorotalia velascoensis, Subbotina triloculinoides, Globorotalia pseudomenardii, Globorotalia margidentata, and Globorotalia angulata have been found, suggesting that the formation extends down into the upper Paleocene (Albear Franquiz and Iturralde-Vinent, 1985a). This unit represents flysch sedimentation in a deepwater environment. It is equivalent to the Vega* Formation of central Cuba and the Manacas (Pica Pica) Formation of western Cuba. Universidad Formation. — This unit consists of more than 160 ft (50 m) of dominantly carbonate rocks that have been subdivided into two mappable members by Bro ¨ nnimann and Rigassi (1963). Principe member.—It consists of white to yellowish, massive marls that range from argillaceous limestones to calcareous clays. Some calcareous olistoliths are present at the base. Toledo member. — It consists of white to greenish or grayish, more or less laminated, argillaceous limestones or chalky limestones interbedded with layers containing chert nodules. In addition, silicified white to yellowish limestones are present. Altered volcanic glass is also present. Radiolaria are abundant. This member is dominant. It contains a rich foraminiferal fauna with Discocyclina cf. cubensis, Eoconuloides wellsi, Globigerina cf. mckannai, Globorotalia aragonensis, Globorotalia cf. crassata densa, and Globorotalia cf. aequa. The age is considered lower and middle Eocene. The Universidad Formation was deposited in open deep waters, and it consists almost entirely of calcareous nannoplankton with foraminifera and radiolaria and some contribution of volcanic ash. It is present in the Mariel and Jibacoa areas, where it is unconformably overlain by the middle – upper Eocene Punta Brava Formation and Urria beds. It is a partial equivalent to the Nazareno Group in the Batabano area and correlates with and is similar to the Rubio* Formation of central Cuba (Fomento-Taguasco area). Urria Beds. —This name has been given to some small channel fills, 20 ft (6 m) wide by 6–10 ft (2–3 m) deep, in the Universidad, Apolo, and Alkazar formations. They consist of white and yellowish, thin- and well-bedded, hard, microcrystalline, sometimes dolomitized limestones. The fauna consists of Globonomalina micra, Globonomalina wilcoxensis, Acerinina densa, Globigerapsis

kugleri, and Globigerina sp., indicating a middle Eocene age. These channels are the result of an intra –middle Eocene unconformity and are believed to belong to the postorogenic cycle. In western Cuba, the Universidad Formation is considered to be the uppermost unit below the major upper Eocene unconformity that indicates the end of the orogeny; however, in northern Cuba, two lithologic units are present that seem to extend uninterruptedly from the middle into the upper Eocene. These are the Nazareno Group that overlies the Capdevila and is in part equivalent to the Universidad Formation, and the Punta Brava Formation, also overlying the Capdevila, and originally thought to be restricted to the upper Eocene. These two units are described below. Nazareno group. — This consists of an estimated ±2300 ft (±700 m) of an interbedding of gray argillaceous marls, fine-grained argillaceous limestones, a few pink to reddish brown, laminated siltstones to fine-grained sandstones, and gray shales. Quartz, plagioclase, mica, and dark minerals are the dominant components of the siltstones and sandstones. The percentage of the components varies from section to section, but the limestones and the limestone-siltstoneshale sequences dominate. This unit was named by Albear Franquiz and Iturralde-Vinent (1985a), who called it a group because of its lithologic diversity and who believed that it could be broken into formations. This unit is intensely folded and faulted, so the true thickness is difficult to estimate; some wells have penetrated up to 3300 ft (1000 m) of similar Eocene sediments. Paleontologically, this formation can be subdivided into two parts, although the division is not always consistent: 1) a lower –middle Eocene part characterized by Globigerina turgida, Globigerina senni, Globigerina linaperta, Globigerina soldadoensis, Globorotalia aragonensis, Globorotalia formosa gracilis, Globigerina densa, Globigerina palmarea, Globigerina equa, Globorotalia quetra, Globigerina pseudopilensis, Globonomalina micra, Eoconuloides wellsi, Nummulites floridensis, Dictyoconus sp., Pseudophragmina sp., Distychoplax biserialis, Kainoconus ovalis, Discoaster lodoensis, Discoaster barbadensis, and radiolaria 2) an upper Eocene part containing Globigerina rohri, Globigerina linaparta, Globigerina venezuelana, Globigerina pseudoampliapertura, Globigerina trilocularia, Catapsydrax dissimilis, Globigerinatheka barri, Globigerapsis semiinvoluta, Globorotalia centralis, Kainoconus ovalis, ostracods, radiolaria, and nannoplankton

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This unit constitutes a flysch containing igneous detritus, deposited in deep water, and is in part equivalent to the dominantly calcareous Universidad Formation. It overlies unconformably the Capdevila Formation and is restricted to the southern Batabano area. The Oligocene Tinguaro Formation unconformably covers it. Punta Brava Formation. — The unit (named by Bro ¨ nnimann and Rigassi, 1963) consists of an estimated maximum of ±650 ft (±200 m) of well-bedded, yellowish cream to whitish, chalky limestones and gray to orange fine, argillaceous calcarenites with graded bedding and containing dark igneous grains. Some limestone breccias are present. Paleontologically, this formation can be subdivided into two parts: 1) a lower–middle Eocene part containing Globigerapsis kugleri, Globigerinatheka barri, Truncatulinoides cf. rhori, Acarinina pseudotopilensis, Globorotalia aragonensis, Globorotalia lehneri, Globorotalia cf. spinulosa, and Globorotalia cf. bullbrooki 2) an upper Eocene part with Hantkenina alabamensis, Hantkenina thalmanni, Hantkenina brevispira, Globorotalia centralis, Globorotalia cerroazulensis, Globorotalia altispiroides, Globigerapsis index, Globigerapsis semiinvoluta, Chiloguembelina cubensis, Globigerina ampliapertura, Globigerina pseudoampliapertura, Globigerina turritilina, Globigerina tripartia, Globigerina linaperta, Globigerina rohri, Globigerina venezuelana, Catapsydrax dissimilis, Globanomalina mitra, Cribohantkenina inflata, Globigerinita pera, Globigerinita cf. africana, Discoaster aster, Bavarudosphaera bigelowi, Bavarudosphaera discula, Tremalithus eopelagicus, and Thoracosphaera spp. This unit is in part equivalent to and has similarities with the Nazareno Group, although it contains less igneous-derived material. However, the possibility of reworking of lower–middle Eocene faunas into the upper Eocene should not be completely discarded. The Punta Brava Formation was also deposited in deep waters and is present in the Mariel area, where it unconformably overlies the Capdevila Formation. Drilling. — Many hundreds of wells have been drilled in northern Cuba from Mariel to Cardenas Bay. It is has been and is the area of greatest oil exploration and development activity and, therefore, deserves a special section. Very little has been published about the drilling results, and what has been published is, unfortunately, not very informative, especially regarding the stratigraphy of the Domingo* and Cabaiguan*

sequences. One of the most recent articles on the subject, Kuznetsov et al. (1985), provides much of the following information. As mentioned before, the EPEP geologists seldom refer to the accepted stratigraphic nomenclature and identify part of this section as ‘‘Upper Cretaceous Campanian – Maastrichtian allochthonous eugeosyncline’’ or other similar interpretive terms; however, comments and details permit some fairly safe guesses as to the relationship with the more formal, accepted nomenclature. As already mentioned, several of the deep wells along the north coast drilled through some part of the Domingo*–Cabaiguan* sequence and bottomed in the structurally underlying Martin Mesa, Las Villas*, or Cifuentes* belts, whereas the ones drilled farther south such as Shell Ariguanabo-2 and EPEP Vegas-1 never get out of the basic igneous and volcanics, even at 16,500 ft (5000 m). Some of the typical drilling results are listed below (see Figure 132 for locations). Bacuranao-Cruz Verde Oil Field. — This was drilled into and produces from fractured serpentine (Domingo* sequence). The deepest well was drilled to 7665 ft (2336 m) and encountered conglomerates and sandstones below the serpentine (Manacas Formation?). Santa Maria del Mar Oil Field. —This well produces from fractured serpentine (Domingo* sequence) and vugular dolomite (ophicalcite?) at 2200 ft (670 m). The serpentine is overlain by 1065 ft (325 m) of Maastrichtian volcanics and clastics possibly belonging to the Via Blanca and older formations (Cabaiguan* sequence). These, in turn, are overlain by 350 ft (105 m) of lower–middle Eocene and younger Tertiary. Shell Ariguanabo-2. — It was drilled 31 km (19 mi) south-southwest of La Habana by the Compania Petrolera la Estrella de Cuba (Shell) in the 1950s. It is reported to have penetrated the Campanian – Maastrichtian Via Blanca at ±2475 ft (±760 m) and the Cretaceous volcanics at ±3775 ft (±1150 m) to the total depth of 10,030 ft (3058 m). EPEP Vegas-1. —It was drilled 28 km (17 mi) southsoutheast of Jaruco by EPEP. It is reported to have spudded in the Miocene Guines Formation, immediately penetrated into the middle Eocene Nazareno Group (Cabaiguan belt), reached the Campanian – Maastrichtian Via Blanca Formation at ±8036 ft (±2450 m), and the Cretaceous volcanics at ±9840 ft (±3000 m) to the total depth of 16,498 ft (5030 m).

Domingo*–Cabaiguan* Sequence Discussion Northern Cuba, as in western Cuba, does not provide much information on the Domingo* and the

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older Cabaiguan* sequence rocks, but is quite informative on the uppermost Cretaceous and lower Paleogene (Figure 133). Here, as elsewhere in Cuba, the serpentines appear to be overlain by gabbroic rocks, and these, in turn, are overlain by volcanics. In view of the extreme structural complications, it is not certain if Lower Cretaceous volcanics are present. Perhaps these are represented by parts of the Chirino Formation in which both andesites and basalts are present. However, the presence of limestones and cherts, as well as the few fossils, suggests that parts of the Chirino are probably Albian or younger. It is possible that the Chirino limestones are in part equivalent to those of the Quin ˜ones Formation in the southern tectonic unit of the Bahia Honda area of western Cuba. They could also be equivalent to those of the Gomez* Formation in central Cuba. The La Trampa Group is a dominantly coarse clastic unit, also of Cenomanian–Turonian age, and is associated with andesites and tuffs. It is therefore impossible to establish if in northern Cuba there was a break in volcanism as in central Cuba, with a change from basic to more acid volcanics. 1) Campanian – lower Maastrichtian. The major break appears to be at the base of the Via Blanca Formation, and Bro ¨ nnimann and Rigassi (1963) recognized it. This formation consists mostly of conglomerates, olistostromes, and flysch (Los Mangos) and appears to have been deposited in deep waters surrounded by a complex topography with abundant shallow-water reefs. It represents a tectonically active period. The source of sediments seems to have been to the south. Some tuffaceous beds could be present. 2) Upper Maastrichtian. The upper Maastrichtian is characterized by the Pen ˜alver Formation, consisting of a massive carbonate turbidite with subordinate igneous detritus. Most of the components originate from carbonate banks and reefs. A strong unconformity exists at the base. If it is Maastrichtian, it would be a Cabaiguan* sequence unit similar and equivalent to the Cacarajı´cara and Amaro* formations of the carbonate belts and equivalent to the Isabel* Jiquimas* or Jimaguayu formations of central Cuba, although these last three have a more reefoidal character. 3) Lower Paleocene (Danian). This interval of time has been definitely recognized recently (1972 – 1973) only in northern Cuba, where it is represented by the relatively thin calcareous and clastic Mercedes Formation. The recognition of lower

Paleocene faunas in this formation indicates that this interval of time is generally poorly recorded in the sediments and, much like the Coniacian – Santonian, represents a hiatus over most of Cuba. The general absence of lower Paleocene is real and not a paleontological artifact, as has been suggested. 4) Upper Paleocene –middle Eocene. This interval of time is characterized by continuous basic igneousand volcanic-derived flysch deposition in deep waters, in what appears to be several relatively independent depocenters, as one would expect on a complex submarine topography. This is indicated by the variations between units that make up the Vibora Group and Capdevila Formation. The Bacunayagua Formation is considered quite significant because of its arkosic composition, similarity to the Taguasco* Formation and some arkosic sediments in the Palacios Basin of western Cuba, and its possible northern source of detritus. Most of the other flysch units seem to have been derived from the south. 5) Middle – upper Eocene. Much of the sedimentation during this period of time consisted of accumulation of foraminifera and radiolaria with a relatively small contribution of terrigenous material and volcanic ash. In many places, a marked unconformity exists between the middle and upper Eocene. In others, there appears to be continuous deposition into the upper Eocene, as indicated by the Nazareno Group and the Punta Brava Formation. Continuous sedimentation seems characteristic of the back of the basin and the tendency toward the development of pelagic carbonates in the middle Eocene, accompanied by a decrease in the amplitude of the pre –upper Eocene unconformity, as was also observed in the Fomento-Taguasco area of central Cuba (Rubio* Formation).

Eastern Cuba Eastern Cuba comprises most of the old province of Oriente, and for the purpose of this description, the pre – upper Eocene has been subdivided into the major northern Oriente, southeastern Oriente, and southwestern Oriente regions. It is worth noting that much of the early activity by geologists in Oriente was related to metallic mineral exploration (manganese and chrome). Most of the outcrops consist of volcanic and basic to ultrabasic igneous rocks, with only small and restricted outcrops of the carbonate sedimentary belts that are exposed in many other places of the island. In addition, unquestionable petroleum indications are

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FIGURE 134. Eastern Cuba: basic igneous-volcanic terrane generalized geologic map.

rare. For this reason, and except for a few reconnaissance trips, oil company geologists stayed away from Oriente. Among some of the early workers, Taber (1934), Woodring and Daviess (1944), and Lewis (1932) should be mentioned. In the mid-1940s, Hermes (1945) and De Vletter (1946), from the University of Utrech, did reconnaissance in Oriente as part of Rutten’s Cuba project. Gulf Oil did not do any work in Oriente. In the early 1950s, Myron Kozary, a Columbia University graduate student with funding from the National Science Foundation and an informal arrangement with Gulf Oil, studied and mapped a large part of northern Oriente in the vicinity of Gibara as a subject for his ph.D. thesis (Kozary, 1968). In the late 1950s, some oil exploration activity occurred, including drilling, in the Tertiary of the Cauto Basin and the Gulf of Guanacayabo, with negative results. After the 1959 revolution, a Cuban-Hungarian brigade was organized by the Institute of Geology and Paleontology of the Cuban Academy of Sciences to prepare the 1:250,000 map of Oriente, and the results of the survey are summarized in the book Contribution to the Geology of Eastern Cuba by Nagy et al. (1983). This section will rely heavily on this publication. Nagy (1983) subdivided eastern Cuba into several facies-structural zones; they appear to be most-

ly physiographic in nature, corresponding well to the above-mentioned regions, and do not necessarily fit the definition of belts. They are as follows: Remedios and Auras zone: northern Oriente region Sierras de Nipe – Cristal –Baracoa zone: southeastern Oriente region Caiman zone: southwestern Oriente region The already described carbonate platform province is named Remedios and occurs only in the northern Oriente region. Nagy names a Tunas zone, which corresponds to the eastern end in the Oriente province of the already described Cabaiguan* and Manicaragua sections, central Camaguey area of central Cuba; it will therefore not be discussed in this chapter. The metamorphic province consists of the Sierra del Purial and a relatively small area called the Asuncion area that are included in the Sierras de Nipe–Cristal– Baracoa zone. The other zone names will be mentioned when pertinent, but for the sake of uniformity, the names of belts, as used in the rest of the study, will be used (see Figure 134). Figure 135 shows a correlation chart for Oriente. In view of the markedly different geologic character of the eastern Cuba areas, these will be described separately.

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FIGURE 135. Correlation chart, basic igneous-volcanic terrane, eastern Cuba.

Northern Oriente The basic igneous-volcanic province rocks partially wrap around the carbonate platform. To the west, the strike is northwest –southeast turning northeast – southwest and pointing out to sea toward the Bahamas. This province consists of alternating bands of ultrabasics and volcanics with inclusions of carbonates. The dips are very steep, nearly vertical, and generally southward. The appearance is that of a compressed stack of northward-directed, thin thrust sheets of basic igneous and volcanic rocks with intervening outcrops of lower–middle Eocene flysch and chaotic rocks. Northern Oriente contrasts strongly with southeastern Oriente (that shows relatively flat-lying sheets of ultrabasic rocks over volcanics) and southwestern Oriente (where most of the section is made of Paleocene to middle Eocene volcanics).

The basic igneous-volcanic province is so structurally complex that estimates of section thickness and relationships are practically impossible. It is essentially a melange with nonmetamorphosed rocks, which, therefore, were not buried at a great depth. Kozary (1968) called this area the collapsed ‘‘Auras Trench.’’ Of interest is the absence of the Manicaragua* belt granodiorite and associated metamorphism. Another interesting characteristic is the inclusion of large blocks of unmetamorphosed Upper Cretaceous fossiliferous limestones into the ultrabasics with no other associated sediments; this occurrence has not been observed in any other areas. This province extends for 110 km (68 mi) from Va´squez, through Holguin, to Punta Caleta Honda (see Figure 134). Approximately half of its surface is covered by outcrops of the Domingo* sequence ultrabasics.

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FIGURE 136. Stratigraphic section: Domingo*-Cabaiguan* sequences, eastern Cuba, northern Oriente.

In view of the structural complications, these cannot be areally separated from the Cabaiguan* section.

Domingo* Sequence This section will be described separately from the Cabaiguan* sequence. It is represented by a large num-

ber of south-dipping slices of ultrabasics separated from each other by slices or blocks of Cabaiguan* sequence lithologies. Thicknesses are impossible to measure, and those shown in Figure 136 are only for illustrative purposes. Peridotite, harzburgite (serpentine).—Most of the ultrabasics consist of slightly serpentinized peridotite

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and harzburgite, with small amounts of anorthosite. The minerals are coarse grained with some amphibole crystals reaching 3 in. (7 cm) in diameter. Every grade of serpentinization can be recognized, particularly along internally sheared areas. Bands of coherent lithology, 100–150 ft (30–50 m) wide, can be observed aligned along the main structural trend that appear to form a stack of separate bodies. The degree of serpentinization is inversely proportional to the size of the ultramafic bodies. The ultramafic bodies dip steeply to the south, and serpentinization is most intense in the bottom part of the section. The ultrabasics appear to grade transitionally into gabbros at the top of the section. Metamorphic exotics are present within the ultrabasics. An 800-ft (250-m)-long block of metagranodioritic orthogneiss has been dated by the K-Ar method; a concentrate of muscovite gave 196 Ma, and one of feldspars gave 91 Ma. A biotite concentrate from another orthogneiss gave 447 Ma. Other exotics such as a carbonate graphitic phyllite and a white marble are present that Kozary (1968) considered as possible preCretaceous age. Gabbros.— Hard, unweathered gabbro is consistently associated with the ultrabasics and appears to be a product of differentiation. When internal lineation is observed, the gabbros and ultrabasics are always conformable. In the larger ultramafic bodies, the gabbros are present at the top of the south-dipping section. Cumbre*(?) Formation.— Several beds of serpentine have been identified that show faint traces of pillowlike structures with variolitic cavities, suggesting highly basic submarine lava flows. This type of feature is similar to some of the lithologies encountered in the Cumbre* Formation of central Cuba. Kozary (1968) called these beds ‘‘magmatic extrusive serpentine.’’ Sheeted dikes. —Along the southern margin of the Domingo* sequence, the 1988 geologic map (Pushcharovsky et al., 1988) shows a complex of sheeted dikes.

Cabaiguan* Sequence The lithologies of this section are present in generally vertical to steeply south-dipping slices, alternating with or included in the Domingo* sequence rocks. Not only are the thicknesses impossible to measure (the given numbers are only guesses), but the stratigraphic relationships between units are seldom visible; some of Cabaiguan* sequence outcrops are entirely surrounded by Domingo* sequence ultrabasics.

The section is graphically shown in Figure 136, where the thicknesses are for illustration purposes only. Iberia Formation.—This unit, for the reasons mentioned above, is in itself essentially a wastebasket, including much of the Cabaiguan* sequence rocks. It consists of a large variety of rock types ranging from the Albian to the Maastrichtian. Pyroclastic rocks form 80% of the formation; lavas and dikes form 15%; and the sediments, including conglomerates, and sandstones and limestones form only 5%. Kozary (1968) named equivalent volcanics in the Silla Gibara the Lima (flows) and Colorado (tuffs) formations. Four members are recognized, but the relationships between each other and the rest of the section are obscured by tectonism. The main lithologies are as follows: 1) The pyroclastics consist of a. Basic tuffs and agglomerates. They are thick bedded, and the color is dark gray, with a greenish matrix. The size ranges from fine to 8 in. (20 cm) in the agglomerate blocks. The fragments commonly consist of basalt or basalt-andesite, occasionally amygdaloid, and the cement is pumiceous. b. Intermediate tuffs and agglomerates. Their color is greenish gray to grayish with a violet matrix. The fragments consist of andesites and andesite porphyries with recrystallized volcanic glass and opaque sericitized fragments. Occasionally, amygdules are present and are filled with zeolites and carbonates. 2) The lavas consist of a. Augitic andesite b. Amygdaloidal andesite c. Basaltic andesite lava-breccia d. Pyroxene diabase e. Amphibolitized diabase The above lavas occur in lenticular bodies between 10 and 140 ft (3 and 40 m) thick of augitic andesite, amygdaloidal andesite, basaltic andesite lavabreccia, pyroxene diabase, and amphibolitized diabase. The dikes consist of diabase and basalts. 3) The sediments consist of a. Polymict conglomerates of gray to greenish gray color containing fragments of tuffs, tuffaceous sandstones, limestones, andesites, basalts, and fossil fragments (rudists). The fragments vary from angular to rounded, with a diameter up to 3 in. (7 cm). The cement is calcareous. b. Well-bedded, greenish, brownish gray to yellowish brown, medium- to coarse-grained tuffaceous sandstones.

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c. Fine-grained clastics interbedded with cherts. d. Lenticular intercalations of light-gray to purplish, dense, porcelaneous, tuffaceous limestones. Their fauna consists of Ticinella sp., Stomiosphaera sphaerica, Hedbergella sp., Globotruncana sp., Globigerinelloides sp., rudist fragments, and radiolaria, suggesting an Albian– Turonian age. These limestones are associated with cherts. The thickness of the above-described volcanicsedimentary part of the Iberia Formation is estimated at 3330–4000 ft (1000–1200 m). Koza´k (1996, p. 212) estimates ‘‘500 to 2000, perhaps 4000 m.’’ The formal members are La Morena, Tinajita, Lindero, and La Jiquima. In Pushcharovsky et al. (1988), the last three units are given the rank of formation. La Morena is not shown and is probably included in the Iberia Formation. La Morena Member. —This unit consists of ±100 ft (±30 m) of well-bedded alternation of white, compact limestone and friable, creamy white marl. It appears to be the only member belonging or related to the Iberia Formation. The fauna consists of Heterohelicidae, Calcisphaerula innominata, Stiomosphaera sphaerica, Praeglobotruncana sp., Globotruncana cf. fornicata, Globotruncana linneiana tricarinata, Globigerinelloides sp., and radiolaria, indicating a probable Albian – Turonian age. Tinajita Member.— This unit was named by Kozary (1968) who considered it part of a Maastrichtian forereef. It consists of massive, dense, beige, light-gray, and yellowish white, oolitic, organoclastic limestones with undefined thick bedding. Among the fossils, Globotruncana lapparenti bulloides, Globotruncana linneiana, Globotruncana calciformis, Globotruncana fornicata, Globotruncana stuarti, Globotruncana contusa, Globotruncana conica, Torreina torrei, Solenopore piai, Pseudorbitoides israelskyi, Sulcoperculina globosa, Sulcoperculina dickersoni, Sulcoperculina diazi, Sulcorbitoides pardoi, Actinorbitoides browni, Vaughanina cubensis, Vaughanina barkeri, and Orbitoides tissoti have been identified, indicating a probable Santonian–Campanian or Campanian age. Lindero Member.— The unit consists of up to dozens of meters of medium, well-bedded, light-gray, greenish, or pink, commonly silicified, dense, and porcellaneous limestones. Among the fossils Globotruncana cf. lapparenti, Globotruncana cf. linneiana, Hedbergella sp., Rugoglobigerina sp., Pseudotextularia elegans, Heterohelix sp., and radiolaria have been identified, indicating a probable Campanian–Maastrichtian age.

La Jiquima Member. —The unit is made of at least 1000 ft (300 m) of fine- to medium-bedded, well-sorted, fine- to medium-grained, brownish gray to creamy brown sandstones. Carbonized plant fragments are common. Sulcoperculina sp., Globotruncana sp., and Gyroidina sp. have been identified, suggesting a Campanian–Maastrichtian age. Although no direct evidence exists, it is believed that the Tinajita and Lindero members are interbedded with the Jiquima Member, and that all three lie unconformably over the Iberia Formation. The stratigraphic subdivision of the above section is not entirely clear. From the above descriptions, it appears that the Iberia Formation, including the La Morena Member, forms a lower unit of Albian – Turonian age, which is unconformably overlain by another unit that includes the Tinajita, Lindero, and La Jiquima members of Campanian – Maastrichtian age; the section is shown in this way in Pushcharovsky et al. (1988). Koza´k (1996) named the Loma Blanca Formation and separated it from the Iberia Formation, which consists of more acidic and mature calc-alkaline flows, associated tuffs, and some sediments. Age dating by the K-Ar method has given ages of 81 ± 3 and 86 ± 5 Ma, or Santonian. Haticos Formation. — This unit consists of ±650 to ±3300 ft (±200 to ±1000 m) of a coarse conglomerate (wildflysch) interbedded with pumiceous tuffs. The components of the conglomerate are poorly sorted and angular to rounded and consist of serpentine, gabbro, microgabbro, diabase, granodiorite, and the volcanics and volcaniclastics of the Cabaiguan* sequence. The matrix is a volcanic-derived sandstone, siltstone, and white, yellow, or gray marls and tuffs. Interbeds of brown and yellowish brown, well-sorted, thinly bedded, fine- to coarse-grained sandstones are present. The components are plagioclase, quartz, pyroxene, and olivine. Named by Kozary (1955a, b; 1968). P. Jakus describes another formation, the Yaguajay Formation (no relation to Gulf’s Yaguajay*) that, like the Vega Alta, represents a structural mixture of rocks belonging to different tectonic-stratigraphic belts or zones. It is not considered a legitimate formation and, therefore, will not be included in this publication. The Yaguajay Formation is shown in Pushcharovsky et al. (1988). Fossils are rare, but Globorotalia velascoensis, Globorotalia aequa, Milliolina sp., radiolaria, and echinoids have been found. Jakus (1983) considers this unit of late Paleocene age. This unit was deposited in deep waters, and the presence of tuffs (if not entirely

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detrital) indicates the influence of some volcanic activity. The Haticos Formation unconformably overlies the Domingo* and Cabaiguan* sequence rocks in northern Oriente and is transgressively overlain by the Vigia Formation. Except for the presence of tuffs, the Haticos shows great similarity with the lower – middle Eocene Vega* and Rosas* formations of central Cuba and the Pica Pica and Vieja members of the Manacas Formation of western Cuba. It also shows great affinity with the earlier Paleocene Taguasco* Formation of central Cuba. Vigia (Vigia Oriental) Formation. — This Eocene unit is unconformably above the Domingo* and Cabaiguan* sequence rocks. According to Jakus (1983) and Pushcharovsky et al. (1988), this unit overlies both the Embarcadero Formation in the Gibara area and the Haticos Formation in the Domingo*–Cabaiguan* sequence. It is definitely a deep-water deposit, and its lower part suggests the Vega* flysch of central Cuba; however, unlike the Vega* Formation, it represents the transition to molasse deposition over the arc, followed by a renewal of volcanic activity. Here, the Charco Redondo Formation covers it unconformably. Charco Redondo Formation. — The unit (named by Woodring and Davies, 1944) consists of 150–650 ft (50–200 m) of compact, varicolored (white, beige, yellowish brown, pinkish yellow, and yellowish red), bioclastic limestones. Intraformational limestone breccias and thickly bedded white limestones characterize its lower part. In the upper part, the brownish colors predominate, the bedding is thinner, and the bioclastic texture is dominant; some horizons consist entirely of large-foraminifera coquinas. The following foraminiferal fauna has been identified: Amphistegina lopeztrigoi, Amphistegina cubensis, Amphistegina parvula, Asterocyclina monticellensis, Asterocyclina habanensis, Dictyoconus americanus, Discocyclina marginata, Distychoplax biserialis, Eoconuloides wellsi, Fabiania cubensis, Globorotalia densa, Globorotalia aragonensis, Globorotalia apanthesma, Globorotalia mckannai, Globigerina soldadoensis, Helicostegina gyralis, Helicostegina dimorpha, Pseudopragmina habanensis, Pseudopragmina psila, Pseudopragmina convexicamerata, Nummulites bermudezi, and Nummulites floridensis. The age is considered middle Eocene. This unit is poorly represented in northern Oriente, where it unconformably overlies the Vigia Formation. This is the youngest pre – upper Eocene unit. It is also present in southeastern and southwestern Oriente.

Domingo*–Cabaiguan* Sequences Discussion.— Structural complications conceal the nature of the general succession in the basic igneous-volcanic province. It should be noted that Kozary (1968) attempted to reconstruct a trench (the Auras Trench) based on the type of sediments included in the many imbrications of the Silla Gibara. The Domingo* sequence is extremely disturbed, but most of its components can be recognized, including the gabbros, the metamorphic exotics, and the sheeted dikes complex. Serpentinization is not as intense as in other parts of Cuba; however, a peculiar situation in this area is that there is a variety of limestone blocks, up to 1 km (0.6 mi) in length and mostly of Late Cretaceous age, embedded in the ultrabasics. Even more peculiar is the fact that Cabaiguan* sequence volcanics form tectonic wedges between wedges of ultrabasics, but are not directly associated with the limestones also embedded in the ultrabasics. This situation is unique in Cuba because elsewhere, unmetamorphosed limestone exotics in ultrabasics are extremely rare. This situation is what led Kozary, in his work for his Ph.D. thesis, to postulate Upper Cretaceous, dominantly carbonate sediments filling the Auras Trench, which was then destroyed by the collapse of its ultrabasics south wall into the trench in the Eocene, thus incorporating the carbonate sediments within the ultrabasics. The Cabaiguan* sequence wedges were considered by him as part of an arc, over the ultrabasics and immediately south of and parallel to the Auras Trench. This interpretation has much merit except that the limestones embedded into the ultrabasics are different from those of the Las Villas*, Placetas*, and Cifuentes* belts; no Upper Jurassic or typical Lower Cretaceous nannoplankton limestones and cherts have been recognized. Jakus (1983) does not provide any further information because he lumps most of these lithologies in the Yaguajay Formation ‘‘melange’’ and assigns the larger outcrops to units such as the Tinajita Member of the Iberia Formation. In 1968, Kozary postulated that tension was responsible for the Auras Trench, and that it was located at the contact between the granitic crust under the carbonate platform to the north and the oceanic basement under the basic igneous-volcanic province to the south. If such a trench existed, and this is quite possible, it would not have been directly related to the platform to deep-water province discussed under central and western Cuba, but could have been located south of it, separating it from the basic igneousvolcanic province. Considering that the Auras Trench

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is postulated to have originated in the Lower Cretaceous, it could be partially superimposed on the platform to deep-water province. It is believed that Kozary, in his work for this Ph.D. thesis, was the first geologist to propose a period of rifting to explain the Cuban ultrabasics prior to the advent of an orogenic arc. It should be remembered that the Jurassic – Cretaceous sedimentary basin does not outcrop in Oriente, has very few outcrops in Camaguey, outcrops continuously in Las Villas, and is extensively exposed in Pinar del Rio. The structural complications and tectonic shortening appear to be inversely related to the area of surface exposures of these sedimentary facies. This suggests that the platform to deep-water province was either wider in the west and narrowed eastward or was tectonically more compressed and overridden toward Oriente. The lower part of the Cabaiguan* sequence (the Iberia Formation) is of Albian –Turonian age. Most of the deposits consist of basic to intermediate tuffs, and the subordinate flows and dikes consist of basalts and andesites. The position of the limestones within the section is unknown, but they are equivalent in age to the Cristobal*, Gomez*, and Camujiro of central Cuba as well as to the Encrucijada Formation of the Bahia Honda area of Pinar del Rio. Unfortunately, it is impossible to reconstruct the history of volcanism. No paleontological record of the Coniacian and Santonian exists; Santonian rocks have been dated, however, by radiometric methods. The Campanian – Maastrichtian is represented by the clastics of the La Jiquima Member, believed to be associated with the carbonates of the Tinajita and Lindero members and to lie unconformably over the Iberia Formation. There is the problem of the carbonates, such as the Tinajita Member, tectonically mixed with the ultrabasics; perhaps these were deposited directly over an ultramafic basement after erosion (or perhaps nondeposition) of older postTuronian – Cretaceous volcanics. The only indications of Manicaragua-type intrusives are outcrops under the city of Holguin covering some 5 km2 (2 mi2). They consist of quartz diorite porphyry dated at 77 ± 10 m.y. by the K-Ar method. The Paleocene is represented by a megabreccia, derived from the erosion of the Domingo* and Cabaiguan* sequence rocks, interbedded with sandstones and tuffs, indicating some volcanic activity in the region. This wildflysch corresponds to the Taguasco* Formation of central Cuba; although granodiorite is mentioned as a component, there is no mention of an arkosic character.

The upper Paleocene to middle Eocene is represented first by what appears to be flysch deposition in deep waters, but is followed by fine clastics and volcanics, suggesting a molasse cycle and, of great importance, volcanic activity that is coeval with, or even might follow, the maximum tectonic activity. The Vigia Formation is present north and south of the fault separating the carbonates from the Gibara area from the Domingo*–Cabaiguan* sequences. It grades from coarse to fine upward, indicating that it was deposited after the maximum displacement on this fault.

Southeastern Oriente This region extends from the south of Nipe Bay to the southeastern tip of Cuba, south of Baracoa. It is in large part formed by the Sierra de Cristal. The structural style is quite different from that of northern and central Cuba and from northern Oriente; it is reminiscent of the Sierra de Guaniguanico in western Cuba. The structures consist of large, relatively undisturbed, horizontal thrust sheets of ultrabasics and volcanics cut by numerous high-angle faults. Although evidence for large horizontal displacements exists, the high degree of compression and shortening present along the axial Cuban disturbed belt is lacking. Only the basic igneous-volcanic and metamorphic provinces are represented. The Domingo* sequence rocks cover more than 50% of the region, the Cabaiguan* sequence covers approximately 30%, and variously metamorphosed sediments and volcanics represent less than 20% of the area in the massif of the Sierra del Purial and the small Asuncion area. The basic igneous-volcanic province forms a nearly continuous band of outcrops of 180  25 km (111  15 mi), extending from the south of the Bay of Nipe to the south of Baracoa. Two other, small, isolated outcrops are present, one south of San German and the other near San Antonio near the southern coast. In Pushcharovsky et al. (1988), the middle Eocene Gran Tierra, Miranda, Castillo de los Indios, Puerto Boniato, and Charco Redondo formations are included in the Bayamo–San Luis Basin, although they pertain to the pre–upper Eocene late orogenic cycle. This basin is located between southeastern and southwestern Oriente. In this study, these formations will be discussed under southeastern and southwestern Oriente.

Domingo* Sequence Rocks of this belt cover a large percentage of the area of this province. They are distributed in two large tabular bodies, which have been called the Mayari and

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FIGURE 137. Stratigraphic section: Domingo*-Cabaiguan* sequences, eastern Cuba, southeastern Oriente.

Baracoa massifs (see Figure 134). The section is diagrammatically shown in Figure 137. It consists of the following. Corea Formation.—This consists of a large block, some 10 km (6 mi) long of albite-amphibole-epidote schist. It has much muscovite and some chlorite. It is

believed to have originated from volcanic rocks of basic to intermediate composition under conditions of high pressure and intermediate temperature. This block is an exotic in the ultrabasics and is similar to some of those occurring in the Santa Clara area in central Cuba. I am not sure that a formation name is

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justified. Age determinations by Rb/Sr have given 79 ± 32 m.y. for the whole rock and 72 ± 28 m.y. for the muscovite. One pegmatite dike cutting the schist was dated at 119 ±12 m.y. by K-Ar. This suggests a date of Upper Cretaceous for the metamorphism but Lower Cretaceous for the intrusion. Ultrabasic Complex. —It consists of layered peridotites, harzburgites, lherzholites, dunites, etc., in various degrees of serpentinization. In composition, it is similar to the other Cuban ultrabasic complexes. Structurally, this complex is part of a large, nearly horizontal, ±2600-ft (800-m)-thick slab resting in fault contact over rocks of the unmetamorphosed Cabaiguan* sequence, as well as those of the Purial metamorphic complex. The roots of this thrust sheet can be seen in discontinuous outcrops south of the Sierra del Purial massif. The base is characterized by an ultrabasic breccia in a serpentine matrix. Gabbros. — Toward the east, southwest of Baracoa, are outcrops of gabbros, most of them in fault contact with the ultrabasics. Sheeted dikes. — These have been identified in several localities. Note that no report exists of rocks older than Maastrichtian resting in sedimentary contact over the ultrabasic complex. These may never have been deposited or were eroded prior to the Maastrichtian. This could be an undisturbed equivalent of the sedimentary exotics in the disturbed ultrabasics of northern Oriente.

Cabaiguan* Sequence Most of the outcrops of the Cabaiguan* sequence are found structurally under the ultrabasics of the Domingo* sequence (see Figure 134). The section is also shown in Figure 137. Bucuey (Santo Domingo, Teneme) Formation.— The unit consists of 6900 ft (2100 m) of tuffs, lavas, and subordinate amounts of agglomerates. Small bodies of dioritic porphyries, andesites, and diabases are also present, as well as thin horizons of limestone and rare small lenses of conglomerate. This unit was named by Coutı´n and Brito (1975). Part of this formation was named Santo Domingo by Iturralde-Vinent (1975a, b). It is shown as Santo Domingo (Bucuey) and Teneme (Bucuey) in Pushcharovsky et al. (1988). The major lithologic types are as follows: 1) Tuffs. They make up more than 50% of the formation and dominate in the upper part of the unit. They are greenish gray, bluish gray, and light green when fresh, weathering to brownish and

chocolate grayish brown. They are well bedded with thin to medium beds and are fine to medium grained. Crystalline, vitric-clastic types dominate. The lithic crystalloclastic types are secondary. 2) Lavas. They consist of small bodies of massive, greenish gray, medium- to coarse-grained diorite porphyries, brownish fine- to medium-grained diabase, and very rare, black, coarse-grained andesites. 3) Agglomerates. They are commonly associated with the lavas and have an andesite to dacite composition. According to Pushcharovsky et al. (1988), the Bucuey Formation is divided into the Teneme Formation, limited to the north and western part of the Cabaiguan* sequence outcrops and consisting of basalts and andesite-basalts, tuffs, and breccias; and the Santo Domingo Formation, outcropping to the southwest of the Cabaiguan* sequence and consisting mostly of tuffs, andesites, agglomerates, conglomerates, and limestones. The position of the limestones is not well defined, and for this reason, they have been assigned to a separate member within the Bucuey (Santo Domingo, Teneme) Formation. Barraderas Member.—It consists of 130–160-ft (40– 50-m)-thick lenses of well-bedded, micritic, sometimes brecciated, white to creamy white or gray limestones. In Pushcharovsky et al. (1988), it is shown as part of the Teneme (Bucuey) Formation. The limestones are commonly strongly folded and slaty and occur in several different localities. Based on the presence of Preaglobotruncana helvetica and Ticinella (Hedbergella?) sp., they have been given an Aptian – Turonian age. It must be stressed that the age of the Bucuey Formation is entirely based on the age assignment of these limestones. This formation is therefore equivalent to the Iberia Formation in northern Oriente, and the Barraderas Member is a possible correlative to the La Morena Member. It must be emphasized that, in contrast with the Iberia Formation and with the exception of the proximity of faults, the dips are generally low, 15–308. The base of the Bucuey Formation has never been observed, but Jakus (1983) considers this section autochthonous and probably equivalent to the greenschists of the La Farola Formation. Yaguaneque Formation. — This unit consists of more than 35 ft (10 m) of white, cream, or gray and sometimes brown, massive limestone. It is commonly criss-crossed by small, white calcite veins. It is known only as two small separated patches in the north coast. The fauna consists of Pseudorbitoides cf. israelskyi, Vaughanina sp., Sulcoperculina cf. globosa, Orbitoides

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sp., Omphalocyclus sp., Globotruncana cf. stuarti, Globotruncana cf. fornicata, Globotruncana linneiana, Globotruncana contusa, Sulcorbitoides sp., Globigerinelloides sp., rudistids, and rare radiolaria. The age is considered Campanian–Maastrichtian. This unit is believed to unconformably overlie the La Farola Formation. Picota Formation. —It consists of up to 3300 ft (1000 m) of interbedded conglomerates, sandstones, and siltstones. The dominantly sandy and silty section has been named the Mı´cara Member. The Picota Formation is mostly a polymict, poorly sorted, reddish, mottled conglomerate and breccia with boulders up to 10 in. (25 cm) in diameter. The components consist of lavas, tuffs, diorites, gabbros, serpentine, and, in lesser quantity, limestones. The composition of the detritus varies from place to place from dominantly ultrabasic to dominantly volcanic. The textural appearance also changes from detrital sediment to an angular tectonic breccia without bedding or orientation. Colbiella (1974) named it the Sabanilla Formation and divided it into the La Picota and Mı´cara members. The conglomerates are very poor in fossils, but a limestone lens between the sandstones and conglomerate has given Sulcoperculina globosa, Vaughanina cubensis, Vaughanina cubensis globosa, and bryozoans, indicating a Maastrichtian age. The conglomerates interfinger with the finer clastics of the Mı´cara Member. Mı´cara Member. — The unit consists of darkgray, greenish gray, and dark-green, well- and fine- to medium-bedded sandstones and siltstones, with interbeds of conglomerates and dolomitized limestones. Graded bedding and crossbedding are common. The sandstones are fine to coarse grained, and the components consist of subrounded rock fragments, plagioclase, quartz, chalcedony, calcite, and ultrabasics. The matrix is calcareous. The siltstones are of gray color, and the components consist of rock fragments, plagioclase, quartz, and calcite in a fine matrix. The contact between the sandstones and siltstones is commonly sharp, erosional, and wavy. The clasts of the conglomerates are rounded to subangular, up to 8 in. (20 cm) in diameter, and consist of Bucuey Formation volcanics, gabbros, diorite porphyry, limestone, and occasionally, serpentine. The matrix is sandy. A rich nannoplankton assemblage (coccoliths, zygodiscs, etc.) has been identified, as well as Pseudorbitoides cf. israelskyi, Sulcoperculina globosa, Asterorbis sp., Hedbergella planispira, Preaglobotruncana sp. (reworked), Gyroidina sp., and Inoceramus sp., suggesting a Campanian– Maastrichtian age. The Picota Formation and Mı´cara Member appear to have been deposited as flysch in open water as the

result of the erosion of an advancing thrust front. Jakus (1983) considers it in part fluviatile-deltaic as indicated by the localized presence of lignites. Both units are found under the major ultrabasic thrust sheet that covers a large part of the southeastern Oriente region. They unconformably overlie the Bucuey Formation and, in places, the ultrabasics; they are also found folded into the ultrabasics. They are conformably overlain by the Gran Tierra Formation and unconformably overlain by the Castillo de los Indios Formation. Gran Tierra Formation. — The unit (named by Iturralde-Vinent, 1975a, b) consists of small irregular patches, 500 – 650 ft (150 – 200 m) thick of conglomerates and breccias with calcareous cement and marls grading upward into white limestone breccias. The clasts are fresh and rounded consisting mostly of the volcanics of the Bucuey Formation and minor amounts of gabbros, serpentine, sandstones, etc. The marls are creamy yellow. The fossils Globorotalia pseudobulloides, Globorotalia trinidadensis, Globorotalia imitata, and Globigerina triloculinoides have been identified, suggesting a lower Paleocene age. It conformably overlies the Picota Formation (Mı´cara Member) and is found unconformably over the ultrabasics, the Cabaiguan* sequence Bucuey Formation, and the greenschists of the metamorphic province La Farola Formation. It is commonly overlain by the acid tuffs of the Miranda Formation. This unit is considered equivalent to the Haticos and Embarcadero formations of northern Oriente. Miranda Formation. — The Miranda Formation consists of generally 1000 – 1150 ft (300 – 350 m), occasionally reaching 3000 ft (900 m), of thin- to medium-bedded, porous, vitroclastic, lithovitroclastic, and crystallovitroclastic tuffs with smaller amounts of conglomerates, breccias, marls, and limestones. Small bodies of andesites, andesitic basalts, and dacitic andesites are also present. The colors range from greenish, greenish yellow, yellowish white, and gray to white. Depending on the area, the alteration is dominantly zeolitic or bentonitic, although the tuffs are also silicified and chloritized. In places, a poorly sorted conglomeratic breccia (lenses?) is present, up to 800 ft (250 m) in thickness, with clasts up to 5 in. (12 cm), of andesitic volcanics and aphanitic, white limestone containing upper Paleocene–lower Eocene faunas. The matrix is dominantly a slightly argillaceous vitroclastic tuff. In addition to the presence of nannoplankton in the Miranda Formation, the following fossils have been identified: Globorotalia velascoensis, Globorotalia aequa,

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Globorotalia pseudomenardii, Globorotalia occlusa, Globorotalia spinulosa, Globorotalia rex, Globorotalia formosa, Globorotalia crassata, Globorotalia pseudobulloides, Globorotalia compressa, Globorotalia elongata, Globorotalia cf. wilcoxensis, Globorotalia cf. aragonensis, Globigerina cf. mckannai-soldadoensis, Globigerina linaperta, Globigerina velascoensis, Globigerina triloculinoides, Pseudophragmina sp., Discocyclina cf. cristensis, Discocyclina marginata, Discocyclina cf. cubensis, Amphistegina cf. lopeztrigoi, and Asterocyclina cf. habanensis. The age is considered upper Paleocene to middle Eocene. The Miranda Formation rests unconformably on the Picota and Gran Tierra formations, as well as on the Cretaceous volcanics, the ultrabasics, and the metamorphics of the Sierra del Purial. It is unconformably overlain and overlapped by the upper Eocene. It is equivalent to the Cobre and Vigia formations of southwestern Oriente. Its upper part might be correlative to the lower part of the Castillo de los Indios Formation. Castillo de los Indios Formation. — The unit consists of a maximum of 800 ft (250 m), but 230 ft (70 m) on average, of thin- to medium-bedded lithoclastic and lithovitroclastic tuffs. The fragments in the vitroclastic tuffs consist of somewhat altered volcanic glass of fine to medium size, but occasionally up to 3 in. (8 cm) in diameter. Also well distributed in this formation are limestones, marls, and light-gray to yellowish white thin-bedded siltstones. In some areas, the limestones dominate. The fauna consists of nannoplankton (cocolithophoridae and discoasteridae) and foraminifera, including Truncorotaloides rohri, Truncorotaloides topilensis, Hantkenina alabamensis, Globorotalia cf. convexa, Globorotalia densa, Globorotalia centralis, Amphistegina cf. cubensis, Amphistegina lopeztrigoi, Distychoplax biserialis, Fabiania cubensis, Globanomalina cf. wilcoxensis, and Globigerina senni, indicating a lower–middle Eocene age perhaps extending into the upper Eocene. This formation lies conformably over the Gran Tierra Formation and unconformably over the ultrabasics. The Puerto Boniato Formation overlies it with a slight unconformity. It is equivalent to the upper part of the Vigia Formation in northern Oriente. Puerto Boniato Formation. —This unit consists of up to 160 ft (50 m) of thin-bedded, cream to whitish cream, dense, sometime bioclastic limestones interbedded with brownish black chert and lightgray marls. The foraminiferal fauna consists of Discocyclina marginata, Discocyclina cubensis, Amphistegina lopeztrigoi, Asterocyclina habanensis, Asterocyclina monticel-

lensis, Eoconuloides wellsi, Globorotalia cf. wilcoxensis, Globorotalia cf. elongata, Globorotalia cf. convexa, Globorotalia cf. pseudomenardii, Globigerina cf. mckannai, Globigerina cf. soldadoensis, Trancorotaloides topilensis, Lepidocyclina ariana, Lepidocyclina macdonaldi, Pseudophragmina habanensis, and Pseudopragmina teres. The age is considered middle Eocene. It lies conformably on the Miranda and unconformably on the Castillo de los Indios Formation. Charco Redondo Formation. — It is well represented in southeastern Oriente, where it lies unconformably over the ultrabasics and the Bucuey, Picota, Miranda, and Vigia formations. It is the youngest pre– upper Eocene unit. Domingo*–Cabaiguan* Sequences Discussion.— This province in southeastern Cuba is characterized by relatively low dips and a major, nearly horizontal overthrust of the Domingo* over the Cretaceous part of the Cabaiguan* sequence, as well as over the metamorphics of the Purial massif. The general structural style is reminiscent of that found in the Sierra de Guaniguanico in Pinar del Rio, except that it involves the basic igneous-volcanic province instead of the clastic and platform to deep-water province. The Aptian–Turonian volcanics of the Bucuey Formation are overlain by the flysch deposits of the Picota Formation, which is synchronous with the thrusting of the Domingo* sequence sheet in the Maastrichtian; the Picota contains abundant ultrabasic fragments, occurs under the ultrabasics, and is also infolded into, and lies above them. The base of the Cabaiguan* sequence volcanics is unknown; in contrast to central Cuba, where many thousands of feet of Cretaceous volcanics are seen resting on the ultrabasics, here, no volcanics of Cretaceous age exist over them. The Gran Tierra Formation of lower Paleocene age is the oldest unit that appears to transgress both the ultrabasics and the Picota and the Bucuey formations. Here, as in northern Oriente, there was a renewal of volcanic activity during the late Paleocene and the middle Eocene that correlates with that of the Cobre Formation in southwestern Oriente. As in central Cuba, the flysch grades into a molasse as the tectonic activity decreases in intensity. Southeastern Oriente can be used as a model to interpret the structural and stratigraphic relationships in northern Oriente. If the Domingo* and Cabaiguan* sequence rocks here were to be strongly imbricated and compressed, they would show major imbrications of the Cretaceous Cabaiguan* sequence and the Domingo* sequence, but only Paleocene to middle Eocene sediments would be found as exotics in the

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ultrabasics. The situation is similar to northern Oriente, with the exception that the exotics in the ultrabasics consist only of Maastrichtian and younger sediments. This indicates that, in northern Oriente, the thrusting and erosion of the Domingo*–Cabaiguan* thrust sheet occurred at an earlier period in Campanian– Maastrichtian. A very high 180 mg Bouguer gravity value over the ultrabasics and metamorphics is probably not caused by the near-surface rocks, but suggests a shallow oceanic basement under the thrust sheets. For instance, the Domingo* sequence in northern Oriente, which is along the main Cuban deformation zone, shows values of 10 mg or less, although the ultrabasic outcrops are nearly as extensive. It is possible that what appears to be a thrust sheet represents a cold extrusion and gravity flow of serpentinized ultrabasics from several feeders. It should be noted that no direct evidence for the direction of thrusting of the ultrabasics has been reported; however, this thrust sheet is believed by Cobiella et al. (1984) to form a major anticline with its roots southward, toward the Cayman Trench. The Cabaiguan* sequence is considered to be autochthonous. The original width of the exposed Domingo* and Cabaiguan* sequences must have been a minimum of 85 km (52 mi) before thrusting. However, if the serpentine originated from local feeders and spread as submarine flows, this width might not be more than 45 km (28 mi).

Southwestern Oriente This region extends for 250 km (155 mi) west of Guantanamo Bay along the southern coast of Cuba. It reaches north as far as Tiguani. As shown in Figure 134, it is a large uplift, the Sierra Madre, north of the Cayman Trench, and it is a continuation of the Cayman Ridge. Here, the basic igneous province is represented only by rocks of the Cabaiguan* sequence. With the exception of small Cretaceous volcanic outcrops, the Paleogene dominates the region.

Cabaiguan* Sequence Two small Cretaceous outcrops, the Tejas and Bruja Oriental formations, probably form the basement under a thick Paleogene volcanic section, which is characteristic of this region. Paleogene volcanics have been previously described in other regions of eastern Cuba and also as tuffs included in the sediments of northern and central Cuba. Here, however, the Paleogene volcanic section is well developed and appears continuous, as shown in Figure 138. However, there is

a question whether Cretaceous sediments have been legitimately included in the Cobre Group. Bruja Oriental Formation. —Pushcharovsky et al. (1988) show near the southern coast of Oriente, some outcrops of this Campanian – Maastrichtian unit in fault contact with the Cobre Group. They are described as sandstone, tuffaceous siltstone, sandy limestone, and conglomerate. Despite the name, this unit does not seem to have any relationship with the Bruja Formation of central Cuba, and the origin of this name and the basis for the dating is unknown. Cobre group. — The Cobre Group consists of 16,500–20,000 ft (5000–6000 m) of a complex, dominantly andesitic, effusive, and volcanoclastic section including lavas, agglomerates, lithocrystalloclastic, and vitroclastic tuffs, calcareous tuffs, and lenses and beds of bioclastic and tuffaceous limestones. The different lithologic types grade into each other laterally and vertically, which makes it extremely difficult to subdivide this unit. Numerous dioritic intrusive bodies cut the Cobre Group, causing much contact metamorphism of the intruded rocks. The various components are as follows: 1) Andesites. This is the most common effusive type present as lava flows, sills, dikes, and related tuffs and agglomerates. The color is commonly gray, with hues that can be green, violet, brown, and sometimes almost black. The texture is commonly porphyritic with an ophitic matrix. The composition is very uniform; the phenocrysts commonly consist of andesine and sometimes augite. The matrix is mostly made up of plagioclase accompanied by grains of pyroxenes, metallic minerals, and glass. 2) Dacites and andesitodacites. This type is fairly common. The color is commonly gray, with hues that can be violet, brown, and sometimes green. They are finely porphyritic, with a glassy or holocrystalline (recrystallized) matrix. The phenocrysts are commonly acid feldspars (from oligoclase to albite), quartz, and metallic minerals. The andesitodacites contain less quartz in the phenocrysts. 3) Rhyolites and rhyodacites. These are the least abundant effusives. They also have a porphyritic texture; the phenocrysts consist of quartz, acid plagioclase, and mafic minerals in minor quantities. The matrix contains plagioclase, biotite, and grains of metallic minerals. 4) Pyroclastics. The kind of pyroclastics are present in the same proportions as the above corresponding effusive rocks.

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FIGURE 138. Stratigraphic section: Cabaiguan sequence, eastern Cuba, southwestern Oriente.

5) Tephras and agglomerates. They show a variation from acid to basic. 6) Tuffs. They are commonly well bedded, fine to very fine grained, and present a large range of light to dark colors. They commonly represent the up-

per part of the various volcanic cycles and are commonly associated with tuffaceous limestones. 7) Graywackes. They are abundant only in the western part of the Sierra Maestra. They are commonly well bedded and well sorted with subangular grains.

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These sediments and volcanics were deposited in an open-marine environment with variable depth. Among the characteristic fossils, the following species have been recognized: Globigerina spiralis, Globigerina aquiensis, Globigerina mckannai, Globigerina primitiva, Globorotalia acuta, Globorotalia aequa, Globorotalia convexa, Globorotalia crassata, Globorotalia pseudoscitula, Globorotalia pseudopilensis, Globorotalia brodermani, Globorotalia (Morozovella) aragonensis, Globorotalia (Acarinina) densa, Hantkenina bumblei, Catapsydrax echinatus, Discocyclina barkeri, Discocyclina mestieri, Discocyclina marginata, Discocyclina cubensis, Pseudophragmina (Proporocyclina) cedarkeyensis, Pseudophragmina (Proporocyclina) habanensis, Pseudophragmina (Proporocyclina) psila, Amphistegina lopeztrigoi, Amphistegina cubensis, Asterocyclina habanensis, Nummulites bermudezi, Cymbalopora cushmani, Eoconuloides wellsi, Boreloides cubensis, Helicostegina gyralis, and Fabiana cubensis. This assemblage indicates the lower– middle Eocene. However, some limestones of the Palma Mocha Formation contain Sulcoperculina dickersoni and Pithonella sp., suggesting an Upper Cretaceous age. Within the Cobre Group, several formations have been defined: Hongolosongo, Cuabitas, Pı´lon, and Palma Mocha. They do not constitute a complete subdivision of the group, but instead, they represent some characteristic lithologic associations that can be locally mapped. They do not constitute a stratigraphic succession. Hongolosongo Formation. — This unit (named by Yikdov et al., 1971, and shown as a formation in Pushcharovsky et al., 1988) consists of a variable thickness, up to a maximum of 10,000 ft (3000 m), of yellowish gray, poorly bedded acid tuffs (dacites, riodacites, rhyolites) interbedded with frequent agglomerates, lapillis, and ignimbrites. Lavas of the same composition and dikes of diorite and basalt porphyries are also present. The fauna is poor, but Distychoplax sp., Boreloides cubensis, and Eoconuloides wellsi have been identified. This member is under the limestones of the Cuabitas Formation that contain a rich lower–middle Eocene fauna. Cuabitas Formation.— This unit consists of up to 200 ft (60 m) of limestone lenses, occasionally reefoidal, that appear to have grown on volcanic islands. The following species have been identified: Globigerina spiralis (or aquiensis), Globigerina mckannai, Globorotalia cf. pseudopilensis, Globorotalia (Morozovella) aragonensis, Globorotalia (Acarinina) cf. densa, Discocyclina barkeri, Discocyclina marginata, Discocyclina cubensis, Pseudophragmina (Proporocyclina) cedarkeyensis, Amphistegina

lopeztrigoi, Asterocyclina habanensis, Eoconuloides wellsi, Boreloides cubensis, Helicostegina cf. gyralis, Distychoplax sp., Lithothamnium sp., and Lithophyllum sp., suggesting a lower–middle Eocene age. Pilo´n Formation. — The Pilo´n Formation (shown as a formation in Pushcharovsky et al., 1988) consists of more than 6500 ft (2000 m) of banded calcareous tuffs in the lower part, followed by graywacke and medium-grained detritus composed of volcanic fragments and, finally, massive limestones with volcanic fragments in the upper part. The following fauna has been recognized: Globigerina mckannai, Globigerina primitiva, Globorotalia cf. acuta, Globorotalia cf. aequa, Globorotalia crassata, Globorotalia pseudopilensis, Globorotalia (Morozovella) aragonensis, Globorotalia (Acarrinina) densa, Catapsydrax echinatus, Discocyclina barkeri, Discocyclina cf. mestieri, Discocyclina marginata, Pseudophragmina (Proporocyclina) cedarkeyensis, Pseudophragmina (Proporocyclina) habanensis, Pseudophragmina (Proporocyclina) cf. psila, Amphistegina cf. lopeztrigoi, Asterocyclina habanensis, Nummulites bermudezi, Eoconuloides wellsi, and Fabiania cubensis. This assemblage is lower–middle Eocene; however, this formation is believed by Jakus (1983) to extend into the Upper Cretaceous. It is reported to contain abundant Cenomanian –Turonian reworked fragments. Palma Mocha Formation.— This unit consists of ±650 ft (200 m) of thin to medium, well-bedded, black to dark-gray limestones, with occasional interbeds of lithocrystalline tuffs, containing Sulcoperculina dickersoni, Pithonella sp., and radiolaria. It was named Palma Mocha Group by Furrazola-Bermudez et al. (1976). In the 1988 geologic map (Pushcharovsky et al., 1988), near the type locality of the Palma Mocha Member, a Cretaceous undifferentiated Turquino Formation was described as consisting of clastics and volcanics but shown with limestones in the columnar section. The age is considered Upper Cretaceous (Cenomanian – Turonian). Because this formation shows a certain similarity to the Gomez* Formation of central Cuba, it probably does not belong to the Cobre Group. The Cobre Group lies unconformably under the Charco Redondo and Barrancas formations. Although it is commonly concordant and transitional with the Puerto Boniato Formation, they can be occasionally separated by an unconformity. The Cobre Group is a mixture of a large number of lithologic units with an age possibly ranging from the Cenomanian to the middle Eocene. From the published descriptions, volcanic activity seems to have been continuous through the Campanian – middle

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Eocene. Much more work is needed to clarify this point. Caney Formation.—The Caney Formation consists of ±3300 ft (±1000 m) of well- and generally thinbedded tuffaceous rocks with various light colors. The acid varieties dominate, and thin zeolitized horizons are common. Many manganese deposits are associated with this formation. It is shown as a formation in the 1988 geologic map (Pushcharovsky et al., 1988). The fauna contains Globigerina mckannai, Globorotalia aequa, Globorotalia cf. pseudoscitula, Globorotalia cf. brodermani, Globorotalia cf. convexa, Globorotalia (Morozovella) aragonensis, Globorotalia (Acarinina) densa, Discocyclina barkeri, Pseudophragmina (Proporocyclina) cedarkeyensis, Pseudophragmina (Proporocyclina) habanensis, Pseudophragmina (Proporocyclina) psila, Amphistegina cubensis, Eoconuloides wellsi, and Helicostegina cf. gyralis. The age is considered middle Eocene with some reworked faunas from the Paleocene and lower Eocene. Puerto Boniato Formation.—This unit is also well developed in this region, where in most instances, it transitionally overlies the Cobre Formation. Locally, it unconformably overlies the Caney Formation. Charco Redondo Formation. —It was described under northern Oriente and is well developed in this region where its type locality is located. Farallon Grande Formation. —The unit (named by Taber, 1934) consists of 165 –4100 ft (50 –1250 m) of a polymict conglomeratic breccia with angular to subangular clasts from 1 to 4 in. (2 to 10 cm) in diameter. The sorting is poor at the base and improves upward where rhythmic bedding can be observed. Interbeds of coarse-grained sandstones and well-sorted conglomerates are present. Most of the clasts are derived from the Cobre Formation along with limestone clasts from the Charco Redondo Formation. The matrix consists of sand and reworked tuff or can be totally absent. The cement is calcareous. Discocyclina cubensis and Fabiania cubensis have been identified in a limestone lens. The clasts contain typical middle Eocene faunas, and the overlying San Luis has a late middle –upper Eocene assemblage, indicating a middle Eocene age for the Farallon Grande Formation. The Farallon Grande unconformably overlies the Pilo´n Member and the Charco Redondo Formation. It grades upward into the upper Eocene San Luis Formation and is unconformably covered by the Neogene Limones and Manzanillo formations. This unit represents the end of the flysch and beginning of the molasse deposition.

Barrancas Formation.—The Barrancas Formation consists of 200–330 ft (60–100 m) of crystallovitroclastic and vitroclastic, rhyolithorhyodacitic tuffs with coarse, gray glass fragments. White marls, cream, wellsorted, tuffaceous, and calcareous sandstones, white bioclastic limestones, and calcilutites are also present. It unconformably overlies the Caney Member of the Cobre Formation. This unit contains abundant diatoms and silicoflagellates in addition to foraminifera. The following foraminifera have been identified: Catapsydrax dissimilis, Discocyclina cubensis, Fissurina margarita, Globigerapsis kugleri, Globigerina mckannai, Globigerina trilocularis, Globorotalia aequa, Globorotalia centralis, Globorotalia cerroazulensis, Globorotalia (Acarinina) densa, Globorotaloides suteri, and Truncorotaloides topilensis, suggesting middle Eocene to the lower part of the upper Eocene. This unit correlates with the Castillo de los Indios and Miranda formations of southeastern Oriente and the upper part of the Vigı´a Formation of northern Oriente. Cabaiguan* sequence intrusives.—Along the axis of the Sierra Maestra, parallel to the Cayman Trench, are several intrusive bodies in the Cobre Formation. The following types have been recognized: aplites and micropegmatites, granodiorites and granodioritic porphyry, plagiogranite and granite porphyry, quartz-diorite and quartz-diorite porphyry, diorite and diorite porphyry, and miscellaneous dikes (spessartite, andesite, andesite-basalt, basalt, andesitedacite, dacite, and rhyodacite). Three samples of granitoids have been dated by K-Ar method on whole rock giving 46 ± 6, 49 ± 6, and 58 ± 8 m.y. or upper Paleocene to middle Eocene. Drilling. —Stanolind drilled several wells, two of them offshore, in the Guanacayabos-Nipe Basin in the late 1950s. More recently, EPEP drilled Granma-1 near Bayamo. Stanolind Rabihorcado-1. Drilled through younger Tertiary to ±3280 ft (±1000 m), where it penetrated the Cobre Formation to the total depth of 4266 ft (1205 m). Stanolind Lavanderas-1. Drilled through younger Tertiary to ±3280 ft (±1300 m), where it penetrated the Cobre Formation to the total depth of 5535 ft (1688 m). EPEP Granma-1. Drilled through younger Tertiary to ±8364 ft (±2550 m), where it penetrated the Cobre Formation to the total depth of 9898 ft (3017 m). Cabaiguan* sequence discussion. — Only the Cabaiguan* sequence is present in this province. Un-

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fortunately, because of complex structures and stratigraphy, this volcanic section is poorly understood. The pre-Paleogene section occurs either as small, scattered outcrops (Tejas, Bruja Oriental formations) or is included as possible Cenomanian – Turonian (Palma Mocha limestone member) in the Cobre Formation. This member is probably equivalent to similar limestones (Gomez*, Cristobal* Camujiro, Quin ˜ones, etc.) of the same age elsewhere in Cuba. These scattered outcrops definitely indicate the presence of an Upper Cretaceous arc. No report exists of the commonly richly fossiliferous Campanian –Maastrichtian, which is always present in southeastern and northern Oriente, as well as elsewhere in Cuba. It is not known if its absence is caused by erosion, nondeposition, or just unfavorable conditions for fossil accumulation and preservation. There are reports of numerous clasts containing Campanian – Maastrichtian faunas in conglomerates of the Cobre Formation, specifically the Pilo´n Member. In view of the fact that, in other areas, the Campanian–Maastrichtian consists of shallow-water detritus deposited in shallow to deep waters, it is very likely that during that time, this region was uplifted and, therefore, the site of nondeposition and/ or erosion. During the Paleogene, volcanic products were continuously present and dominated until the middle Eocene, when the volcanism ceased during the time of the Charco Redondo and Puerto Boniato Formation deposition. The volcanism was mainly acid, from andesitic to rhyolitic, along with the accompanying ejecta. Numerous intrusives of this age are present. Note that in the postorogenic Guacanayabo-Nipe Basin, the middle Eocene can grade into the overlying upper Eocene sediments. Although northward-directed thrusts of Cobre Formation have been observed, most of the dips in this belt are moderate (30 –508), and most faults are high angle. The present width of 45 km (27 mi) of the belt is not believed to have been much more than 70 km (43 mi) predeformation.

Metamorphosed Basic Igneous-Volcanics (Purial Massif) This province occurs in the southeastern part of the southeastern Oriente region and is named the Purial massif. It has not been as well surveyed as the Escambray massif. However, like the other metamorphic provinces in Cuba, Milla´n and Somin (1981, 1985a, b) and Millan-Trujillo (1996) studied it. In gen-

eral, the metamorphism is low grade and involves volcanic rocks. The Purial massif is in part reminiscent of the Manicaragua zone of central Cuba, including amphibolites and metamorphosed volcanics (greenschists), and represents most of the metamorphic outcrops. Their distribution is shown in Figure 134, and the units will be described generally from east to west and shown in Figure 139 (no thicknesses have been measured, and the ones given on the figure are for graphic purpose only). Gu ¨ ira de Jauco Formation. —The Gu ¨ ira de Jauco Formation consists of a schistose, sometimes banded, amphibolite of hornblende-andesine composition commonly containing garnet and quartz. Isolated intercalations of quartz-garnet cherts and garnet-hornblendeandesine-quartz, fine-grained plagiogneiss are also present. Some of the amphibolites have been definitively derived from gabbros, which show pseudobands caused by the orientation of the components that preserve relicts of the primary clinopyroxenes and basic plagioclases. In places, clinozoisite-epidote is abundant. The chemical composition corresponds to that of tholeiites. This formation contains pegmatite veins and small intrusive bodies of diorite and quartz-diorite. In the amphibolites are many lenses of serpentinite, and large blocks, up to 650 ft (200 m), of amphibolite are entirely encased in serpentine. The schistosity and banding trends north-northeast – south-southwest parallel to the general trend and schistosity of the other metamorphic rocks in the area. It forms the easternmost outcrops of the basic igneous-volcanic massif of the Sierra del Purial and is in fault contact with the metasediments of the Sierra Verde Formation to the east in the Asuncion area. The age of the Gu ¨ ira de Jauco Formation is unknown. A K-Ar age determination has given 72–75 Ma, or Campanian–Maastrichtian, which could be the age of the metamorphism. However, zircon from a sample of gabbro-amphibolite has given 100 ± 50 m.y., suggesting that the original rock could be much older. La Farola Formation. — This name is another wastebasket unit that includes all the metavolcanics of the Sierra del Purial. It is synonymous with the Purial complex of Milla´n and Somin (1985a, b) and Millan-Trujillo (1996), who divided it into five sequences, which are, from east to northwest, Rio Baracoa, Jojo, Quivican, Via Mulata, and Mal Nombre. Although Milla´n and Somin consider this term invalid because it includes a number of disparate lithologies, it is used in this book as a group since it is shown on the 1988 geologic map (Pushcharovsky et al., 1988).

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FIGURE 139. Stratigraphic section: Purial massif metamorphics, eastern Cuba, southeastern Oriente.

Rio Baracoa sequence. — The unit (named by Milla´n and Somin, 1985a) outcrops in the easternmost part of the Purial massif and consists of a mostly sedimentary section. It is a dominantly basic pyroclastic section, sometimes effusive but with common polymict sandstones, quartz feldspar sandstones, and limestones.

The primary composition of the pyroclastics is effusive with abundant tuffs showing graded bedding. The recrystallization is uneven, and the highest grades show albite, chlorite, epidote prehnite, and actinolite and, more rarely, lawsonite, glaucophane, and pumpellyite.

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The polymict metasandstones are dark gray and poorly bedded, and the clasts are deformed. They contain abundant fragments of intermediate to basic feldspars, clinopyroxenes, and clasts of basalt and andesitic basalt. Frequent fragments of a fine-grained aggregate of sericite, quartz, and albite might have originated from a dacitic effusive rock. Abundant grains of hornblende, quartz, epidote, and oxides, with the plagioclase, might have originated from the erosion of a diorite or quartz-diorite. The common metamorphic minerals are chlorite, actinolite, epidote, sericite, albite, and rarely, glaucophane. In places, groups of beds of quartz-plagioclase metasandstones contain fractured clasts of quartz and acid plagioclase that appear to have been derived from granitoids. The common metamorphic minerals are chlorite, epidote, sericite, lawsonite, and rarely, glaucophane. Limestones occur quite frequently and form beds from 2 in. (5 cm) to ±6 ft (±2 m). They are crystalline, light colored, well bedded, and seldom massive. They are interbedded with the metasandstones and metatuffs. The following fossils have been found: Sulcoperculina globosa*, Sulcoperculina diazi*, Lepidorbitoides sp.*, Pseudorbitoides sp., Orbitoides cf. tissoti*, Globotruncana cf. elevata, Globotruncana linneana, Globotruncana arca, Globotruncana lapparenti, Globotruncana cf. calcarata, Globigerinelloides sp., and Hedbergella sp. (the asterisk indicates that the fossils were found in a float believed to belong to the Rio Baracoa sequence), suggesting a late Santonian–Campanian age. This sequence is unconformably overlain by the massive, barely recrystallized limestones of the Can ˜ as Formation (named by Colbiella et al., 1984) containing Orbitoides apiculata, Pseudorbitoides rutteni, Lepidorbitoides sp., and Sulcoperculina globosa. This fauna is interpreted as Maastrichtian. The Can ˜as Formation is not shown in Pushcharovsky et al. (1988), and it is believed to be a postmetamorphic and postultrabasic thrust plate overlap; the field relationships are not clear. It should be noted that the age difference between the limestones attributed to the Rio Baracoa sequence and the Can ˜ as Formation is not obvious from the fossil list alone. Jojo sequence.—The Jojo sequence (named by Milla´n and Somin, 1985a) outcrops on the south-central slopes of the Purial massif and is characterized by pyroclastic rocks of a basaltic composition. Pyroclastics and effusive rocks of andesitic and rhyolithodacitic composition are also present. Polymict medium-grained metasandstones with volcanic fragments and quartz are observed, possibly

derived from the erosion of granitoids. In addition, some isolated groups of beds of fine-grained actinolite schists, in places rich in graphite, containing albite, quartz, chlorite, and glaucophane. This sequence shows similarity to some of the lithologies of the unmetamorphosed Bucuey (Santo Domingo) Formation of the Cabaiguan* sequence. Loma quivican sequence. —The Loma Quivican sequence (named by Milla´n and Somin, 1985a) outcrops in the north-central part of the Sierra del Purial and consists of nonmetamorphic to slightly metamorphosed volcanics. The metamorphism is so low that the volcanic glass is unaltered. The major lithologic type consists of psammitic tuffs and poorly bedded tuff breccias made of fragments of plagioclase basalt, amygdular porphyritic andesite basalts, fragments of clinopyroxene crystals, and magmatic plagioclase. Between these tuffs are intercalations of very finegrained, commonly schistose tuffs with bands of various colors. The effusive rocks constitute 25% of the total and are represented by porphyritic basalts with low TiO2 and K2O and high alumina that is characteristic of tholeiites. Via Mulata sequence.—The Via Mulata sequence (named by Millan-Trujillo, 1996) outcrops in the northwestern part of the Sierra del Purial complex and consists of a sequence of well-bedded metatuffs showing rhythmic sedimentation. Medium- to finegrained tuffs can be recognized, and the color varies from green to lilac with a slaty luster. Occasionally, light-colored slaty limestones occur. This sequence could represent a lateral equivalent of the Loma Quivican. Mal Nombre sequence. —The Mal Nombre sequence outcrops in the extreme northwest of the Sierra del Purial complex and consists of homogeneous, massive to poorly bedded, polymict metasandstones. In general, they are poorly sorted, angular, and coarse grained up to brecciated metaconglomerates. The clasts vary much in size and, in general, are flattened and elongated. Occasionally, very fine-grained layers are present. This sequence is similar to some of the clastics of the Rio Baracoa and could be a metamorphic equivalent of the Mı´cara Formation as well as La Picota Member of the Cabaiguan* sequence. This complex is very likely the metamorphosed equivalent of the Cretaceous volcanic arc sequence and its ultrabasic basement that characterizes the Cuban basic igneous-volcanic province. It is the only place in Cuba where this section is metamorphosed. The metamorphism, characterized by glaucophane,

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is of the high-pressure–low-temperature type and decreases from southeast to northwest. This complex is highly deformed. Based on a window near La Tinta, it is believed by Cobiella et al. (1984) to form a relatively thin thrust sheet overriding its unmetamorphosed equivalent, the Bucuey (Santo Domingo) Formation. For this reason, the thicknesses cannot be estimated, and a section is impossible to reconstruct. However, it is quite probable that the Gu ¨ ira de Jauco Formation was the oceanic basement under the volcanic section, and the Mal Nombre sequence might have been the highest volcanic unit over or partly equivalent to the Rio Baracoa sequence. By similarity with other volcanic section, the La Farola Formation may extend from the Aptian(?) through the Maastrichtian. Granitoids.— Pushcharovsky et al. (1988) show a body of Upper Cretaceous quartz diorite in fault contact with the Rio Baracoa and/or the Jojo sequences. Note. —An assemblage of serpentinites, leucocratic gabbros, and diabases altered with a fine aggregate of epidote, chlorite, albite, prehnite, and actinolite is in fault contact with the encasing rocks (Gu ¨ ira de Jauco to the east and La Farola to the west) and has a general north-northeast–south-southwest trend. To the north of this belt of outcrops are large blocks of serpentine and gabbros: the serpentinites contain inclusions of high-pressure metamorphics. To the southwest of the ultrabasics, infaulted in the Rio Baracoa sequence, are conglomerate-breccias containing rounded blocks of serpentinite and diabase in a disintegrated serpentine matrix. They appear to be allochthonous, and although no other material was found, they are similar to the Maastrichtian Picota conglomerates to the north and west. Consequently, these ultrabasics do not belong to the metamorphic province, but are part of the overlying Maastrichtian–Paleocene ultrabasic Mayari-Baracoa thrust sheet. In southwestern Oriente are some poor outcrops of metamorphosed volcanics underlying the Cobre Formation. Tejas Formation. — The Tejas Formation consists of poor outcrops, near Santa Rita, of light-gray, tuffaceous, micaceous schists. It consists of quartz, sericiteillite, and pyrite. Several andesite dikes belonging to Cobre Formation cut this formation. The original rock is believed to have been a tuff. No fossils have been found, and the Tejas Formation is believed to be unconformably under the Cobre Formation. It is probably equivalent to part of La Farola Formation of the Purial massif.

Purial Massif Metamorphics Discussion. — The Purial massif sequence represents a metamorphosed Domingo*–Cabaiguan* sequence section with some affinity to the Manicaragua belt (Mabujina amphibolite), but with a greater development of volcanics. According to Millan-Trujillo (1996), it shows low-grade high-pressure – low-temperature regional metamorphism. The contact between the metamorphics and the main body of ultrabasics to the north and south is by faults, with the ultrabasics riding as a sheet over the Purial massif anticlinorium. The ultrabasics are not metamorphosed and could have been thrusted from south to north. The La Farola Formation metamorphics are also considered by Cobiella et al. (1984) to be a thrust sheet riding over the equivalent unmetamorphosed Bucuey (Santa Domingo) Formation, although they admit the possibility that the window of Bucuey Formation could be an olistolith, or a tectonic scale, under the ultrabasics. The relation between the metavolcanics of the Purial and the Asuncion metamorphics is tectonic and further confused by the presence of ultrabasics. However, the band of ultrabasics separating the metamorphosed Cabaiguan* sequence from the Gu ¨ ira de Jauco amphibolites is believed to be part of the major ultrabasic Mayari-Baracoa thrust sheet that formerly covered the Purial massif and was wedged along the faults that separate the Purial from the Asuncion area. It is no coincidence that in central and western Cuba, amphibolites (Mabujina, Daguilla) are also found in contact with metamorphosed sediments, suggesting that the Asuncion area was originally part of a window of metamorphosed sediments showing through the thrust sheet of amphibolite basement under the Purial metavolcanics. The original prethrusting width (if such thrusting occurred) represented by Domingo* belt and the Purial metamorphics must have been at least 100 km (62 mi).

Eastern Cuba: Basic Igneous-Volcanic Terrane Discussion Oriente, like the other Cuban regions, does not show a complete stratigraphic sequence of any particular province, but presents a different look at a particular phase of the geological development of the island. Only three provinces are exposed: (1) the carbonate platform, (2) the basic igneous-volcanic, and (3) the metamorphic. The platform to deep basin province is not exposed, which does not mean that it is not present at depth.

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The basic igneous-volcanic province can be seen, from north to south, in four different structural situations: 1) Tightly compressed against the carbonate platform, where the ultrabasics form the basement under the Albian–Turonian volcanics and were thrusted over them in the Campanian–Maastrichtian. 2) Relatively undeformed, where the ultrabasics, covered with Maastrichtian and Paleogene sediments and volcanics, form the nearly horizontal Mayari-Baracoa thrust sheet over the unmetamorphosed Albian–Turonian volcanics (considered autochthonous). 3) Relatively undeformed and unmetamorphosed ultrabasics of the Mayari-Baracoa thrust sheet covering highly deformed and slightly metamorphosed greenschist formed from the Upper Cretaceous volcanics, possibly, according to Cobiella et al. (1984), the same thrust sheet that overlies the equivalent unmetamorphosed section. 4) Moderately deformed, very thick section of Paleocene to middle Eocene volcanics, possibly overlying unmetamorphosed and metamorphosed Upper Cretaceous (pre-Campanian to Maastrichtian?) volcanics. In all situations, there is indication of volcanism in the lower – middle Eocene. Very little can be said about the stratigraphy and basement of the Cretaceous Cabaiguan* sequence except that the section is mostly post-Albian to preCampanian and tends to be basic to intermediate in composition. Based on other Cuban regions, the basement is assumed to have been the basic to ultrabasic complex. During the Campanian in northern Oriente and Maastrichtian in southeastern Oriente, the volcanics were covered with a thrust sheet, or cold extrusion and flow, of the ultrabasic complex. After the emplacement of the thrust sheet, the overlying Cretaceous volcanics, if present, were eroded, and sediments were deposited over both the ultrabasic thrust sheet and/or the underlying Cretaceous volcanics. This occurred in the Campanian to middle Eocene in northern Oriente and Maastrichtian to middle Eocene in southeastern Oriente. There is no indication of ultrabasics in southwestern Oriente. The direction of thrusting is problematic; in northern Oriente, it was very probably directed northward, but in eastern Oriente, it could have been directed either north or south. The northwest – southeast-

trending 180-milligal Bouguer gravity anomaly (the largest in Cuba, which otherwise is characterized by relatively low gravity values) located under the MayariBaracoa massif and coinciding with the Moho high (diapir?) indicated by the crustal measurements (see Chapter 5, this publication) suggests a shallow oceanic basement. Possibly under tension, the serpentinized ultrabasics might have moved upward and flowed horizontally over the unmetamorphosed, as well as already metamorphosed, volcanics. This sheet, or flow, could have moved southward, although Cobiella et al. (1984) consider the movement to have been northward. A second strong and parallel gravity high, reaching 140 milligal, coincides with the eastern end of the regional southwestern Oriente high and the Bayamo– San Luis depression. The outcrops show no obvious reason for this feature, which is a good evidence for a deep-seated origin. A marked increase in the amount of volcanics and volcaniclastics from north to south during the Paleocene to middle Eocene is observed. Lower–middle Eocene ashes are reported from northern and western Cuba, but in small quantities. These volcanics are the result of the large lower–middle Eocene intermediate to acid, volcanic center in the southwestern part of eastern Cuba characterized by the Cobre Formation and related units. This center could have been related to the Jardines de la Reina archipelago’s northeastdipping subduction zone. At any rate, this is proof that in Oriente volcanism continued after the obduction of ultrabasics and, simultaneously, with the violent deformation that was occurring along the Cuban axial thrust zone to the north and west. The relationships between the La Farola volcanics, the Gu ¨ ira de Jauco amphibolites, and the Asuncion complex are obscured by high-angle faults. However, like the Mabujina amphibolite in the Escambray massif, the Gu ¨ ira de Jauco is believed to be the basement over which the La Farola metamorphosed volcanics were deposited. In addition, as in the Escambray massif, both overrode the nonvolcanic sediments, in this case, the Asuncion metamorphics. Note the following: 1) The dating of the amphibolite metamorphism is Campanian–Maastrichtian, whereas the amphibolite itself could be Lower Cretaceous or older. 2) The overlying metamorphosed Rio Baracoa sequence is Campanian. 3) This metamorphic sequence is under the unmetamorphosed Mayari-Baracoa ultrabasic thrust sheet that is, in its turn, covered by unmetamorphosed Maastrichtian sediments.

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Apparently, the metamorphism preceded the thrusting of the ultrabasics that occurred in the Maastrichtian. However, because the Asuncion complex is metamorphosed, the thrusting of the amphibolites over it must have preceded or been simultaneous with the metamorphism, meaning Campanian at the latest. In this area, along the coast, evidence exists for northward-directed thrusts of the serpentine and lower – middle Eocene Cobre Formation over the late middle Eocene to lower Oligocene San Luis Formation; they appear to originate in the Cayman trough. These movements could be related to the early development of the Cayman rift; this will be described in Chapter 3 of this publication. These conclusions about timing and mechanism of the orogenic process fit well and complement the conclusions derived from other areas: 1) They agree with the Upper Cretaceous metamorphism and simultaneous deformation of the entire Cuban arc. 2) They support the timing of the original deformation of the ultrabasics; the first ultrabasic detritus is found in the Maastrichtian of the miogeosyncline Amaro* and Cacarajı´cara formations. 3) They support the evidence indicating that the ultrabasic basement was of a rifted nature, and although it served as basement for a volcanic sequence, much of it was never subducted under a continental margin. 4) The age of the first appearance of igneous detritus in sediments supports the evidence that the deformation of the ultrabasics and volcanics proceeded at different times in different areas of the Cuban geosyncline as indicated by the following ages, progressing from earliest in the south to latest in the north: Campanian: Moreno (northern Rosario) Maastrichtian: Cacarajicara (southern Rosario), Amaro*, (Cifuentes*) Paleocene: Anco´n (Sierra de los Organos) early –middle Eocene: San Martin* (Las Villas* and Yaguajay*), Embarcadero (Yaguajay*) 5. The possible obduction of ultrabasics and volcanics over the nonvolcanic sediments was not responsible for the metamorphism of the southwestern terrane. 6. Eastern Cuba, like western Cuba, confirms the presence of a strongly compressed and deformed axial zone between the carbonate platform to the north and an area to the south characterized

by skin tectonics with large nappes, thrusts, or slides, which adjoins the Cretaceous arc farther to the south. Not much information exists to determine the distribution of facies within each province of eastern Cuba; however, what there is provides information about their relationships. As in the other regions, two possible alternatives exist: (1) the basic igneous-volcanic province was originally south of the Sierra del Purial and Asuncion metamorphics and (2) the basic igneous-volcanic province was originally north of the Sierra del Purial and Asuncion metamorphics. The first alternative is the more likely. This reconstruction is supported by the similarity between the Asuncion complex and the carbonate platform to deep-water province sediments. However, the presence of the nearly horizontal ultrabasic thrust sheet above the relatively undeformed volcanic arc as well as above the metamorphosed volcanics is difficult to explain with this interpretation. If the Domingo* and Cabaiguan* sequences, which are highly deformed in northern Oriente but nearly horizontal in southeastern Oriente, are part of the same thrust over the metamorphics, then the thrusting alone cannot explain the northern Oriente deformation. The metamorphosed La Farola, which shows a northward decrease in metamorphism, is possibly thrusted over and is the equivalent to the Bucuey (Santo Domingo, Teneme) volcanics. Therefore, two sources of regional metamorphism, one for the Purial complex and another one for the Asuncion complex, are required to explain this reconstruction. The northern part of the southwestern Oriente Paleogene volcanic complex overlies metamorphosed volcanics, possibly equivalent to La Farola Formation. To the south, however, along the south flank of the Sierra Madre, unmetamorphosed Cretaceous volcanics are present. In view of the fact that this lower– middle Eocene volcanic activity occurred after the deformation and thrusting of the basic igneousvolcanic province and synchronously with the paroxysm of deformation along the main Cuban thrust belt, it is believed to be nearly autochthonous (over the already thrusted Domingo* and Cabaiguan* sequences), although together with serpentines, it has been found thrusted over the middle–upper Eocene San Luis Formation south of the Sierra del Purial. The effect of this volcanism was felt over most of eastern Cuba, as indicated by the tuffs in the Paleogene of northern and southeastern Oriente.

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FIGURE 140. Restored stratigraphic section, central Cuba, north-central terrane (through Gulf Blanquizal III-1).

DISCUSSION OF THE PRE–UPPER EOCENE STRATIGRAPHY OF CUBA In this section, an attempt will be made to piece together some of the most significant, previously described stratigraphic components. This will have to be done for each area and assembled for the entire island. Because the stratigraphic details for each component have been discussed earlier in this chapter, this section will concentrate on how the different components can be pieced together, in essentially a two-dimensional model, based only on central Cuba stratigraphic evidence. The possible model will be geographically expanded later as other areas are described. In all the restored stratigraphic sections, the top of the Cretaceous will be used as datum. The datum will be shown at the estimated subsea depth for that time, the rock thicknesses (measured or estimated) will be shown below the datum, and the distances will be palynspastically restored according to the already given estimates of shortening. For the sake of graphic clarity, it will be assumed that major shortening had not occurred until the end of the Cretaceous, which, of course, is not entirely correct. For the same reason, the lithologic symbols will be simplified. Although the models are two-dimensional, the four segments of each section were not neces-

sarily located along what was then a continuous profile; there may have been considerable transcurrent displacement between them as well as rotation of some of them.

North-Central Terranes: Carbonate Platform to Deep Basin Section Although there has been some shortening, this is the most autochthonous of the three subbasins. Two possible lines of section exist from the Bahamas platform to the deep-water basin: (1) Cay Sal-1, Blanquizal-1, Yaguajay* belt, Sagua la Chica* belt, and Las Villas* belt; and (2) Cay Sal-1, Cayo Coco-2, Yaguajay* belt, Jatibonico* belt, and Las Villas* belt (see Figures 140, 141, respectively). These sections show the distribution of lithologic types at the end of the Cretaceous. There were some local reef developments at the edge of the Jurassic–Cretaceous bank, but typical reef rocks have not been observed in place in central Cuba, although reef debris is very common in the Las Villas* belt carbonate clastics. The Maastrichtian Mayajigua* Formation conglomerate consists almost entirely of reef fragments. The reefs may be present at depth and not exposed because of the geometry of the south-dipping Yaguajay* belt fault block, which shows only the bank (backreef) facies. It should also be noted that most of the exposed Jurassic represents bank conditions; only

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FIGURE 141. Restored stratigraphic section, central Cuba, north-central terrane (through Shell Cayo Coco-2).

the Tithonian Caguaguas* Formation in the Las Villas* belt shows a deepening of the waters with an influx of pelagic organisms. From the late Early Cretaceous on, there appears to have been carbonate banks separated from the main Bahamas Bank by deep, open-water tongues. The sections through the Cayo Coco –Punta Alegre areas show this. The southeastern part of the Yaguajay* belt appears to have been one of these isolated banks. This is further supported by the presence of Casablanca Group outcrops north of the Upper Cretaceous Remedios Formation in the Sierra de Cubitas; this situation could have extended much farther west. Also of interest is the evidence for a separated Early Cretaceous basement high, named Rana, south of the main Bahamas Bank.

Southwestern Terranes: Carbonate Platform to Deep Basin Section The main difference between western Cuba and central Cuba is the lack of a well-established, and incontrovertible, Cretaceous and later continental margin such as the Bahamas Bank and the development of a thick Jurassic sand-shale section. The other major difference is that, generally speaking, the belts of central Cuba are dipping to the south, toward the Seibabo syncline with a southward progression from shallowwater to deep-water sediments and, finally, volcanics,

whereas in western Cuba, the situation is reversed. The dips are generally northward, and the shallower water sediments to volcanic succession of belts is from south to north toward the Mariel-Matanzas synclinorium. Amazingly, to this date, no published direct evidence of the direction of thrusting exists, so there have been arguments for either direction of motion. For any number of regional considerations, it is very difficult to visualize a north-to-south direction of thrusting in western Cuba. If one assumes that the basic igneous-volcanic complex constitutes the highest of the thrust sheets and originated from the south, then the sequence of belts becomes (from north to south) Mogotes, southern Rosario (east), northern Rosario, and Guajaibon – Sierra Azul belts (see Figure 142). It is postulated that the Guajaibon-Cierra Azul bank carbonates were deposited over a western continuation of the Rana high, south of the northern Rosario deep-water sediments. This paleohigh could have been responsible for the Cretaceous section being sandier westward. This is shown in a second profile, Figure 143 that, from north to south, displays the Mogotes, southern Rosario– Alturas de las Pizarras del Sur area, Cangre, and La Esperanza belts. This succession will be used herein as the most logical, but not necessarily the only alternative. It must be noted that the metamorphism of the Cangre belt can be definitely dated as early Tertiary.

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FIGURE 142. Restored stratigraphic section, western Cuba, southwestern terrane, eastern section. Upper portion shows Guajaibon to the north; lower section shows Guajaibon to the south.

Metamorphic Province: Escambray Two possible ways of restoring the stratigraphy across the massif exist, depending on the direction of internal thrusting. Figure 144 will show the section assuming that the thrusting is from south to north. If the thrusting were from north to south, it would be the mirror image of the first case. The fact that three distinct metamorphic grades corresponding to groups of thrust sheets can be distinguished indicates that the thrusting occurred mostly after the metamorphism. Furthermore, the metamorphism of the southwestern terrane is not directly related to the Manicaragua granodioritic intrusion (median age of 78 m.y.), which is limited to the vol-

canic sequence. However, some late metamorphism, like in the Cangre belt, might be the result of the obduction of the Domingo sequence. This is supported by the distribution of radiometric age of metamorphism with a peak in the Upper Cretaceous and a median of 66 m.y. The shown thicknesses are only for the purpose of illustrating the facies relationships; only vague estimates are available.

Metamorphic Province: Isla De La Juventud It is impossible to deduce any sedimentary trend from the published data on the outcrops of the Isle

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FIGURE 143. Restored stratigraphic section, western Cuba, southwestern terrane, western section.

FIGURE 144. Restored stratigraphic section, central Cuba, southwestern terrane, Escambray Massif.

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FIGURE 145. Restored stratigraphic section, central Cuba, basic igneous-volcanic terrane.

of Pines. Presently, the northern half of the metamorphic massif has higher metamorphic grades than the southern one. As previously discussed, whatever is the reason for the reverse metamorphism, the higher metamorphic grades only indicate closer proximity to the obducted crust.

Basic Igneous-Volcanic Terrane Sections North-Central Cuba This section is a composite of Las Villas (north flank) and Camaguey (south flank) provinces that represents a cross section of the terranes. It is shown in Figure 145. In relation to these sections, it should be remembered that the thicknesses in the Domingo* sequence are estimated.

Southwestern Cuba Rocks from this province are not well represented in this part of Cuba, so the restored cross section will be based, from north to south, in only three sections; Bahia Honda area; southern tectonic unit, Bahia Honda area; and northern tectonic unit and Los Palacios Basin. The width will be arbitrarily set at 250 km (155 mi) (see Figure 146).

Northern Cuba In northern Cuba, it is not possible to develop a stratigraphic model because of the limited information provided by outcrops or drilling. However, the following points can be definitely established: 1) Four groups of stratigraphic units have been identified: Las Villas* and Cifuentes* belts, and Domingo* and Cabaiguan* sequences. 2) From the northeast to southwest or from the well bottom up, the groups of units occur in the abovedescribed succession, proving the validity of the concept that northern Cuba, as well as central Cuba, is made up of a stack of thrust sheets each representing a characteristic section of a major geosynclinal basin. However, as indicated by the well EPEP Vegas-1, the regional slope of the base of the Domingo*–Cabaiguan* thrust sheet is at least 1 in 8 km (5 mi) to the south. 3) No well in northern Cuba has penetrated rocks of the Yaguajay* belt, although penetration as deep as 16,500 ft (5000 m) is common. This suggests that onshore, the Bahamas-type carbonate bank does not extend farther west than Cardenas Bay (more exactly, between Gulf Hicacos-1 and Gulf

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FIGURE 146. Restored stratigraphic section, western Cuba, basic igneous-volcanic terrane.

Blanquizal III-1) and then crosses the present-day Florida Strait to the edge of the west Florida shelf. 4) The outcrops of Domingo* and Cabaiguan* sequence rocks are continuous through northern Cuba, indicating that these belts in western Cuba belong to the same basic igneous-volcanic province as those of central Cuba. 5) Although volcanic ejecta are found in strata as young as the lower – middle Eocene, no major volcanic deposits exist above the base of the Campanian–lower Maastrichtian Via Blanca Formation. After the accumulation of most of the volcanics, the pre–Via Blanca volcanics were subject to strong deformation, erosion, and redeposition in what appears to have been submarine topography with great relief. This period represents the beginning of the destruction of the Cretaceous volcanic arc, and according to some sedimentary patterns, the source of sediments was to the south. Possibly, it was the time of the initial northward thrusting of the basic igneous-volcanic province. 6) The final emplacement of the basic igneousvolcanic thrust sheet, as well as the stacking of the carbonate thrust sheets occurred, as in the rest of Cuba, during the early–middle Eocene. In many

places, a marked unconformity exists between the middle and upper Eocene; however, in some areas, a perfectly conformable transition is present.

Eastern Cuba In eastern Cuba, the information available about each province provides only a stratigraphic section with no lateral variation. Furthermore, no reliable reported thicknesses occur. The angularity between the regional Cuban trends and the Cayman trough makes simple north – south reconstructions unrealistic. Lateral motions and rotations are certainly involved. Although the model used for other parts of Cuba probably generally applies, no restored cross section will be attempted for eastern Cuba.

Restored Cuba Cross-Sections Restored cross sections can be put together for central and western Cuba to give a general idea of the pre– upper Eocene facies distribution (see Figure 147). It must be noted that the original width represented by the present outcrops could approximate 1000 km (621 mi).

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FIGURE 147. Restored stratigraphic section, central and western Cuba.

3

Pardo, G., 2009, Post – middle Eocene stratigraphy, in G. Pardo, The geology of Cuba: AAPG Studies in Geology Series, no. 58, p. 277 – 293.

Post–middle Eocene Stratigraphy An important difference exists between the upper Eocene (and later) sediments along the north-central coast of Cuba and those found along the southern part of the island, mostly covering the Cabaiguan* sequence. Along the north-central part of the island, the upper Eocene, and later, sediments are in marked unconformable contact with the older rocks, whereas along the southern half of Cuba, they overlie the Cabaiguan* sequence and show a transition with no definite break between the middle and the upper Eocene. A correlation chart of the post–middle Eocene is shown in Figure 149. Many of the post– upper Eocene lithologic units are local with restricted geographic distributions; a graphic columnar section has been prepared only when a thick continuous section is known to exist such as the Los Palacios and Guanacayabo-Nipe basins. In view of the fact that Cuba was almost completely emergent by the end of the Miocene, only the upper Eocene to lower Pliocene formations will be described; the Pliocene and Pleistocene stratigraphic units are local, thin, and discontinuous and, therefore, irrelevant for the purpose of this report.

At the close of the middle Eocene, most of the strong orogenic deformation in Cuba had occurred, and the general distribution of the pre–upper Eocene structures and stratigraphic units was essentially as it is now. The younger Tertiary sediments began to accumulate over the now-essentially inactive, largely peneplained, submarine mountain chain, reflecting some large-scale deformation that included folding and faulting. The overall movements during the remainder of the Tertiary have been of a slow, continuous uplift, with much of Cuba emerging by the Miocene. The younger Tertiary sedimentation consisted mostly of the filling of topographic depressions, although erosion of uplifts and filling of subsiding areas also occurred. It should be noted that Gulf Oil, with the exception of a few areas in central Cuba, did little work on the younger Tertiary; therefore, much of the following is derived from published information, namely, Iturralde-Vinent (1977, 1988), Jakus (1983), and Fernandez et al. (1987). As shown in Figure 148, the post –middle Eocene will be described according to the following areas: Northern coast = Havana to Oriente Provinces Southwestern basin = Los Palacios Basin, HabanaMatanzas, and western Las Villas South-central basin = Central Depression (Gulf of Ana Maria) Southeastern basins = Guanacayabo-Nipe Basin, central syncline, Guantanamo depression, and southern coast (only the stratigraphic unit of the Oriente southern coast will be listed).

NORTHERN COAST This region extends along the north coast of Cuba from Matanzas to Oriente and includes the outcrops of rocks of upper Eocene age associated with the Coastal*, Yaguajay*, Las Villas*, and other sedimentary belts to the north of the Domingo*-Cabaiguan* sequence front. No complete section in wells or outcrops exists.

A characteristic of most upper Eocene and later sediments is their richness in fossils, mostly large and small foraminifera. They are a paleontologist’s paradise. Consequently, for the sake of brevity in this report, only characteristic species will be mentioned.

Piedras* Formation The Piedras* Formation consists of 440 ft (134 m) of white to light-gray, dense foraminiferal coquina.

Copyright n2009 by The American Association of Petroleum Geologists. DOI:10.1306/13141062St583328

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FIGURE 148. Cuba post – middle Eocene basins.

The limestone is fairly clean, with only occasional marly and slightly sandy beds. Discocyclinas, asterocyclinas, and lepidocyclinas characterize the fauna. The age is considered upper Eocene. It lies unconformably over the Vega Formation and older rocks of the Yaguajay* belt.

Rancho Bravo Formation The Rancho Bravo Formation consists of 200 ft (60 m) of polymictic hard, dark green, calcareous conglomerates with well-rounded clasts of ultrabasics, making up to 60% of the total rock. This conglomerate is poorly sorted, with pebbles up to 4 in. (20 cm) in diameter. Clasts of limestones from the Gibara area also exist. Above the conglomerates are beds of finegrained, gray, argillaceous sandstones and hard beige mudstones. A fauna of nannoplankton indicates middle to upper Eocene age. Reworked middle Eocene and Upper Cretaceous foraminifera exist. This formation, present in northern Oriente, is equivalent in age to the San Luis Formation and lies unconformably over the Vigı´a Formation.

Chambas* Formation The Chambas* Formation consists of 2700 ft (820 m) of yellow-brown, calcareous sandstones and conglomerates with abundant beds of sandy limestone, cavernous organic limestone, marls, and clays. The con-

glomerates contain abundant igneous fragments. The formation is medium bedded. The Chambas* Formation contains abundant mollusks and is characterized by large lepidocyclinas (in part stellate forms with spatulate equatorial chambers). The age is considered lower–middle Oligocene. Some middle Eocene faunas, found in the lower part, are probably reworked. In outcrop, this unit has been recognized only in the eastern rim of the Jatibonico Mountains, where it seems to unconformably overlap with the upper Eocene Piedras* Formation and the lower–middle Eocene Vega* Formation. It has been identified in Punta Alegre-2, where it is 636 ft (194 m) thick, and overlies the Turiguano* Formation.

Gu¨ines Formation The Gu ¨ ines Formation consists of an unknown thickness, but is probably quite thin, of locally dolomitized, cavernous, organic, reefoidal limestones. It also contains some dirty marls and sandstones. It was named by Alexander Von Humboldt in 1826, thus being one of the oldest formation names in the Caribbean. The fauna is characterized by very abundant mollusks, corals, and algae. Amphisorus sp. and Amphistegina sp. are the characteristic foraminifera. It is of Miocene age. In most places, it is fairly flat lying or tilted with gentle dips. It occurs along the flanks of major structures and makes up the greatest part of the

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FIGURE 149. Correlation chart, upper Eocene – upper Miocene.

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surface of the coastal belt. This formation is extensively developed from northern to eastern Cuba and is unconformable on all older units of the Yaguajay*, Las Villas*, Placetas*, and Cifuentes* belts.

Vasquez Formation The Vasquez Formation (named by P. Jakus in 1974) consists of more than 650 ft (200 m) of well-bedded, cream to green-gray limestones, marls, and clay. The limestones are commonly bioclastic. The clays are bentonitic and are locally interbedded, with layers of lignite and gypsum, indicating a restricted lagoonal environment. The fossils include mollusks, foraminifera, and ostracods. Among the foraminifera, Ammonia beccarii, Amphisorus hemphrichi, Amphisorus matleyi, Amphistegina angulata, Archaias angulatus, Asterigerina subacata, Clavulina tricarinata, Discorbis cercandensis, Discorbis subaraucana, Elphidium chipolensis, Elphidium poeyanum, Elphidium rutteni, Elphidium sagrai, Eponides byramensis, and Quinqueloculina byramensis have been identified, indicating a middle Miocene age. It lies unconformably over all the older formations of northern Oriente.

Unnamed Upper Eocene In the well Kewanee Collazo-1, 2220 ft (677 m) of an unnamed upper Eocene section has been penetrated. It consists of soft to hard, dense to coarsely detrital, in part bituminous, limestones and marls showing incipient dolomitization. The section is porous and very fossiliferous.

Unnamed Oligocene In the well Kewanee Collazo-1, 365 ft (111 m) of an unnamed Oligocene section has been penetrated. It consists of two intervals of red silt, bedded or nodular anhydrite, and some inclusions of dolomite separated by a white, dense to fine-grained, soft to hard, fossiliferous marly, Lepidocyclina spp.–bearing limestone. The anhydrite does not resemble anhydrite found higher in the well or in the Punta Alegre outcrops. Spores and pollen analyses have given a lower Oligocene age for the silts. The limestone has also been dated Oligocene on the basis of microfossils. It should be noted that on the Loma Cunagua, outcrops of pure white gypsum are interbedded with marls and limestones that yielded a Miocene fauna. It therefore appears that in the Punta Alegre–Loma Cunagua area, a little known Oligocene–Miocene basin contains evaporites. Whether it is a true evaporite basin or the evaporites were derived from the nearby diapirs is unknown.

Drilling Of the wells drilled along the north coast, the following have penetrated an appreciable section of upper Eocene and younger sediments: ICRM Colorado-1: Drilled ±2360 ft (±720 m) of Neogene limestones Gulf Hicacos-1: Drilled 2290 ft (698 m) of upper Eocene limestones and Cojimar(?) Formation ICRM Cayo Fragoso-1: Drilled ±2300 ft (±700 m) of Oligocene and Neogene limestones ICRM Cayo Frances-5: Drilled ±2790 ft (±850 m) of upper Eocene, Oligocene, and Neogene limestones Kewanee Collazo-1: Drilled through 2331 ft (711 m) of upper Eocene and Oligocene limestones, marls, siltstones, and gypsum (see above) Shell Punta Alegre-2: Drilled 3548 ft (1082 m) of Chambas* Formation and Neogene EPEP Moron Norte-1: Drilled ±2790 ft (±850 m) of upper Eocene, Oligocene, and Neogene clastics.

SOUTHWESTERN BASINS These basins are part of a late to postorogenic basin that started to develop while the thrusting was in its final phase. In places, the sediments filled depressions on the surface of the basic igneous-volcanic province, where the sedimentation continued uninterruptedly from middle Eocene into the upper Eocene. In other areas, topographic highs were actively eroded, and marked unconformities developed. These basins are the Los Palacios Basin south of the Pinar fault, the Habana-Matanzas Basin, and the western Las Villas Basin. All three were probably part of one single basin.

LOS PALACIOS BASIN The extent of this basin is not well known, at least from the published data. Its northern rim is well defined by the Pinar fault; however, its southern rim is unknown. The rocks forming the bottom of the basin are questionable; the deepest penetration, Los Palacios-1, bottomed in Upper Cretaceous Cabaiguan* sequence sediments. A feature on the southern coast, called the La Coloma high, shows as a positive gravity and magnetic anomaly and is believed to be a basic igneous or volcanic high based on data from the drilling of ESSO Guanal-1A (or ESSO Guanal-2). Several wells have been drilled along what is believed to be the axis of the basin, and the most complete section of post – middle Eocene sediments has

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and is similar to the Jabaco Formation in the Bahia Honda area.

Guanajay* Formation The Guanajay* Formation (named by Truitt, 1956a) consists of 1475 ft (450 m) of very argillaceous limestones, fossiliferous marls, sandy and gravely limestones, polymictic sandstones, marls interbedded with organic sandy limestones, and conglomeratic gravels. This formation has been paleontologically subdivided into an upper Eocene interval characterized by the Globigerina ciperoensis – Globorotalia opima biozone and a lower Oligocene interval, of similar lithology, characterized by the Globigerina sellii – Globigerina ampliapertura biozone. Large foraminifera are characterized by Lepidocyclina undosa biozone. The environment of disposition is similar to that of the Eocene.

Paso Real Formation The Paso Real Formation consists of 1150 ft (350 m) of argillaceous limestones and marls with terrigenous material increasing with depth. Abundant planktonic foraminifera characterize the Globigerinoides primordium – Globorotalia kugleri biozone. In the more terrigenous part, abundant species of large foraminifera exist and Miogypsina sp. has been recognized. It is considered lower to middle Miocene age. Some nannoplankton are present in the lower part of the section with an increase in pelagic foraminifera. This unit outcrops along the Pinar fault.

Gu¨ines Formation

FIGURE 150. Stratigraphic section: post – Upper Eocene, Los Palacios.

been reported from the EPEP Candelaria-1 well. The section is shown in Figure 150.

Jabaco Formation The Jabaco Formation, named by P. J. Bermudez in 1937 (1950), consists of 755 ft (230 m) of interbedded polymictic conglomeratic gravels, sandstones, and fossiliferous argillaceous limestones. It has been subdivided into an upper Globorotalia cerroazulensis and a lower Globigerinatheka semiinvoluta zone. Larger foraminifera also exist that are characteristic of the Asterocyclina minima zone. The age is considered late upper Eocene. Deposition occurred in waters not deeper than 100 m (330 ft). This unit outcrops along the Pinar fault

The Gu ¨ ines Formation consists of 3936 ft (1200 m) of reefoidal organic and argillaceous limestones. Small benthic foraminifera, algal fragments, echinoderms, gastropods, and other mollusks characterize the fossils. Miliolidae, Peneroplidae, and Soritidae indicate deposition in shallow warm waters. The age is lower–middle Miocene, perhaps extending into the upper Miocene.

Drilling Many wells have been drilled in this basin, but not much data are available.

EPEP Candelaria-1 This is the deepest well reported in the basin. 1640 –5575 ft (500 – 1700 m) — Guines Formation. 5575–6724 ft (1700–2050 m)— Paso Real Formation. 6724–8200 ft (2050–2500 m)— Guanajay Formation (Ban ˜os). 8200–8955 ft (2500–2730 m)— Jabaco Formation. 8955 –14,379 ft (2730 – 4384 m) — Cabaiguan belt.

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ARCO Los Palacios-1A 0 to ±6560 ft (0 to ±2000 m)— Miocene and Oligocene. ±6560–8000 ft (±2000–8000 m)— Cabaiguan belt.

Shell Ariguanabo-2 0 to ±1738 ft (0 to ±530 m) — Miocene and Oligocene. ±1738 –10,030 ft (±530 –3058 m) — Cabaiguan* sequence.

ESSO Guanal-1A 0 to ±2820 ft (0 to 860 m)— Miocene. ±2820–3314 ft (860–980 m)— Cabaiguan* sequence.

HABANA-MANTANZAS This area is not a closed basin but a relatively thin wedge of younger Tertiary sediments, increasing in thickness southward.

Encanto Formation The Encanto Formation (named by Ducloz, 1960) consists of more than 130 ft (40 m) of marly limestones and yellow-cream marls. The formation is not well bedded, and the beds are medium in thickness. The fauna consists of pelagic foraminifera, including Globorotalia centralis, Globigerinatheka barri, Globigerina linaperta, Globigerina rohri, Globigerinita dissimilis, and Globorotaloides suteri. The age is considered upper Eocene. It is found with marked unconformity over the Universidad Formation.

Jabaco Formation The Jabaco Formation consists of less than 165 ft (50 m) of marls, irregularly stratified argillaceous limestones with intercalations, lenses, and blocks of foraminiferal, detrital, and conglomeratic limestones. The marls have a yellow to gray color and contain an abundant planktonic and benthic microfauna. The limestones contain, almost exclusively, large foraminifera and algae. It was named by P. J. Bermudez in 1937. Some of the characteristic fauna are Globigeria ampliapertura, Globigeria parva, Globorotalia cerroazulensis, Globigerinatheka barri, Hantkenina alabamensis, Hantkenina brevispira, Hantkenina mexicana, Hantkenina suprasuturalis, Discocyclina crassa, Asterocyclina marianensis, Asterocyclina georgiana, Coskinolina floridana, and Dictyoconus americanus. The age is considered late upper Eocene. It is equivalent to the Encanto Formation and to the upper part of the Nazareno Group.

Guanajay Formation The Guanajay Formation consists of 1150 ft (350 m) of an olistostrome where the matrix consists of gray and white, massive fine-grained marls with rare beds of medium-grained pink sandstones that contain clasts of Cretaceous rocks as well as olistoliths (from one to several meters in diameter) of gravels and conglomerates with calcareous cement and organic fragmental limestones containing lepidocyclinas, mollusks, corals, echinoids, etc. The sequence is broken by scales, or slump masses, obviously formed during the process of sedimentation. The fauna present in the marls consists of Globigerina yeguaenis, Globigerina rohri, Globigerina ampliapertura, Globigerina parva, Globigerina tripartita, Globigerina angulioficinalis, Globigerina venezuelana, Globigerina prasaepis, Catapsydrax dissimilis, Cassigerinella chipolenis, Globigerinita pera, Globorotaloides suteri, Globorotalia nana, Globorotalia opima, ostracods, and nannofossils. The gravels and limestones contain Heterostegina antillea, Nummulites sp., Gypsina globulus, Lepidocyclina favosa, Lepidocyclina undosa, Lepidocyclina duclozi, Amphistegina sp., and algae. The age is considered Oligocene. The Guanajay Formation was deposited in large part by gravitational slumping at the base of a slope.

Tinguaro Formation The Tinguaro Formation (named by Palmer, 1945) consists of some ±1000 ft (±300 m) of cream-colored, massive argillaceous marls. The fauna consists of Cassigerinella regularis, Globigerina praebulloides, Globigerina tinguarensis, Globigerina ciperoensis, Globigerina euapertura, Globigerina tripartita, Globoquadrina larmeui, Catapsydrax dissimilis, Globorotalia opima, and Globorotaloides suteri. The age is Oligocene, and it is equivalent to the Guanajay Formation. It lies unconformably over the Punta Brava and Nazareno formations. It was probably deposited in waters 500 m (1640 ft) deep.

Husillo Formation The Husillo Formation (named by Bro ¨ nnimann and Rigassi, 1963) consists of 130 ft (40 m) or less of bioclastic fine-grained limestones and subordinate argillaceous limestones. The beds are commonly massive and well bedded. The fauna includes Lepidocyclina sp., Miogypsina spp., Nummulites sp., Heterostegina antillea, Archaias cf. operculiniformis, Gypsina globulus, Acervulina inhaerens, Globigerinatella insueta, Globigerinoides bisphaericus, Globorotalia mayeri, Globoquadrina altispira, Gypsina dehiscens, Gypsina venezuelana, Globorotalia barisanensis, Aurila deformis, Lexoconcha cubensis, Quadracythere antillea, Jugoscocythereis cf. vicksburgensis, and

Post – middle Eocene Stratigraphy / 283

Perissocytheridea sp. The age is considered lower Miocene. The Husillo Formation lies unconformably over Eocene (and older) rocks; however, it is conformable over the Guanajay and Tinguaro formations. It is equivalent to the Jaruco Formation. This unit appears to have been deposited in relatively shallow water as indicated by the local biohermal and reefoidal blocks.

Jaruco Formation The Jaruco Formation, named by P. J. Bermudez in 1960 (Bermudez, 1961) consists of approximately 330 ft (±100 m) of cream to white argillaceous limestones. When fresh, the color is steel gray. They have a granular, medium to fine texture, and in general are massive to medium bedded. Sometimes, they are interbedded with the limestones of the Husillo Formation. The fauna consists of Globoquadrina altispira, Globoquadrina dehiscens, Globigerinoides trilobus, Catapsydrax sp., Orbulina(?) sp., Amphistegina sp., Globigerinatella insueta, Porticulasphaera transitoria, Globigeriroides bisphaericus, Globigeriroides subquadratus, Globigerina juvenillis, Globigerina rohri, Globorotalia barisanensis, Globorotalia mayeri, Tremalitus eopelagicus, Discoaster aster, Discoaster barbadiensis, Discoaster deflandrei, Discoaster woodringi, Braarudosphaera bigelowi, and Thoracosphaera spp. The age is considered lower Miocene. It is equivalent to the Husillo Formation and conformably overlies Tinguaro and Guanajay formations.

Cojimar Formation The Cojimar Formation (named by Palmer, 1934) consists of up to 1280 ft (390 m), but generally less than 260 ft (80 m) of calcareous and argillaceous marls and gray chalks. They weather to a dark yellowish cream to whitish yellow. The texture is commonly coarse and granular with fine sand present. These marls are interbedded with almost pure to argillaceous bioclastic limestones. Fossils are common. The fauna is very rich, including Orbulina universa, Orbulina saturalis, Globigerinoides inmaturus, Globigerinoides secculifer, Globigerinoides trilobus, Globigerinoides ruber, Globigerinoides quadrilobatus, Globoquadrina altispira, Globoquadrina dehiscens, Sphaeroidinella grimsdali, Sphaeroidinella dehiscens, Globorotalia praemenardii, Globorotalia archeomenardii, Globorotalia fohsi praefohsi, Globorotalia fohsi peripheroacuta, Globorotalia fohsi lobata, Globorotalia peripheroronda, Globorotalia obesa, Globigerinella aequilateralis, and Nummulites cojimarensis. On the basis of this fauna, the age has been determined to be middle Miocene and is a Globorotalia fohsi zone. The Cojimar Formation lies transitionally over the Jaruco and Husillo formations. It is a partial lateral equivalent to the Guines

Formation. These rocks were deposited in bathyal to neritic conditions in water less than 300 m (1000 ft) deep. In some areas, submarine channels have been observed.

Cangrejeras Formation The Cangrejeras Formation (named by Bro ¨ nnimann and Rigassi, 1963) consists of ±560 ft (± 200 m) of a well-bedded limestone sequence. The limestones are bioclastic and fossiliferous with many well-preserved megafossils. The following fossils have been reported: Nummulites cojimarensis, Heterostegina antillea, Amphistegina gibbosa, Amphistegina angulata, Globoquadrina altispira, Orbulina universa, and Archeolithothamnium sp., indicating a late middle Miocene age. These limestones were deposited in shallow water.

Gu¨ines Formation The Gu ¨ ines Formation consists of up to 790 ft (240 m) of massive biogenic limestones characterized by a strong karstic topography. Among these limestones are coral, bioclastic, recrystallized, dolomitized, and argillaceous limestones. It is richly fossiliferous, containing corals, echinoids, mollusks, fishes, bryozoa, foraminifera, sponges, and even manatees. Some of the identified foraminifera and other fossils are Archaias angulatus, Peneroplis proteus, Peneroplis planatus, Cyclorbiculina compress, Sorites marginalis, Gypsina globulus, Amphistegina angulata, Amphistegina rotundata, Amphistegina lessonii, Valvulammina affinis, Miogypsina antillea, miliolids, globigerinids, algae, Lithophyllum sp., Archeolithothamnium sp., Jania sp., and Amphiroa sp. This very widespread formation ranges from lower to middle Miocene possibly into the upper Miocene. It is a typical carbonate platform deposit.

Rosario Formation The Rosario Formation was named by Bro ¨ nnimann and Rigassi (1963) and redescribed by Albear Franquiz et al. (1985). It consists of 525 ft (160 m) of: 1) Green, gray, and red, sometimes mottled clays with oysters, abundant megafossils, and common clasts of Eocene limestones, porphyries, and tuffs. 2) Conglomerates with well-rounded limestone clasts and rare volcanics that contain abundant Teredo tubes. 3) Conglomeratic marls, with variable quantities of limestones and other clasts. The abundant fauna, which includes ostracods, indicates a middle Miocene age. This unit appears to

284 / Pardo

have been deposited in a shallow littoral basin with a strong land influence. It is, in part, equivalent to the Guines, Cojimar, and Cangrejeras formations. It lies unconformably over the Husillo Formation and other older Eocene and Cretaceous rock.

Drilling One deep well, EPEP Vegas-1, was drilled in southern Matanzas. It was spudded into a thin cover of Gu ¨ ines Formation and, in a few feet, reached the Cabaiguan* sequence.

WESTERN LAS VILLAS Pushcharovsky et al. (1988) show the Lower–Middle Eocene rocks of western Las Villas Province (called the Santo Domingo Basin) to be unconformably overlain by the sections below.

Jicotea Formation The Jicotea Formation consists of 920 ft (280 m) of marls, siltstones, sandstones, and conglomerates of upper Eocene age. Gulf divided this formation into three units called Perdomo* (oldest), Manacal*, and Mango* (youngest). These will be described as informal units as follows.

Perdomo* The Perdomo* consists of ±40 ft (±12 m) of conglomerates with a marly matrix and components consisting mainly of basic igneous and tuffs but also of some limestone fragments. The fossils consist of Discocyclina sp., Fabiania sp., Lepidocyclina pustulosa, Lithothamnium sp., and Tremastegina sp., indicating an upper Eocene age. This unit forms the basal conglomerate overlapping the Cifuentes*, Domingo*, and Cabaiguan* sequences.

Manacal* The Manacal* consists of an unknown thickness, but not more than a few hundred feet, of conglomerate with a marly matrix and components of Cifuentes* belt lithologies interbedded with conglomeratic limestones and unconsolidated chert conglomerates. The fauna is similar to that of the Perdomo* Formation and is therefore considered to be upper Eocene. The Manacal* Formation conformably overlies the Perdomo* Formation.

Mango* The Mango* consists of ±300 ft (±90 m) of yellow organic limestones interbedded with marls and con-

glomeratic limestones. The fossils consist of Archeolithothamnium sp., Dictyoconus sp., Fabiania sp., Lepidocyclina pustulosa, Lithothamnium sp., miliolids, Operculinoides sp., Asterocyclina sp., and Globorotalia sp. This unit is considered to be upper Eocene and overlies the Manacal* Formation.

Jia Formation The Jia Formation consists of 490 ft (150 m) of limestones, bioclastic limestones, and breccia conglomerates of lower Oligocene age transitionally above the Jicotea Formation.

Teguaro Formation The Teguaro Formation consists of 330 ft (100 m) of marls, shales, and siltstones.

Drilling Two deep wells have been drilled by EPEP in the western part of this area: Cochinos-1 and Mercedes-2. The thicknesses of the penetrated younger Tertiary section are as follows.

EPEP Cochinos-1 Drilled near the Bay of Pigs, 75 km (46 mi) south of Cardenas, it drilled through ±3115 ft (±950 m) of upper Eocene or younger limestones and then penetrated the Cretaceous Cabaiguan* sequence volcanics to a total depth of 11,490 ft (3503 m).

EPEP Mercedes-2 Spudded 65 km (40 mi) south-southeast of Cardenas, it drilled through ±3300 ft (±1000 m) of upper Eocene or younger limestones into the middle Eocene Cabaiguan* sequence. At ±8860 ft (±2700 m), it penetrated the Cretaceous volcanics to a total depth of 12,120 ft (4000 m).

SOUTH-CENTRAL BASIN This basin is an embayment, open to the south toward the Bay of Santa Maria, overlying a shallow depression over the postulated, deep-seated La Trocha fault. Pushcharovsky et al. (1988) describe the Tertiary section of this area as consisting of the upper Eocene Ferrer Formation overlain by the Oligocene Blanco and Vigia formations and La Gunatas and the Miocene Arroyo Palma Formation. Gulf did some detailed stratigraphic work in this area, breaking the section into several mappable units; therefore, Gulf’s nomenclature will be used in this re-

Post – middle Eocene Stratigraphy / 285

port. It is noteworthy that Gulf described the Llorente*, Zaza*, Suceso*, Cepeda*, Ferrer*, and Rollete* formations that appear to be subdivisions of the Ferrer Formation of Pushcharovsky et al. (1988). In the following, the Ferrer Formation will be described as an informal group.

Ferrer Group The Ferrer Group contains the following formations.

Llorente* Formation The Llorente* Formation consists of 400 ft (120 m) of thin-bedded, earthy white limestones and marls colored in part with yellow-brown iron stains. It contains a rich fauna with Hantkenina dumblei, Globorotalia cf. lehneri, Globorotalia spp., and Globigerina spp., suggesting a middle Eocene age. The Llorente Formation overlies unconformably the Siguaney*, Bijabo*, and Lana* formations of the Cabaiguan* sequence.

Zaza* Formation The Zaza* Formation consists of 500–1000 ft (150– 300 m) of massive, bluish white, very sticky, calcareous clay. The fauna is poor and contains radiolaria of Tertiary aspect, Globigerina sp., Amphistegina sp., Globorotalia centralis, Truncorotalia spp., Globigerina cf. apertura, Globigerina spp., and orbitoidal foraminifera, indicating an upper Eocene or slightly older age. The stratigraphic relationships are not clear, but it appears to overlie the Llorente* Formation and definitely is part of the Tertiary overlap.

Suceso* Formation The Suceso* Formation consists of 300–800 ft (90– 240 m) of blue, calcareous, sticky clay interbedded with blue clayey, micaceous sandstone and some conglomerate beds. The fauna is poor and undiagnostic; however, the unit definitely belongs to the Tertiary overlap and appears to overlie the Llorente* Formation. It is believed to be equivalent and similar to the Zaza* Formation.

Cepeda* Formation The Cepeda* Formation consists of 200–400 ft (60– 120 m) of orange yellow, fragmental, fossiliferous limestones and marls. The fauna consists of Fabiania sp., Asterocyclina spp., Discocyclina spp., Nummulites sp., Lepidocyclina sp. (of Lepidocyclina pustulosa group), Globorotalia spp., and Globigerina spp., indicating an upper Eocene age. The lower boundary is unknown.

Ferrer* Formation The Ferrer* Formation consists of 500 ft (150 m) of medium-bedded, loosely consolidated conglomerates, sandstones, and marls. The conglomerate is mostly made up of limestone, but some quartz and schist cobbles and boulders are also present. The fauna consists of Discocyclina spp., Asterocyclina sp., Fabiania sp., Lepidocyclina sp. (of Lepidocyclina pustulosa group), Amphistegina cubensis, and nondescript rotaloids. The age is upper Eocene, possibly extending into the lower Oligocene. The Ferrer* Formation conformably overlies the Cepeda* Formation.

Rollete* Formation The Rollete* Formation consists of more than 300 ft (90 m) of marls and conglomerates having soft limestone boulders in a marly matrix. Some conglomerates with igneous fragments are also present. The algal orbitoidal limestone fragments contain Lepidocyclina sp., Lepidocyclina pustulosa, Fabiania sp., Dictyoconus cookei, Reussella sp., Operculinoides sp., Discocyclina sp., Asterocyclina sp., and Globigerina sp., indicating an upper Eocene to lower Oligocene age. The Rollete* Formation appears to be equivalent to the Ferrer* and Cepeda* formations, but the stratigraphic relationships are not clear.

Perazo* Formation The Perazo* Formation consists of 200 ft (60 m) of white, soft limestone and orbitoid coquina. The fauna contains Rotalia mexicana var. mecatepecensis, Elphidium sp., Nonion sp., Gypsina globulus, Lepidocyclina spp., and bryozoans, indicating an Oligocene ( probably lower Oligocene) age.

Blanco* Formation The Blanco* Formation consists of 500 ft (150 m) of massive, dense, yellowish limestone, coralline in part, interbedded with marls containing large orbitoids. The fauna consists of Lepidocyclina spp. (with spatulate equatorial chambers), Amphistegina sp., Operculinoides spp., Planorbulina sp., bryozoans, small nondescript rotalids, and algae, indicating a lower to middle Oligocene age. This formation is in contact with the Perazo* Formation, but the nature of the contact is not clear.

Varga* Formation The Varga* Formation consists of more than 300 ft (90 m) of light-gray, sticky marl with small irregular limestone nodules. It contains a heterogeneous fauna suggesting an Oligocene or younger age. Contacts are unclear.

286 / Pardo

Jatibonico* Formation

Lara* Formation

The Jatibonico* Formation consists of 500 ft (150 m) of yellow marls and marly silts with large orbitoids, stringers of gray orbitoidal limestone, and coralline limestones. The fauna is poor, but suggests an Oligocene age.

The Lara* Formation consists of more than 200 ft (60 m) of marls, loosely consolidated sandstones, and pebble conglomerates with stringers of oyster shells. The fauna consists of an inconclusive assemblage of shallow-water Rotalia beccarii; however, it is similar to and belongs to the same outcrop pattern as the Ana* Formation.

Charcas* Formation The Charcas* Formation consists of less than 200 ft (60 m) of marls and sandy marls with stringers of thin orbitoidal beds. The lower part of this formation is an unconsolidated orbitoid coquina with the same lithology as the Perazo* Formation. The fauna indicates a lower to middle Oligocene age. This formation appears to overlie the Jatibonico* Formation, but the contacts are not clear.

Yayabo* Formation The Yayabo* Formation consists of 200–500 ft (60– 150 m) of hard silty marl with a pinkish cast, weathering to a cobbly surface. The fauna is inconclusive, but the formation is believed to belong to the Miocene. It is similar to the Lara* and Ana* formations.

Tomas* Formation

Drilling

The Tomas* Formation consists of an unknown thickness of marls, containing irregular limestone nodules, interbedded with fossiliferous yellow-cream, dense limestone with vuggy porosity in the outcrop. It is believed to be middle to upper Oligocene in age and appears to overlie the Charcas* Formation.

A large number of wells have been drilled in this depression, but little information is in the public domain. In general, however, the upper Eocene and younger Tertiary are thin (supporting the deep-seated origin of the strong gravity low).

Vigia* Formation

The Jucaro-1 was spudded by Trans-Cuba SA in 1954, 21 km (13 mi) south-southwest of Ciego de Avila. It drilled through the Neogene to ±820 ft (±250 m), where it encountered Cretaceous volcanics to a total depth of 3083 ft (940 m).

The Vigia* Formation (which has no relation to the Vigia Formation of Central Camaguey or the Vigia [Oriental] of eastern Cuba) consists of ±200 ft (60 m) of conglomerate with a sandy, marly matrix, and boulders up to 2 ft (0.6 m) in diameter of sandy, fragmental limestone similar in lithology to the Bijabo* Formation. This unit, which occurs in the Fomento-Taguasco area of central Cuba, contains abundant lower to middle Eocene faunas; however, from the field evidence, it appears to be Oligocene and mainly derived from the erosion of the Bijabo* Formation.

Trans-Cuba Jucaro-1

Trans-Cuba Sancti Spiritus-1 The Sancti Spiritus-1 was spudded by Trans-Cuba SA in 1955, 19 km (11 mi) southeast of Sancti Spiritus. It was reported in lower–middle Eocene at the total depth of 10,118 ft (3084 m). The depth to the base of the upper Eocene cover is unknown.

Playuela* Formation

Stanolina Tortuga Shoals-1

The Playuela* Formation consists of 300 ft (90 m) of white chalky marl, white sandy marl, and pebble conglomerates with a marly matrix. The fauna indicates an upper Eocene or younger age, but the field evidence indicates that it is very probably of Oligocene age. The Playuela* Formation is believed to overlie conformably the Vigia* Formation.

The Tortuga Shoals-1 was spudded by Cuba Stanolind Oil Co. in 1957, offshore 73 km (45 mi) south of Sancti Spiritus. It drilled through the Neogene and the upper Eocene to ±5050 ft (±1540 m), where it encountered middle Eocene to Upper Cretaceous rocks of the Cabaiguan* sequence to a total depth of 9703 ft (2957 m).

Ana* Formation The Ana* Formation consists of 500 ft (150 m) of marl, marl with limestone nodules, and sandy to conglomeratic marl. Some thin oyster beds exist. It contains a heterogeneous assemblage with reworked fauna indicating a Miocene age.

SOUTHEASTERN BASINS All of these basins are in the Oriente Province. The Guanacayabo-Nipe Basin (used to be called the Cauto Basin) extends across the island from the scarp southwest of the Jardines de la Reina archipelago east to the

Post – middle Eocene Stratigraphy / 287

Bay of Nipe. The Guantanamo Basin separates the Sierra del Purial from the Sierra Madre in southwestern Oriente, and the central syncline consists of a saddle connecting the two basins.

GUANACAYABO-NIPE BASIN According to drilling information, the Paleocene to middle Eocene Cauto Formation underlies this basin, and it appears to have its deepest part near the town of Bayamo; the upper Eocene and younger section is shown in Figure 151.

Monte Alto Formation The Monte Alto Formation (named by E. Nagy and G. Rado´cz in 1976 and published in Nagy et al., 1983) consists of a few tens of meters of detrital and bioclastic marls with a light- to dark-gray color. The upper part of the section is reddish brown, and the bedding is irregular and undefined. A few fossils have been found: Cidaridae, Ostreidae, and Crinoidea. In addition, some orbitoids are present. The age is generally considered upper Eocene.

Sevilla Formation The Sevilla Formation consists of up to 1909 ft (580 m) of hard, brownish-gray detrital limestones with many molds of mollusks, brachiopods, and tubular structures, as well as large lepidocyclinas. In addition, it contains fragments of tuffs, volcaniclastics, and Paleogene limestones. Toward the center of the Guacanayabo Basin, in the subsurface, it consists of an interbedding of limestones and calcareous shales with marls, siltstones, and reworked volcaniclastics. The characteristic fossils are Lepidocyclina sp., Amphistegina angulata, Lepidocyclina gigas, Lepidocyclina dilatata, Lepidocyclina chaperi, Miogypsina sp., and Globigerina ciperoensis. Reworked Eocene foraminifera also exist. The age is considered lower Miocene. It lies with marked unconformity over the Cobre Formation.

Limones Formation The Limones Formation consists of more than 1000 ft (300 m) of brownish-red, coarse-grained, porous calcarenites. They exhibit lenticular and cross-bedding and occasionally contain pebbles of older formations. The calcarenites are bioclastic. The fauna consists of Sorites marginalis, Sorites cf. magna, Archaias compressus, Nummulites dia, Amphistegina angulata, Amphistegina cf. gibbosa, and calcareous algae are abundant. In addition, there are reworked Eocene fossils. The age is considered middle Miocene.

FIGURE 151. Stratigraphic section, Guanacayabo-Nipe Basin.

Manzanillo Formation The Manzanillo Formation (named by Taber, 1934) consists of up to 3625 ft (800 m) of hard, massive, cavernous, white to brownish yellow, bioclastic limestones. These limestones are commonly fossiliferous and marly. They are interbedded with marls, shales, calcarenites, sandy marls, and cream, white, and gray medium-hard, calcareous shales. Some beds of pseudoconglomeratic limestones exist. In general, the bedding is irregular. The massive horizons are dominant. It has a rich mollusk fauna as well as echinoids and corals. The foraminiferal fauna is rich and dominated by shallow-water benthic forms such as Amphistegina,

288 / Pardo

Archais, Elphidium, and Quinqueloculina. The age is considered middle Miocene to Pliocene. It lies unconformably over the San Luis Formation as well as the Cobre and Farallon Grande Formation.

Cabo Cruz Formation The Cabo Cruz Formation (named by M. Kozary in 1956) consists of up to 660 ft (200 m) of hard, massive vugular white to yellowish brown or pink bioclastic limestones. Commonly, they are interbedded with red friable, fossiliferous sandy marls and fine- to mediumgrained yellow and red calcarenite. Some beds of wellcemented calcareous conglomerates with clasts of limestone up to 2 in. (5 cm) in diameter exist. This formation is thick bedded. It is richly fossiliferous, containing mollusks, echinoids, and shallow-water foraminifera where species of Amphistegina and Quinqueloculina are dominant. The age is considered middle to upper Miocene, possibly reaching the Pliocene. It lies unconformably over the Limones, the Cobre, and the Chafarina formations.

Pedernales Formation The Pedernales Formation consists of 500 ft (150 m) of unconsolidated polymictic conglomerates with a silty and sandy matrix. The color is mottled, predominantly brownish green to brownish blue. The clasts, which can reach 6 in. (15 cm) in diameter, are commonly well rounded, and they consist of basic and ultrabasic igneous rocks, tuffs, and Cretaceous and Paleogene limestones. Cross-bedding can be observed locally. The matrix contains Miogypsina cf. antillea, Amphistegina angulata, Lepidocyclina cf. gigas, Lithophyllus sp., Mesophyllum sp., Nummulites sp., and Crepitacella sp. The age is considered lower Miocene. It lies unconformably over the Vigia, Haticos, and Buenaventura formations, as well as above the rocks of the ultrabasic complex.

Bitirı´ Formation The Bitirı´ Formation (named by Iturralde-Vinent, 1972) consists of more than 1650 ft (500 m) of white, cream, yellow, and brown dense, brecciated, fine- to very fine-grained bioclastic limestones that exhibit an alternation of medium and thick beds and are interbedded with cream-colored marls containing limestone fragments. The fauna contains abundant pelagic foraminifera as well as abundant nannoplankton, indicating deposition in relatively deep and open water. The age is considered upper Oligocene– lower Miocene. It lies unconformably over the San Luis Formation.

Camaza´n Formation The Camaza´n Formation consists of 230 – 1440 ft (70– 440 m) of yellow, bioclastic limestones interbedded with well-bedded, yellowish marls with abundant lepidocyclinas. Beds of fine- to medium-grained, well-cemented calcarenites as well as pinkish yellow recrystallized sandy limestones exist. A few beds of greenish gray clays containing gypsum are observed. This formation contains a rich fauna of mollusks, echinoids, corals, benthic foraminifera, and nannoplankton. It was named by M. Kozary, and the age is considered upper Oligocene–lower Miocene. It lies conformably over, and also interfingers with, the Pedernales Formation and lies unconformably over older formations.

Jagu¨eyes Formation The Jagu ¨ eyes Formation consists of 130 –330 ft (40– 100 m) of interbedded marls, siltstones, calcareous gravels, medium- to coarse-grained calcarenites and coarse-grained bioclastic limestones. The section is medium to thin bedded and has a yellowish brown color. Some beds of green shale exist. It has a rich fauna of mollusks, corals, foraminifera, and nannoplankton. It is considered middle Miocene and lies unconformably over the Camaza´n, Bitirı´, and Vigı´a formations.

Yayal Formation The Yayal Formation was named by M. Kozary and consists of more than 660 ft (200 m) of hard, cream to white calcareous shales, cream to white, cavernous, bioclastic limestones, nodular grayish-green marls, and white to creamy green, cavernous, argillaceous dolomites. It contains mollusks and shallow-water benthic foraminifera. The age is considered middle Miocene. It lies unconformably over older rocks and is conformable over the Camaza´n and the Jagu ¨ eyes Formation.

Ju´caro Formation The Ju´caro Formation consists of tens of meters of brown, marly fossiliferous limestones alternating with white and cream, friable, sandy marls. Interbeds of gray to brown, medium-grained, moderately consolidated biocalcarenites with a silty matrix are observed. The bedding varies from thin to massive. It was named by M. Kozary and contains a very rich fauna of mollusks, echinoids, calcareous algae, foraminifera, and nannoplankton. It is considered upper Miocene and possibly Pliocene. It appears to lie conformably over the Jagu ¨ eyes Formation.

Post – middle Eocene Stratigraphy / 289

Bayamo Formation

San Luis Formation

The Bayamo Formation was named by P. Jakus and consists of up to 330 ft (100 m) of brown to mottled, sandy plastic clays, greenish gray to brown, fine- to medium-grained argillaceous sandstones with occasional gravels, grayish green and brown bentonitic clays, and whitish yellow and brown, fine- to mediumgrained friable sandstones. The formation is commonly medium to well bedded. The following foraminifera have been identified: Globgerininita cf. incrusta, Globigerina bulloides, and Globorotalia crassaformis. The age is considered upper Miocene–Pliocene. It lies conformably over the Yayal Formation and unconformably over the Charco Redondo and Camaza´n formations.

The San Luis Formation (named by Taber, 1934) consists of 2296 ft (700 m) of a great variety of clastic and carbonate rocks. Ninety percent of the formation consists of gray, brownish gray, and brown well-bedded, fine- to medium-grained sandstones. The bedding is thin to medium, and most of the fragments are derived from the Cobre Formation. The conglomerates are poorly sorted, polymictic, with a green to greenish gray or brown color, and consist mostly of volcanic fragments and various kinds of limestones. The clasts are derived from the Cobre, Charco Redondo, and Puerto Boniato formations. The siltstones are shaley and calcareous and sometimes sandy, and the color is gray when fresh and beige to brown when weathered. Occasional carbonized plant fragments exist. The limestones of the San Louis Formation are found on several levels. They are laminated, marly, of a white color, and are generally at the base of the formation. Sandy and bioclastic sandy limestones of cream color also exist. The fauna is very rich and is characterized by abundant planktonic foraminifera and nannoplankton, although a few benthic foraminifera such as Amphistegina lopeztrigoi, Eoconuloides wellsi, Dictyoconus americanus, Lepidocyclina antillea, and Lepidocyclina pustulosa are present. The age is considered upper– middle Eocene to upper Eocene. The San Louis Formation lies unconformably over the older La Farola, Cobre, Miranda, and Charco Redondo formations. It conformably overlies the Farallon Grande and Puerto Boniato formations.

Drilling Stanolind explored this basin for hydrocarbons in the late 1950s. Several wells, two of them offshore, were drilled without success. Unfortunately, the section penetrated by the wells is reported in the 1985 geologic map (Cuba, 1985a) in ages and not in stratigraphic terms.

Stanolind Rabihorcado-1 The Rabihorcado-1 was drilled through the Neogene and upper Eocene to ±3280 ft (±1000 m), where it penetrated the Cobre Formation to the total depth of 4266 ft (1205 m).

Stanolind Lavanderas-1 The Lavanderas-1 was drilled through the Neogene and the upper Eocene to ±3280 ft (±1000 m), where it penetrated the Cobre Formation to the total depth of 5535 ft (1688 m). Later, after the 1960 revolution, EPEP drilled a deep well on land near Bayamo, possibly near the center of the basin.

EPEP Granma-1 The Granma-1 was drilled through Neogene and Oligocene limestones and clastics to 5970 ft (±1820 m), where it penetrated the upper Eocene. At ±6690 ft (±2040 m), the well encountered the middle Eocene to ±8364 ft (±2550 m), where it penetrated the Cobre Formation to the total depth of 9898 ft (3017 m).

CENTRAL SYNCLINE This saddle separating the Guanacayabo-Nipe Basin from the Guantanamo Basin is underlain by the volcanics of the Cabaiguan* sequence to the north and the Cobre Formation to the south.

Camarones Formation The Camarones Formation consists of 1650 ft (500 m) of poorly sorted, poorly stratified, massive, green, greenish gray, and brown polymictic conglomerates and coarse-grained associated sandstones. The clasts consist of lavas and pyroclastic rocks, commonly silicified, and different kinds of limestones. The volcanics predominate, and 20% of the clasts are of acid composition. The conglomerates are commonly well cemented by calcium carbonate; the size of the components is about 4 in. (10 cm) in diameter, but can reach up to 24 in. (60 cm). They are rounded to subrounded. The fossils are characterized by the foraminifera Fabiana cubensis, Globigerina sp., Amphistegina lopeztrigoi, Nummulites trinitatensis, Nummulites cf. nassauensis, Heterostegina ocalana, Discocyclina marginata, Asterocyclina monticellensis, Pseudophragmina cf. cedarkeysensis, Pseudophragmina cf. psila, Eoconuloides wellsi, Lepidocyclina chaperi, Lepidocyclina macdonaldi, Lepidocyclina antillea, and Lepidocyclina cf. ariana

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and nannoplankton. The age is considered upper Eocene. Toward the north, this formation interfingers with the San Luis Formation; however, in most of the syncline, it overlies the San Luis Formation with an unconformity.

Sagua de Tanamo Formation The Sagua de Tanamo Formation (named by E. Nagy in 1976) consists of 395 ft (120 m) of white, whitish gray, thin- to medium-bedded marls interbedded with fine-grained, beige, hard limestones. The fauna consists of Discocyclina marginata, Discocyclina cubensis, Catapsydrax dissimilis, Lepidocyclina macdonaldi, Globorotalia centralis, Globorotalia densa, Globigerina senni, Globigerapsis kugleri, Hantkenina sp., and Nummulites floridensis. The age is considered upper Eocene. This formation lies comformably over the Puerto Boniato, Charco Redondo, and La Picota formations.

GUANTANAMO BASIN This epiorogenic basin separates the Purial massif metamorphics from the Cauto Formation outcrops of southwestern Oriente.

San Ignacio Formation The San Ignacio Formation (named by Boiteau and Campos, 1974) consists of 660–2300 ft (200–700 m) of a monomictic breccia in which components consist of greenschists and phyllite. In the upper part of the formation is a serpentine breccia. The fragments are commonly from 1 to 15 in. (2 to 40 cm), but some blocks can reach 13 ft (4 m) in diameter. Most of the blocks are angular, and the matrix consists of sand and silt of greenschist composition. This formation is barren of organisms, but in its upper part, a middle Eocene fauna has been found in some fragments. It is therefore considered late middle Eocene. This formation lies unconformably over the metamorphics and is equivalent to the Farallon Grande Formation.

Boquero´n Formation The Boquero´n Formation (named by Darton, 1926) consists of an unknown thickness of thick-bedded, poorly sorted conglomerates, with clasts from 2 to 8 in. (5 to 20 cm) in diameter. The matrix is made of brownish gray sandstone, and the clasts consist mostly of subangular, slightly metamorphosed sandstones. This unit appears to be related to the San Luis Formation and is considered upper Eocene, although no fossils have been found in the matrix.

Cilindro Formation The Cilindro Formation consists of up to 165 ft (50 m) of polymictic conglomerates with Lepidocyclina and corals. The clasts are subangular to rounded and poorly sorted, commonly near 2 in. (4 cm) in diameter, and consist of ultrabasics (up to 80%). It is interbedded with polymict sandstones and layers of lignite with impressions of plants. The fossils consist of Lepidocyclina cf. undosa, Lepidocyclina formosa, Lepidocyclina fragilis, Lepidocyclina fragilis cubensis, Lepidocyclina morganopsis, Lepidocyclina parvula, Lepidocyclina yurnagunensis, and nannoplankton. The age is considered lower Miocene. This formation unconformably overlies the San Luis, Miranda, and San Ignacio formations, as well as the Purial metamorphic complex.

Maquey Formation The Maquey Formation (named by Darton, 1926) consists of more than 1650 ft (500 m) of polymictic, argillaceous, friable, fine- to medium-grained sandstones and siltstones with calcareous cement. The bedding is well defined and thin to medium, and the colors are gray to brown. It has interbeds of yellow and brown sandy limestones and yellow-beige, mediumto coarse-grained bioclastic limestones. Thin beds of lignites with plant impressions are present. A rich fauna of mollusks, echinoids, ostracods, benthic foraminifera, and nannoplankton is present. Lepidocyclinas are abundant and varied. The age is considered upper Oligocene–lower Miocene. It lies conformably over the San Luis and the Cilindro formations. It is unconformable over the Miranda and San Ignacio formations.

Yateras Formation The Yateras Formation was named by M. Kozary and consists of some 130 ft (40 m) of hard porcellaneous, pinkish white, brown or cream, fossiliferous biogenic limestones. Fossils include the characteristic foraminifera Amphistegina angulata, Lepidocyclina cf. undosa, Lepidocyclina formosa, Lepidocyclina yurnagunensis, and Miogypsina sp. and nannoplankton, calcareous algae, and corals. The age is considered middle Miocene. This unit is conformable over the Maquey Formation and lies unconformably over the Cilindro and San Luis formations. It also lies unconformably over the Bucuey, Sagua de Tanamo, Castillo de los Indios, and San Ignacio formations.

SOUTHERN COAST Along the southern coast of Cuba are several stratigraphic units that were deposited on the north flank

Post – middle Eocene Stratigraphy / 291

FIGURE 152. Upper Eocene paleogeography. Modified from Iturralde-Vinent (1977).

of the Cayman trough. Because these are not relevant for the purpose of this publication, they will only be listed: (1) Capiro Formation (upper Eocene siltstones); (2) Cabacu´ Formation (upper Oligocene conglomerates); and (3) La Cruz Formation (upper Miocene siltstones, calcarenites, and limestones).

DISCUSSION OF THE POST–MIDDLE EOCENE STRATIGRAPHY OF CUBA In summary, during the late Eocene and later Tertiary, Cuba slowly emerged from the sea while depressions filled with sediment. In the late Eocene, very few areas of Cuba were above sea level; most of the orogenic process had occurred under deep water. This period of time also coincided with the strikeslip opening of the Cayman trough. This is a peculiar left-lateral feature where new crust was being generated in an east–west direction, with north– southtrending magnetic anomalies. The Cayman trough is bounded to the north by the Cayman Ridge, the westward continuation of the Sierra Madre Oriental. The history of Cuba from the late Eocene to the late Miocene (which has been very well summarized by Iturralde-Vinent, 1977) is shown in Figures 152–155. Late Eocene. During the late Eocene, Cuba consisted of an archipelago of relatively small islands. As shown

in Figure 152, only the Guaniguanico Mountains, parts of the coast in northern and central Cuba, the Escambray Mountains, the Isle of Pines, and the northern coastal area in southeastern Oriente were emergent. Consequently, no abundant source of terrigenous material exists, and most of the sediments were derived from extensive platform carbonates or were of pelagic origin. Middle – late Oligocene. During the middle to late Oligocene, much of the island was emergent. The Los Palacios Basin, the southern part of Habana and Matanzas provinces, the Central Depression, and the Guanacayabo-Nipe and Guantanamo basins in Oriente remained under water. As shown in Figure 153, most of the sediments remained carbonates from platforms in shallow waters and pelagic-argillaceous deposits in the deeper parts of the basins. Early Miocene. During the early Miocene, a slight transgression expanded (Figure 154) the Oligocene areas of sedimentation and terrigenous deposits accumulated in the Central Depression and eastern Cuba. Middle Miocene. The waters all over Cuba shallowed, and most of the island was under platform carbonate conditions, as shown in Figure 155. Coarser clastics were very restricted. Late Miocene. The entire island was emergent, with only part of the Zapata swamps and small areas in Oriente under water. Cuba has remained essentially

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FIGURE 153. Middle – upper Oligocene paleogeography. Modified from Iturralde-Vinent (1977).

the same ever since, with some subsidence along the coasts during the Pliocene and the Quaternary. It should be emphasized that the water temperatures during the late Eocene and Neogene were very

warm, which was combined with a lack of terrigenous detritus. Consequently, most of the deposits consist of bioclastic limestones, chalks, and other sediments with a high fossil content.

FIGURE 154. Lower Miocene paleogeography. Modified from Iturralde-Vinent (1977).

Post – middle Eocene Stratigraphy / 293

FIGURE 155. Middle Miocene paleogeography. Modified from Iturralde-Vinent (1977).

The position and depth of the post–middle Eocene basins are shown schematically in Figure 156. The 1989 Tectonic Map of Cuba (Pushcharovsky et al., 1989) also shows the depth to the ‘‘base of the Ceno-

zoic sedimentary cover’’ (unfortunately, their definition of the ‘‘base of the Cenozoic sedimentary cover’’ is not clear; at any rate the map probably represents the basins fairly well).

FIGURE 156. Cuba post – middle Eocene basin thickness. Modified from Iturralde-Vinent (1977).

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Pardo, G., 2009, Geophysical characteristics, in G. Pardo, The geology of Cuba: AAPG Studies in Geology Series, no. 58, p. 295 – 309.

Geophysical Characteristics GRAVITY

lished in Dengo and Case (1990), is unfortunately at a 1:5,000,000 scale (contoured at 25 milligals) and, therefore, too generalized to be related to details of the Cuban geology. This map is the base for the Caribbean part of the 1987 Gravity Anomaly Map of North America (Tanner et al., 1987; scale 1:5,000,000). This map is contoured at 10 milligals intervals. It is, however, very useful from a broad regional standpoint. It should be pointed out that the given gravity values are Bouguer on land and Free Air at sea. It is not known where the boundary between the two is in shallow waters, although it is presumed that in these areas, Bouguer and Free Air values are close to each other.

History The earliest gravity survey in Cuba was conducted mostly in Matanzas and Las Villas provinces in 1932– 1935 by the U.S. Coast and Geodetic Survey. Between 1935 and 1958, international oil companies conducted surveys in several local areas. Among these were the southern Pinar del Rio and the northern Isle of Pines; the coastal areas of northern Habana, Matanzas, Las Villas, and Camaguey; parts of southern Camaguey and southwestern Las Villas; and western Oriente. These surveys were of high precision but were not connected to each other. In 1958, the U.S. Government (Coast and Geodetic Survey) began to establish gravity base stations in Cuba tied to Panama, which is part of the global gravity network with its origin in Potsdam. Four base stations were established: San Julian, Habana, Santa Clara, and Siguanea. After 1959, the Cuban Institute of Geography and Geodesy continued this work, and by 1962, the following bases had been established; 7 first class, 13 second class, and 2500 fill-in. In 1962, in cooperation with the Institute of Earth Physics from the former Soviet Union’s Academy of Science, the Cuban Institute of Geography and Geodesy established a new base network of 62 stations. From then on, all the surveys were tied to the base station network. As of 1971, some 60% of the island had been surveyed at scales of 1:50,000 and 1:100,000. In 1971, Ipatenko and Sashina published a 1:3,000,000 gravity map of Cuba. The most recently published regional gravity maps were done as an insert in the 1985 Geologic Map (Cuba, 1985a; scale 1:500,000 and contoured at 10-milligal intervals), based on the published work of Ipatenko and Sashina, and in the 1988 New Atlas of the Republic of Cuba (Sanchez Herrero, 1988; scale 1:1,000,000). The gravity map compiled by Westbrook and pub-

Description of the Gravity Anomalies In general, the gravity field over the island of Cuba is between 30 and +100 milligals. This is in the general range of continental values. In eastern Cuba, in the Sierra del Purial area, the values climb to more than 160 milligals (see Figure 157). The most obvious features of the gravity field are: 1) A marked gravity low exists, from +70 to +10 milligals southward across the Pinar Fault. This low reflects the presence of the thick, lowdensity, Tertiary clastics of the San Diego de los Ban ˜ os Basin. 2) A gravity minimum with values ranging from 0 to 30 milligals extends from Cardenas Bay through the town of Camaguey as far as the town of Gibara; this coincides with the northern contact between the carbonates to the north and the basic igneous-volcanic province to the south. It reflects a major fault. Note that the carbonates outcropping over the gravity low are commonly high density, without much associated lowdensity material, and therefore, the surface expression of the fault alone cannot explain the

Copyright n2009 by The American Association of Petroleum Geologists. DOI:10.1306/13141063St583328

295

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FIGURE 157. Cuba gravity anomaly map (mGal = milligal).

3)

4)

5)

6)

7)

gravity minimum; deeper crustal material must be involved. An east-northeast-trending gravity low, with values reaching 30 milligals, in western Camaguey coincides with the Central Depression or the Trocha fault zone. The reason for this anomaly is not entirely clear; although a shallow basin exists, the density contrast of the near-surface sediments is not believed large enough to produce an anomaly of such magnitude, therefore it must originate at basement level. The outcrops of metasediments of the Isle of Pines and the Escambray Massif have relatively low values in the order of +25 milligals. The gravity appears to indicate a connection between the two. Everywhere in Cuba, the outcropping volcanics show positive values of up to +70 milligals. They also show characteristic high-frequency anomalies. The large positive anomaly in Oriente, reaching more than +150 milligals, coincides with extensive ultrabasic outcrops. As will be seen in the next section, it coincides with a shallow (16-km; 10-mi) Moho discontinuity. The generally high gravity values along the south coast of Oriente are over outcrops of lower–middle Eocene volcanics of the Cobre Group, extending westward along the Cayman Ridge, and might

reflect a high crustal block adjacent to the Cayman trough. The Cayman trough shows a prominent gravity low with values less than 150 milligals. 8) As will be seen later, the Free Air gravity low that reaches 60 milligals and extends from south of the Isle of Pines to the south of the Jardines de la Reina Cays might be in part the expression of a presently inactive subduction zone. It might also be an expression of the change in submarine topography. 9) As will also be seen later, the Free Air gravity low that reaches 80 milligals and extends from north of Pinar del Rio to Cardenas Bay could be the expression of an important thrust zone, bringing the island of Cuba over the southern Gulf of Mexico. It is the continuation of the thrust front mentioned above, although it could be an expression of the change in submarine topography. 10) There are several long, linear gravity lows and highs, paralleling the coast between Cardenas Bay and Cayo Coco. They must reflect structures (possibly fault blocks) or sediment changes within the coastal area. The significance of the Cuban gravitational features will be discussed in more detail in Chapter 6 of this publication.

Geophysical Characteristics / 297

MAGNETICS History Reasons exist to believe that the earliest aeromagnetic surveys on the island of Cuba were run for Gulf Oil in 1948. Later, in 1959, an aeromagnetic survey of the north shore of the island was flown for Gulf as part of a larger regional survey of southern Florida and the Bahamas. Aeroservice Corp. ran these surveys. During the years 1956 –1957 and 1961– 1962, Aeroservice Corp. ran three surveys over western, central, and eastern Cuba. These surveys had arbitrary origins for the values of the magnetic field. From these data, the Cuban Institute of Mineral Resources prepared three maps: Pinar del Rio at 1:50,000 and with 10-gamma contour intervals; northern Habana and Matanzas at 1:40,000, also at 10-gamma intervals; and the rest of the island at 1:192,000 with contour intervals of 25 gammas (5 gammas in magnetically quiet areas). Based on these maps, a 1:250,000 map was compiled, with contours at 25-gamma intervals. Unfortunately, the problem of arbitrary origins remained. In 1964, Soloviev et al. published a description of the method used to prepare a regional, corrected magnetic map at 1:500,000 with 100-gamma contour intervals in disturbed areas, and 50 gammas in quiet ones. (The Cuban and Russian publications describe the magnetic field in milliOersted [mOe], which is a magnetic field strength unit [1 Oe = 79.577 Ampere/ meter]. The North American maps are in nannotesla [nT] or gamma [G], which are magnetic flux density units [1 nT = 1 G, and 1 T = 1 volt second/meter2]. The Cuban and Russian maps show 1 mOe = 10 gammas, which is an error because 1 mOe = 100 G although the two units are not exactly comparable.) In the same article, the authors published a 1:3,000,000 residual magnetic anomaly map of the entire island with 1-mOe (100-gamma) contour interval. Later, a magnetic anomalies map, based on Soloviev et al. publications, was printed as an insert to the 1985 Geologic Map (Cuba, 1985a; scale, 1:2,500,000). The most recently published magnetic map is in the 1988 New Atlas of the Republic of Cuba (Sanchez Herrero, 1988; scale, 1:1,000,000). Like the gravity map, the scale of the magnetic map compiled by Hall and Westbrook and published with the GSA DENAG Volume of the Caribbean Region (Dengo and Case, 1990) is too small to permit comparison with geologic features. In addition, the large number of high-frequency anomalies makes the map very hard to read. This map is the base for the Caribbean part of the Magnetic Anomaly Map of North America (Tanner et al., 1987) at 1:5,000,000, where the data

have been smoothed, making the map more interpretable from a regional standpoint. This map is contoured at 100-gamma (100-nT) intervals.

Description of the Magnetic Anomalies The following features characterize the Cuban magnetic anomaly map (see Figure 158). 1) The north coastal region, from Cardenas Bay to Gibara, shows a featureless magnetic field indicating a deep and/or featureless basement. Depth estimates on Gulf’s surveys indicate as much as 30,000 ft (9100 m) to the basement. 2) The northwestern coastal area of Pinar del Rio also shows a featureless magnetic field, probably indicating a deep basement. 3) A regional magnetic low, extending from Matanzas to Oriente near the north coast of the island, and coinciding with the gravity minimum described under feature 2 in the previous section of this chapter on gravity. It reaches a minimum of less than 200 gammas ( 200 nT). 4) In Pinar del Rio, there is also a median magnetic low parallel and immediately south of the Pinar fault. Like the corresponding gravity low, it appears related to the Tertiary fill of the San Diego de los Ban ˜os Basin. 5) South of the province of Matanzas and extending along the southern half of Cuba all the way to Nipe Bay, the magnetic field is characterized by a very large number of high-frequency, mostly positive anomalies. These reflect the presence of the shallow igneous bodies of the basic igneousvolcanic province. They appear to continue westward under the Gulf of Batabano, north of the Isle of Pines, and terminate abruptly in eastern Pinar del Rio (Pinar fault). 6) The above trend of anomalies is interrupted by an east-northeast-trending magnetic low that coincides with the Central Depression gravity minimum (described under feature 3 of the previous section of this chapter on gravity). This supports the possibility that basement is responsible for both the gravity and the magnetic anomalies. 7) To the southwest, coinciding with the Isle of Pines and the Escambray metamorphic massifs are two gravity minimums, the one in the Escambray being less than 200 gammas. A suggestion that these two massifs might be connected has been made. The third metamorphic massif in Asuncion, at the southeasternmost end of the Sierra del Purial, also has a featureless magnetic expression.

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FIGURE 158. Cuba magnetic anomaly map.

8) Habana, Matanzas, and southeastern Pinar del Rio are characterized by a relatively featureless magnetic expression. In places there are sharp anomalies, suggesting isolated igneous bodies within the sedimentary section over a deep basement. 9) Along the southern coast of Oriente, in the southern Sierra Maestra, is a sharp, east–west-trending, high-low feature that is possibly associated with the Cayman trough. A similar feature can be seen 200 km (124 mi) to the west along the south flank of the Cayman Ridge. The number of correlations between low-frequency gravity and magnetic anomalies suggests that a deepseated basement determines both. However, a large number of cases exist where strong, high-frequency, magnetic anomalies are superimposed on gravity minimums, revealing the near-surface presence of igneous material over a deep basement.

CRUSTAL MEASUREMENTS From 1972–1975, the All-Union Scientific Research Institute of Geophysics conducted a project aimed at determining the deep crustal structure of Cuba. The method used refraction shooting along long pro-

files parallel and perpendicular to the regional strike, as well as the conversion of transmitted earthquake waves. Between 1978 and 1982, B. E. Scherbakova, V. G. Bovenko, and H. Hernandez, among others, published the results of this project. Figure 159 shows the location of the refraction sections as well as the refraction shot lines. Figure 160 shows the location of the crustal columns as inferred by the earthquake wave conversion method. It should be noted that because of the small scale of the published information, the location of the sections and shot lines is approximate. Figure 161 shows the crustal thicknesses and the seismic velocity columns based on the refraction shooting; it also shows profiles I, IV, and VIII, which were used for gravity modeling and seismic analysis. Figure 162 is a map of crustal thickness (depth to the Moho discontinuity) after Scherbakova et al. (1978a, b) and Bovenko et al. (1981, 1982). The results of these studies are difficult to evaluate; in their 1977 and 1988 articles, Scherbakova et al., conclude that the entire island of Cuba is underlain by a sedimentary-volcanogenic cover with thickness ranging from 2.0 to 12.5 km (1.2 to 7.7 mi), a granitic layer with thickness from 5.5 to 12.0 km (3.4 to 7.4 mi), and a basaltic layer 6.0–21.5 km (3.7–13.3 mi) thick.

Geophysical Characteristics / 299

FIGURE 159. Crustal measurement locations.

FIGURE 160. Crustal measurement locations.

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FIGURE 161. Refraction velocity sections. The following velocities were used as criteria for differentiating the layers: Granitic layer Basaltic layer Upper mantle

Vp = 6.2 km/s Vp = 7.0 km/s Vp = 8.1 km/s

Vp/Vs = 1.80 Vp/Vs = 1.76 Vp/Vs = 1.80

Furthermore, they state that the island is broken into blocks by deep-seated, vertical to near-vertical faults, and that each block has its own layer thickness distribution and somewhat different physical characteristics. This high-angle, vertically faulted, layer cake, basement tectonic model is certainly not com-

FIGURE 162. Crustal thickness.

patible with the surface observations. It is consistent with Soviet-era interpretations elsewhere in the world, so it may be a consequence of standard interpretation methods by Soviet-era or Soviet-era-trained researchers. Of great significance, however, is the identification of a discontinuity dipping 45–708 to the south that extends from south of La Habana to the Bay of Nipe. The trace of this discontinuity, which is referred to as a suture, is parallel to the regional structural trend and occurs generally south of the main body of ultrabasics and north of the Upper Cretaceous intrusive granodiorites. It seems to follow the axis of the Cretaceous

Geophysical Characteristics / 301

volcanic synclinorium. It is not clear whether this suture continues west-northwest toward the Gulf of Mexico or changes course southwestward and parallels the Pinar fault in Pinar del Rio. Perhaps it branches. At any rate, this suture is reflected in both the gravity and magnetic maps. Although Scherbakova et al. (1978a, b) point out that the Moho is commonly difficult to identify, Figure 163 shows crustal thinning (less than 24 km [15 mi] from a more than 28-km [17-mi] general background) associated with the suture as well as a prominent Moho high (12–16 km [7.4–10 mi] in depth) in western and southern Oriente. Perhaps there, the suture is not as closed as it is in central and western Cuba. In a more recent article by Bush and Scherbakova (1986), profiles I, IV, and VIII (from the previously mentioned refraction study) were used to do gravity modeling across the island. In this article, the authors appear to have relied more on gravity and surface geology than on seismic refraction data to build their model. The suture concept is maintained, but these profiles, shown in Figure 163, show that the model has been considerably changed: 1) The Moho is not shown but referred to as the top of the asthenosphere, present in the 30–40-km (18–25-mi) range only south of the suture. 2) What was previously the crust has been divided in three layers, with the upper two only being named upper and lower crust and the lower remaining unnamed. 3) What was formerly named the Moho north of the suture, and in Profile 1, in Pinar Del Rio, is now the new base of the crust, making the crust thickness north of the suture considerably thicker than to the south. In profile I, in Pinar del Rio, what was the Moho is now the new base of the crust. 4) The suture zone has become a slab ±8 km (±5 mi) thick with its own physical properties. 5) The previously reported internal velocity variations of the zones are ignored. 6) Finally, and most serious of all, profile I depicts the Pinar fault as a feature similar to the ophiolite front in central Cuba, which is not supported by field observations. In profile IV, the outcropping ophiolites are shown north of the gravity minimum, when in reality, they either coincide with it (or are south of it), and in profile VIII, the gravity minimum does not appear to be properly located in relation to the model. It should be noted that the strike of profile VIII is at an angle of 40 – 508 to the trend of the gravity minimum and the re-

gional strike, which would have a profound effect in the computations if the model were not three-dimensional. According to this later article, some of the original conclusions of B. E. Scherbakova must have been changed. The simple, two-dimensional type of gravity modeling (it appears to be a modification of M. Talwani’s) that was used certainly does not provide any new data but simply another interpretation of the same data. A familiar problem with this kind of modeling is that there is no unique answer. Despite the above uncertainties, some interesting interpretations have been made on the nature and structure of the Cuban crust. Pushcharovsky et al. (1988) present a classification of the types of crust and their location. Pushcharovsky et al. (1989) show the same scheme in a 1:2,500,000 insert in the 1989 Tectonic Map of Cuba. According to these authors, the crust consists of the following: 1) The continental North American crust in north central Cuba, 22–30 km (13–18 mi) thick, consisting of three layers; a 5–7-km (3.1–4.3-mi)-thick sedimentary cover over a granitic-metamorphic and a basaltic layer of equal thicknesses. The southern part of this crust is overlain by the sedimentary and ophiolite thrusts. 2) In Pinar del Rio, the crust consists of components from both the North and South American continents. It is somewhat thicker, 24 – 30 km (15 – 18 mi), and the granitic-metamorphic layer is 10 km (6 mi) thick versus 15 km (9 mi) for the basaltic layer, and the southern boundary is along the Pinar fault. 3) Separated from the continental crust by the geosuture is a transitional crust (of possible late Cretaceous age), 28 –32 km (17 –20 mi) thick with a basalt layer up to 20 km (12 mi) in thickness, whereas the granitic-metamorphic layer is only 3.5 – 8 km (2.1 – 5 mi) thick and discontinuous. This crust can be divided into two segments: the one under the basic igneous-volcanic province to the north, containing granitoids, and the Escambray – Isla de Pinos to the south, which is considered to contain South American crustal components. 4) In central Oriente, there is a relatively shallow dome of suboceanic ultramafic material, with a greatly reduced crust, 14–18 km (8–11 mi) thick, coinciding with the already mentioned strong positive gravity anomaly.

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FIGURE 163. Crustal profiles I, IV, and VIII.

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5) In southern Oriente and along the Cayman Ridge is another belt of transitional crust of Paleogene age with well-defined granitic-metamorphic and basaltic layers. 6) The Yucatan Basin and the southern Gulf of Mexico are underlain by a suboceanic crust with thicknesses ranging from 8 to 20 km (5 to 12 mi). 7) The Cayman trough is underlain by oceanic crust. The above blocks show many offsets by eastnortheast-trending left-lateral transcurrent faults. Here again, it is difficult to evaluate the meaning of these conclusions. They are obviously not entirely derived from geophysical studies; the hypothesis of the South American origin of some of the crustal blocks, although possible, must be based on some geological considerations because it cannot be derived from the geophysical data alone. What is the relationship between the extensive ophiolites and basic volcanics of the basic igneous-volcanic province and the intermediate crust underlying them? Are they part of that crust (velocity inversions have been reported)? Are the metamorphics of the Isla de la Juventud and Escambray massif considered part of the graniticmetamorphic layer of the South American crust, or are they overlying that layer (the problem of reverse metamorphism)? In conclusion, it can be said that the problem involving the geometry and nature of the crust underneath the island of Cuba is still not resolved. The most significant observations are as follows: 1) The presence of a crustal suture (disturbed zone) along the axis of the island and extending from Habana to the Bay of Nipe (the crustal thinning northward across the suture might be the result of Moho miscorrelations) 2) The deep-seated nature of the Pinar fault 3) The presence of thin crust–shallow mantle in eastern and possibly southern Oriente 4) The general intermediate (noncontinental and nonoceanic) nature and thickness of the crust 5) The general internal complexity of the crust suggesting its involvement in compressional and transcurrent tectonics

REFLECTION SEISMOGRAPHY Seismic reflection surveys were conducted in several places for many years. Before 1960, the results were disappointing as far as resolving pre-Tertiary structures.

Since the revolution, seismic parties (Soviet, Compagnie Generale de Geophysique [CGG], and others) have been continuously active. The results have not been released. Echevarria-Rodriguez et al. (1991) stated that more than 50,000 km (31,000 mi) of seismic lines (most of them marine) were analyzed. They published two profiles from the offshore north coast, a north– south 18-km (11-mi) profile in 4000 ft (1200 m) of water north of Cardenas Bay and a northeast–southwest 22-km (13-mi) profile in 1500 ft (450 m) of water some 20 km (12 mi) north of Cayo Coco. These profiles appear to be of recent vintage and must be some of the best available (the article is in the Journal of Petroleum Geology and is of a promotional nature). They do show structures at what the authors call the Upper Cretaceous level, but unfortunately, nothing can be resolved below that point. The reflections identified as the Jurassic are very probably multiples. In view that nothing is known about the processing, it is not known whether anything more can be obtained from this type of data because the pre – lower Eocene structures can be extremely complex. However, the authors claim that several north coast fields, including Varadero and Boca de Jaruco, were discovered through seismic surveys. Differing opinions exist that they were found through random drilling (70 deep wells in the area as of 1974). Hernandez Perez and Blickwede (2000) published five short profiles regarding the deep water north of Cuba. The article, in the Oil & Gas Journal, is also of a promotional nature, and the prints are of poor quality. The authors present, as line drawings, interpretations of profiles A and B (see Figure 164). Profile A, north of the Havana-Matanzas anticline, shows structurally disturbed, pre-Tertiary sediments over its entire length of approximately 31 km (19 mi), but the thrust front appears to be some 12 km (7 mi) south of the north end of the profile. Assuming an average velocity of 15,000 ft/s (4500 m/s), it also shows a possible de´collement surface at ±31,250 ft (±9500 m) below sea level. Profile B, north of western Pinar del Rio (Martin Mesa?), shows the thrust front approximately 10 km (6 mi) north of the southern end of the profile. Assuming the same average sediment velocity, at least ±32,725 ft (±9974 m) exist to a possible de´collement, and north of it, ±24,750 ft (±7543 m) of undisturbed sediments below 6750 ft (2057 m) of water exist. These numbers suggest basement or salt at ±32,000 ft (±9753 m) below sea level. The Institute for Geophysics of the University of Texas ran an extensive multichannel survey in the Yucatan Basin between 1975 and 1980. Although this survey does not cover Cuban territory, it has

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FIGURE 164. Cuba seismic profiles A and B. See Figure 168 for location. Author’s interpretation from sections published by Hernandez Perez and Blickwede (2000).

bearing on the geology and geologic development of the island. The data have been reported by Holcombe et al. (1990) and Rosencrantz (1990), and it shows a trench and northeast-dipping subduction under eastern and possibly central Cuba, southwest of and paralleling the Jardines de la Reina Cays (Figure 165).

TEMPERATURE AND HEAT FLOW Cermak et al. (1984, 1991) published two articles on temperature and heat flow in several localities throughout the island. The measurements were made in 36 boreholes (Figure 166) that had not been disturbed for periods ranging from several months to several years and were, therefore, in thermal equilibrium with

the surrounding rocks. The depth at which the measurements were taken ranges from 295 to 4887 ft (90 to 1490 m). Figure 167 shows a table summarizing the results of the study. In general, Cuba is characterized by a low geothermal gradient and a low to very low heat flow. It is difficult to draw conclusions from these data except that the mean of 45 mW/m2 (milliWatt per square meter) is close to that of the Gulf of Mexico (<40 mW/ m2), the Florida-Bahamas Platform (±50 mW/m2), and the Yucatan Basin (±58 mW/m2). It is in contrast with the high geothermal activity of the Caribbean (±88 mW m 2 in the Cayman trench). Interestingly, the highest heat-flow values were obtained in the Central Depression (63 mW/m2) and Jatibonico (50 mW/m2), whereas, unexpectedly, the lowest heat-flow values were obtained in southeastern Oriente at Puriales,

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FIGURE 165. Yucatan Basin seismic profile C: Camaguey trench. See Figure 168 for location. Modified from Holcombe et al., 1990.

(25 mW/m2), which is supposedly underlain by the thinnest crust over a mantle dome. It should be noted that rock samples for thermal conductivity measurements were not available from all the wells, in which case samples were taken from nearby outcrops, therefore introducing a possible source of error in heat-flow calculations. The heat flow and geothermal gradient of northern Cuba under the carbonates has probably been the same or similar to the present heat flow for a long period of time ( perhaps since the Jurassic), whereas the heat flow of the southern volcanic, igneous, and metamorphic provinces must be of much more recent origin, possibly since the late Eocene. These conditions have certainly had an important influence on the kerogen maturation. Another interesting feature of the Cuban geothermal gradient is an inversion that occurs between 330 and 650 ft (100 and 200 m). At that depth, the temperature can be on the order of 5.58F (3.08K) lower

than the surface temperature. The undisturbed geothermal gradient is commonly present below 650 – 820 ft (200 – 250 m). This anomaly is independent of the surrounding rocks or the depth of the water table and is present in most surveyed locations; it is believed to be the result of the global warming that followed the last glaciation.

PALEOMAGNETISM Several paleomagnetic studies have been made in Cuba. Renne et al. (1991) discusses southern Las Villas Province on the south flank of the Seibabo syncline. They report the results of the study of 42 specimens in five out of seven localities. Three of the selected localities are in Aptian–Albian volcaniclastics and two are in overlying Cenomanian micritic limestones. The data from the remaining two are unusable. Unfortunately, all the samples have a strong magnetic

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FIGURE 166. Heat-flow measurements.

overprint of unknown origin that could not be removed. However, they do show between 40 and 508 of counterclockwise rotation. Whether this is indicative of rotation of the entire volcanic belt or rotation of individual blocks caused by the eastward displacement of southern Cuba in relation to North America is open to question. Although a northward displacement is inferred, it is not supported by the data. Chauvin et al. (1994, p. 1691) conclude that, ‘‘the entire Cretaceous succession of the Zaza terrane was remagnetized in the Campanian. The measured latitude is lower by 158 ± 68 with respect to the North American APWP indicating ca. 1600 ± 600 km northward displacement of the Zaza terrane since the Campanian. Also discordant is the measured declination implying 378 ± 118 counterclockwise rotation of the Zaza terrane.’’ Bazhenov et al. (1996, p. 65) reached the following preliminary conclusions: ‘‘In contrast, well-defined characteristic components were isolated from basalts of the Aptian–Albian Encrucijada and the Late Cretaceous Orozco formations from the Bahia Honda zone in the north of western Cuba; the remanence in the Encrucijada Formation is shown to predate deformation. Mean inclinations in both formations match those in Cretaceous volcanics from central Cuba, and all the results show lower latitudes than expected from the reference data for the North American Plate, thus implying that volcanic domains of Cuba were displaced northward by about 1000 km prior to the middle Eocene. Cretaceous declinations in western

and central Cuba differ by about the same amount as the major structural trends of these two areas suggesting oroclinal bending of Cuba. At the same time, both areas are rotated counterclockwise with respect to North America, thus implying movements on a broader scale.’’ Alva-Valdivia et al. (2001, p. 716) state that, ‘‘The mean palaeodirection obtained in present study is not significantly different from the expected Jurassic– Cretaceous palaeodirections estimated from the North American apparent polar wander path, at least from 140 to 60 Ma. This suggests that no major latitudinal displacements and rotation have affected the Guaniguanico Cordillera since the Jurassic period.’’ Fundora Granda et al. (2003) show the eastern Cuba volcanics migrating from 108S in the Lower Cretaceous to 228N in the present and, surprisingly, also making a 1808 clockwise rotation. It therefore seems that, so far, the general consensus is that the Guaniguanico sedimentary belts have not moved much in relation to North America, whereas the basic igneous-volcanic terranes have moved more than 1000 km (600 mi) in a north-northeast direction and show a counterclockwise rotation. Much work along these lines remains to be done.

AGE DATING Iturralde-Vinent et al. (1996) present the results of a large number of K-Ar age determinations. They

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FIGURE 167. Heat-flow measurements.

are grouped according to broad areal distribution and rock types (igneous, volcanics, metamorphics, Escambray, Sierra Maestra, etc.), but unfortunately, there is no precise location or stratigraphic identification. Some of the results can be summarized as follows: 1) Cifuentes belt basement (Socorro complex): 139– 150 Ma, with marble dated at ±900 Ma 2) Escambray metamorphics: 55 – 85 Ma, with median at 66 Ma 3) Isla de la Juventud metamorphics: 49–78 Ma, with median at 66 Ma

4) Cretaceous volcanics: 53 – 100 Ma, with median at 77 Ma 5) Cretaceous plutons (Sancti Spiritu granodiorite): 50 –99 Ma, with median at 78 Ma 6) Paleogene volcanics (El Cobre): 39 –58 Ma, with median at 47 Ma 7) Mafics of northern ophiolites (Domingo*): 52 – 160 Ma, with median at 105 Ma 8) Mabujina complex: 44 –89 Ma, with median at 81 Ma 9) Metamorphic inclusions in the ophiolites: 91 – 196 Ma, with median at 111 Ma

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FIGURE 168. Summary of geophysical data. See Figure 164 for seismic profiles A and B; see Figure 165 for seismic profile C.

Without further stratigraphic details and more precise locations, it is impossible to attempt to explain the broad scattering of age determinations. However, the data support the theory that the Paleocene metamorphism of the sedimentary section (Escambray and Isla de la Juventud) is younger than the Campanian volcanic arc and could be related, at least partially, to the obduction process.

GEOPHYSICAL DATA DISCUSSION The geophysical information available to the author indicates several relationships concerning the general structure of Cuba (see Figure 168). 1) A definite continuity exists between the basic igneous-volcanic province of central Cuba and northern Oriente and the Bahia Honda belt of western Cuba. Assuming that the basic igneousvolcanic province had roots between the north-

ern carbonate belts and the Escambray metamorphics, it must also have had roots north of the Guaniguanico Mountains. However, if it originated south of Guaniguanico and was thrusted northward, then it must have originated south of Escambray and been also thrusted northward over the metamorphics. 2) A regional gravity and magnetic low anomaly extending from Cardenas Bay to Holguin exists. This anomaly coincides approximately with the boundary between the carbonate outcrops to the north and the basic igneous rocks to the south. Its south flank also coincides with what has been interpreted as a crustal discontinuity based on refraction seismography. It has been called a suture by several authors. 3) A few reflection profiles, gravity anomalies, as well as some drilling information suggest that the Cuban structural front extends all along the north coast of the island some tens of kilometers offshore.

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4) A seismic reflection profile south of the Jardines de la Reina archipelago shows a buried trench over a possible inactive northeast-dipping subduction. A high-low gravity anomaly, extending past the Isla de la Juventud, suggests that this trench might mark the boundary between Cuba and the Yucatan Basin. 5) The Central Depression is characterized by marked gravity and magnetic lows. They are the basis for the Trocha fault. 6) The Isla de la Juventud and the Escambray massif are also characterized by gravity and magnetic anomaly lows. There seem to be an east – west connection between the two. 7) South of the main island of Cuba and north of the Isla de la Juventud is a pronounced east–west positive gravity and magnetic anomaly extending from La Coloma in southeastern Pinar del Rio to Cienfuegos. The cause for this anomaly is unknown, but together with the refraction seismography, it suggests either a thinner crust or a

body of basic igneous material. It is not parallel with the supposed axis of the Los Palacios Basin. The wells Guanal-1 and Guanal-1A, drilled by Esso on the western end of this feature, reached a total depth of 854 and 980 m (2801 and 3215 ft), respectively. Guanal-1A was reported to have bottomed in ultrabasic igneous rocks. Some authors doubt the validity of this report (Iturralde-Vinent, 1996), however, the fact that ESSO stopped drilling both wells at such a shallow depth would confirm the presence of igneous. 8) A very strong positive gravity anomaly and the shallowest Moho in the island characterize southeastern Oriente. However, no noticeable magnetic expression exists. 9) With the exception of the Jatibonico area, the geothermal gradient is low, on the order of ±18F/ 100 ft (±28C/100 m). In the Jatibonico area (Central Depression and Trocha fault), the geothermal gradient is on the order of ±28F/100 ft (±48C/ 100 m).

5

Pardo, G., 2009, Structural geology, in G. Pardo, The geology of Cuba: AAPG Studies in Geology Series, no. 58, p. 311 – 341.

Structural Geology not applicable in unraveling the geologic history of Cuba. The only unquestionable major high-angle faults truncating the regional trends are the Pinar and the Tuinicu fault system. The Trocha and the Cauto faults, which are most commonly accepted by the geological community, are postulated on the basis of surface offsets, and perhaps geophysics, but they have never been directly observed. They may be lateral ramps or transforms joining thrust-fault segments.

In this chapter, only the surface structures that characterize the various tectonic styles will be described. Examples of subsurface structures will be shown, although very little has been published on this subject. This chapter will describe the structures in the following order: central Cuba, western Cuba, northern Cuba, and eastern Cuba. There will be a strong emphasis on central Cuba because of the availability of the 1:40,000 Gulf maps, which are detailed enough to see individual structures clearly. For the other regions, only the 1988 1:250,000 geologic map of Cuba (Pushcharovsky et al., 1988) is available, so only the general structural style can be recognized. For structural information outside of central Cuba, the available material generally shows only very small-scale drawings; generalized very small-scale cross sections and maps are characteristic of Cuban structural literature. The Tectonic Map of Cuba 1:500,000 (Pushcharovsky et al., 1989) is a good summary map. From an interpretative point of view, it shows only the case in which the basic igneous-volcanic province originated between the metamorphic massifs and the North American continent. This map, as well as the older 1985 geologic map (Cuba, 1985a), shows several large crustal faults or deep fractures cutting across all structural trends. The bases for postulating these discontinuities are many: topography, gravity, magnetics, crustal seismic, and surface geology. These deep fractures might well exist, but most of them are very questionable. They date from the 1960s when Soviet experts, who did not believe in a thrusted orogenic belt origin for the island, invoked classical Soviet-era block faulting and in-situ magmatism (a la Beloussov [Khudoley, 1967; Khudoley and Meyerhoff, 1971]). Subsequently, most of these crustal fractures have disappeared from the literature, but some of them still remain on the maps. Most such fractures probably do not exist or are

CENTRAL CUBA The tectonics of central Cuba are extremely complex; most known types of structural features are present. Each of the previously described belts has its characteristic tectonic style. Figure 169 shows the location of larger scale, but generalized, maps illustrating this chapter.

Coastal Region A relatively low structural relief appears to characterize this zone. The structures cannot be well observed on the surface because of an extensive Neogene to Holocene cover (see Figure 170). Various scattered exposures show gentle folds with dips not exceeding 308. These low-relief folds, exposing only the Caibarien* and Frio* formations in the core, are present in the Caibarien and Sagua la Chica areas. Similar folds, exposing the Casablanca Group, are present in the area north of the Cubitas Range in the Camaguey Province. Toward the south, close to the Yaguajay* belt, the folding becomes steeper, and faulting increases. This is unquestionably caused by the proximity of the Yaguajay and Las Villas faults. The folds become very steep; the flanks of the anticlines and synclines are commonly overturned to the north and to the south, and faulting becomes very common.

Copyright n2009 by The American Association of Petroleum Geologists. DOI:10.1306/13141064St583328

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FIGURE 169. Central Cuba: location of individual maps. However, three remarkable exceptions to the relatively quiet low structural relief exist. The Punta Alegre, Turiguano, and Cunagua structures bring the Jurassic evaporites of the Punta Alegre* Formation and the Cunagua salt to, or near, the surface. This indicates a structural relief of at least 10,000 ft (3000 m). These three structures are en echelon folds in line along the regional strike, that is, N658W, but each having its axis approximately east–west. The structures are associated with faulting and seem to have been active for a long time, possibly since the Maastrichtian through most of the Tertiary. Although very little is known about the Turiguano structure, each one appears to have a somewhat different character. The Punta Alegre structure is a gentle south-dipping monocline, exposing the Punta Alegre* Formation, underlain by a large south-dipping thrust that brings the Punta Alegre* Formation and Cunagua salt over Oligocene sediments. The Cunagua structure is similar, except that it has more of a diapiric aspect involving only the Cunagua salt; it appears to be rooted at the contact between the coastal belt and the Domingo*– Cabaiguan* sequences. The Turiguano structure has an irregular dumbbell shape, suggesting a dome. These

structures, which have been called diapirs, are as yet poorly understood; they could be either part of a deepseated ridge (possibly salt) associated with thrust faults or related to the postulated La Trocha fault. It should be noted that post–upper Eocene deposits in the Central Depression show appreciable folding. Diapiric structures have been reported in deep water offshore. The well Shell Manuy-1, drilled 11 km (7 mi) east of and on strike with the Punta Alegre structure, crossed at least three thrust faults that repeated the Eocene to Cretaceous section. In this general area, the Empressa de Perforacion y Extraccion de Petroleo (EPEP) drilled EPEP Moron Norte-1 some 8 km (5 mi) due west of Loma Cunagua. It is reported to have drilled through the following section: 0 to ±2690 ft (0 to ±820 m): Neogene clastics ±2690 to ±6165 ft (±820 to ±1880 m): lower – middle Eocene clastics, including conglomerates (Vega*?) ±6165 to ±9185 ft (±1880 to ±2800 m): Campanian to Albian volcanics and volcaniclastics of the Cabaiguan* sequence to where it crossed a

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FIGURE 170. Central Cuba, coastal area structures. major fault into ±260 ft (±80 m) of Paleocene coarse clastics (Vega*?) ±9185 ft (±2800 m) to total depth at 16,416 ft (5005 m): Neocomian dolomites that suggest either the Guani* Formation of the Yaguajay* belt or the upper Cayo Coco* Formation of the coastal region. Little is known about the structures along the coast. Unfortunately, the pre-1960 seismic technology was unable to resolve the structures at depth. Some of the wells (Gulf Hicacos-1, Gulf Blanquizal III-1) were located on long, linear gravity anomalies of unknown origin. Others (Shell Cayo Coco-1 and Shell Cayo Coco-2, Shell Punta Alegre-1 and Shell Punta Alegre-2, and Shell Manuy-1) were drilled on a combination of gravity and seismic reflection, with limited penetration and resolution (see Figure 171). Of the deep wells drilled along the Cays, Gulf Blanquizal III-1 had average dips of 258 and was probably cut by a thrust fault at 7650 ft (2332 m), repeating ±3000 ft (±900 m) of section. ICRM Cayo Frances-5 is reported to have crossed a thrust at ±11,510 ft (±3510 m), with a possible ±6000-ft (±1830-m) repeat, and ICRM Cayo Romano-1 is also reported to have crossed a thrust at 8397 ft (2560 m), with a possible ±10,220 ft (±3115 m) of repeat. In Shell Cayo Coco-2,

the dips average 308, and there is a possible thrust at 8349 ft (2545 m), repeating 650 ft (198 m) of section. It is obvious that these wells show structural complications and were not drilled on structure to total depth. It is possible that all the above wells crossed the same fault system that defines Cuba’s north coast. Furthermore, seismic profiles shot in deep water offshore the north coast of Cuba between Cay Sal and Cayo Coco were published by Ball et al. (1981, 1985) and Echevarria-Rodriguez et al. (1991). They show old highs, possibly bounded by reverse faults, under a younger cover. Therefore, probably, the structures under the coastal region consist of ridges, diapirs, or elongated fault blocks, bounded by south-dipping high-angle thrusts.

Yaguajay* Belt This belt is a large monocline characterized by fairly uniform south dips, ranging from 30 to 608, and by a uniform N50–708W strike. More than 12,000 ft (3600 m) of section is continuously exposed. This belt is cut by a large number of normal high-angle faults striking approximately N708E. The Yaguajay* belt is limited to the north by the Yaguajay fault zone, which strikes N578W and consists of a set of en echelon faults. South of any one of

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FIGURE 171. Central Cuba, coastal area faulting.

the individual faults, the dip is to the south, and north of the faults, it changes abruptly to the north. Within the fault zone itself is a continuous line of northward tilted blocks showing relatively little displacement in relation to the coastal region, but a much larger displacement in relation to the main part of the Yaguajay* belt. The displacement between the upthrown southern part of the Yaguajay fault zone and the coastal region is more than 10,000 ft (3000 m). The dip of the fault is unknown, but is believed to be high. The en echelon arrangement of the individual faults, the strong uptilting of a narrow belt of highly competent sediments, and the linear trend of the fault zone suggest that the Yaguajay fault has a strong lateral component, with the Yaguajay* belt displaced eastward in relation to the coastal region. The Yaguajay* belt is limited to the south by the Las Villas fault.

Jatibonico* Belt The Jatibonico* belt consists mainly of a southdipping monocline whose strike is parallel to the regional strike; it is a continuation of the Yaguajay* belt, but slightly offset to the southeast. The dips range from vertical to 508S. Some sharp folding toward the center of the belt exists.

The Jatibonico* belt is between the Jatibonico fault to the north and the Las Villas fault to the south. The Jatibonico* belt is separated from the Yaguajay* belt by a thick section of San Martin* and Vega* formations; however, these deposits must hide a fault of large horizontal displacement because the Jatibonico* belt shows facies that are coeval with, but markedly different from, those of the Yaguajay* belt. The Jatibonico fault, which in the field shows as a prominent scarp, is believed to be a high-angle fault with a throw of some 5000 ft (1500 m), which places the Jurassic to the south in contact with the basic igneous of the Domingo* sequence to the north. South of the Jatibonico* and Yaguajay* belts, the Las Villas fault dips to the south, and after passing around the eastern end of the Jatibonico* belt, it dips north toward the coastal belt. Furthermore, the Domingo* sequence rides over the Las Villas* belt thrust sheet, both south and north of the Jatibonico* belt and the eastern end of the Yaguajay* belt. The Jatibonico fault cuts both the Las Villas and the Domingo faults (see Figures 172, 173). The eastern end of the Yaguajay* belt is therefore the eastward-plunging nose of a folded and faulted stack of three thrust sheets; it is the only locality in

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FIGURE 172. Jatibonico structure. Modified from Pushcharovsky et al. (1988). See Figure 173 for cross section AA0.

FIGURE 173. Jatibonico structure cross section. See Figure 172 for definition of symbols.

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central Cuba where this structural relationship can be unequivocally demonstrated.

Sagua La Chica* Belt As already mentioned, the existence of a Sagua la Chica* belt was suspected only late in Gulf’s fieldwork, and consequently, the structural relationships were not studied in detail. No additional work on this belt has been reported. The type area where this belt is present is known as the Meneses anticlinorium; it is between the towns of Encrucijada (Sagua la Chica and Camajuani River sections) and Menesses and between the Las Villas and the Unidad faults. Along this belt, the exposures consist almost exclusively of the steeply faulted and tightly folded Sagua* Formation, showing many section repeats. This belt is probably an imbrication of, and structurally closely associated to, the Las Villas* belt. In that sense, it could be a subbelt of the Las Villas* belt. The structure will be further discussed under the Las Villas* belt section of this chapter.

Las Villas* Belt The Las Villas* belt (which included the Sagua la Chica* belt in its original definition) is bounded to the north by the Las Villas fault of still unknown horizontal displacement and dip.

Las Villas Fault The Las Villas fault is the most prominent feature of the Las Villas* belt and can be observed from west of Jumagua to the eastern end of the Jatibonico Mountains. The trace of the fault is linear, but locally it has many irregularities. The stratigraphic displacement of the fault is believed to be not very large at the fault front because it places the Sagua* conglomerate of the Las Villas* belt on Vega* Formation of the Yaguajay* belt. However, the horizontal displacement is believed to be large (as much as 30 km [18 mi]) because of the striking difference between the facies north and south of the fault. The Vega Formation is found all along the fault front, as if this formation had acted as the incompetent material on which the displacement occurred. In the Jatibonico area, the Las Villas* belt has a low north dip, cuts above relatively undisturbed Vega* Formation, and wraps around a core of both Yaguajay* and Jatibonico* belt lithologies. This is believed to be a proof for the initial low angle of the Las Villas thrust, and it is proof for later folding and faulting of this fault’s fault plane. The lower dips found on the Vega* Formation underlying the fault, the similarity between the Sagua*

found north and south of the fault, and the great differences of facies between the older formations indicate that although the fault was still active in the middle Eocene, the greatest displacement probably occurred in pre-Sagua* time (toward the beginning of the Tertiary). However, in view of the fact that the Sagua* conglomerate was, in large part, a talus deposited in deep water at the base of a carbonate scarp, the horizontal displacement of the fault during the Eocene might not be larger than a few kilometers. The folding and regional tilting of the thrust fault and of the whole Las Villas plate could explain the difference in surface expression between the eastern and western parts of the Las Villas* belt. Toward the east, the high angle of the fault would show only a steep-dipping cross section of the plate, whereas toward the west, the dip of the fault as it became closer to horizontal would show a tangential section of the plate. The Las Villas* belt can be subdivided into three major areas: The western area, extending from Panchita to Sitiecito; the central area, extending from central Corazon de Jesus to Calabazar; and the eastern area, extending from north of Vega Alta to Florencia. These three areas of the Las Villas* belt are broad regional highs separated by northward encroachments of southern belts.

Western Area The western area extends from the Sagua la Grande River to Rancho Veloz. It is characterized by one large anticlinal structure.

Quemado de Guines Anticlinorium The Quemado de Guines anticlinorium is a very large structure (see Figures 174, 175). It lies south of the Las Villas fault and is at least 37 km (23 mi) long and could extend farther northwestward toward the offshore. It is more than 8 km (5 mi) wide. It consists of three major faulted anticlines exposing Jagu ¨ ita* and Trocha* formations in the core and Sagua* Formation in the trough of the intervening synclines. The south flank of the structure exposes beds as young as the upper Vega*, whereas the northern flank is cut by the Las Villas fault. In general, the dips are on the order of 30 – 508. The faults separating the three folds are today high-angle thrusts because they place Jurassic beds to the south in contact with Upper Cretaceous to middle Eocene beds to the north. The horizontal displacement of these secondary faults must have been large enough so that the facies of the Capitolio* Formation changes to that

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FIGURE 174. Quemado de Guines, Guayabo anticlinoria. Modified from Pushcharovsky et al. (1988). See Figure 175 for cross sections AA0 and BB0.

of the Sabanilla* Formation from one anticline to the next. In the Quemado de Guines structure, the total structural relief (less than 4000 ft [1200 m]) is relatively low compared to the size of the feature. This is clearly illustrated by the occurrence of thin units such as Sagua* or Lutgarda* formations over large areas. It appears as if the structures are not deep seated, but are only folds and imbrications within a relatively thin thrust plate lying almost horizontally or dipping gently to the south. It should be noted that because of the intense compression, the Jurassic and Lower Cretaceous limestones, which are competent, show gentle dips, but are broken by a large number of faults. However, the Upper Cretaceous part of the section, which is much less competent, is very intensely and sometimes isoclinally folded and shows evidence of flowage and intrabed slippage.

Central Area The central area extends from the Sagua la Grande River to the town of Calabazar. It is characterized by several complex but readily mappable structures (see Figures 174, 175).

Guayabo Anticlinorium The Guayabo anticlinorium consists of several anticlines whose cores expose no rocks older than the Capitolio* Formation; in the synclinal troughs, beds as young as the San Martin* Formation crop out. The faulting in this anticlinorium is relatively moderate and is certainly much less intense than in the Quemado de Guines anticlinorium. The central anticline of this structure, on which Texaco spudded the Texaco Guayabo-1 well, is about 17 km (10 mi) long by more than 2 km (1.2 mi) wide. Dips on the flanks are from 30 to 508, and here again, the younger beds show

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FIGURE 175. Quemado de Guines, Guayabo anticlinoria sections. See Figure 174 for definition of symbols.

greater deformation than the older ones; the Sagua* Formation shows intense wrinkling and fracturing. In this case again, individual structures might not be deep seated; however, they show less intense deformation than in the Quemado de Guines anticlinorium. The Guayabo anticlinorium plunges steeply toward the southeast. The Texaco Guayabo-1 well bottomed at 10,010 ft (3052 m) in the Upper Jurassic, probably the Hoyo Colorado* Formation. The Las Villas fault was not reached.

Mata Anticlinorium The Mata anticlinorium resembles the Quemado de Guines anticlinorium in that it is quite compressed, and the sharp folds expose the Jagu ¨ ita* Formation in their core. Undoubtedly, these structures are not deep seated, but are part of a thrust plate. It appears to ride over the Guayabo anticlinorium.

Eastern Area The eastern area is subdivided lengthwise by the Unidad thrust fault into the northern Meneses anticlinorium and the southern Zulueta anticlinorium (see Figures 176, 177).

Meneses Anticlinorium The Meneses anticlinorium is not well known at present. It extends all the way from the Sagua la Chica River to Florencia; over most of the area, most of the outcrops are lower – middle Eocene (mostly Sagua* Formation). Here, it probably represents the Sagua la Chica* belt. The total length is more than 105 km (65 mi). The folds within this anticlinorium are of small amplitude. Toward the east, the whole belt is tilted southward, such that, in the southern flank of the Sierra de Meneses and Jatibonico, it becomes a monocline showing first a succession of repeated sections and then, finally, only one section extending from the Jurassic into the San Martin* Formation. In the Sierra de Jatibonico, the southeastern end of the Meneses anticlinorium rides over the Yaguajay* and Jatibonico* belts. To the south of the Jatibonico Mountains, the Las Villas* belt dips southward approximately 608, whereas to the north, north of the Jatibonico fault, it dips gently northward, apparently under Domingo* sequence lithologies. It can also be seen wrapping around the southeastern end of the Yaguajay* belt, separated from it by a rim of Vega* Formation belonging to the Yaguajay* belt.

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FIGURE 176. Santa Clara – Placetas area. Modified from Pushcharovsky et al. (1988). See Figure 177 for cross sections AA0 and BB0. A minimum northward displacement of 4 km (2.5 mi) for the Las Villas* (Sagua la Chica*) belt is required; however, the displacement was unquestionably greater.

anticlinorium, an imbricated thrust sheet, but dipping more steeply to the south. The original width of the Las Villas* belt, prior to faulting and folding, is difficult to establish.

Zulueta Anticlinorium

Yabu Window

The Zulueta anticlinorium is similar in scale and appearance to the Quemado de Guines anticlinorium, with the exception that individual folds are much narrower. It has been subdivided into the San Agustin anticline to the north and the Zulueta anticline to the south. The structure extends from the Camajuani River to near Iguara, or a distance of 67 km (41 mi). Sections from the Trocha* to the San Martin* formations are exposed on the flanks of the anticlines and troughs of the corresponding synclines. The Zulueta anticlinorium probably is, as is the Quemado de Guines

In addition to the main Las Villas* belt, typical Las Villas* belt lithologies have been mapped in the Yabu window showing through the Cifuentes* belt plate. This window lies between the town of Amaro and San Diego del Valle, some 8 km (5 mi) to the southwest of the nearest exposures of Las Villas* belt (see Figure 174).

Las Villas* Belt–Southern Facies The Las Villas* belt–southern facies can be subdivided into two areas of exposure (see Figures 178, 179).

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FIGURE 177. Santa Clara – Placetas area sections. See Figure 176 for definition of symbols.

Northern Area The northern area forms a very narrow linear belt of exposure and extends from southwest of the town of Camajuani to the town of Iguara. Core drilling has revealed that this belt consists of a very tightly folded and crushed syncline over most of its length, which is separated from the Las Villas* belt either by a fault, which is apparently fairly steep to the south, or by a narrow zone of Rosas* Formation. This zone contains slivers or imbrications of Las Villas* belt–southern facies lithologies. The strip of the Las Villas* belt to the southern facies is separated from the Domingo*– Cabaiguan* sequence to the south by a high-angle fault dipping 70–808 to the south. This fault has a strong horizontal component, as indicated by horizontal striations on slickensides associated with the fault. Further evidence for transcurrent displacement is given by some southwestward-pointing folds of the entire belt; these folds indicate a southeastward displacement (left lateral) of the Domingo*–Cabaiquan* sequence in relation to the Las Villas* belt. Although this fault has been shown on the map as the Domingo fault (as it marks the front of the Domingo* sequence), it is not a thrust, and the Domingo*–Cabaiguan* sequence is downdropped in relation the Las Villas* belt– southern facies. However, the tight syncline of the

Las Villas* belt– southern facies is interpreted as the folded remnant of a low-angle thrust plate that placed its lithologies over the Las Villas* belt. The Rosas* Formation served as lubricant.

Southern Area The southern area shows as a window through the Placetas* belt, 5 km (3.1 mi) southwest of the Las Villas* belt–southern facies, and is called the Fidencia anticline.

Fidencia Anticline The Fidencia anticline measures 6 km (3.7 mi) long by 2 km (1.2 mi) wide, and its axis strikes N508W. It is a very simple, regular dome; dips on the flanks do not exceed 608. This strongly contrasts with the general chaotic structures of the surrounding Placetas* belt. The fault surrounding this structure is the Placetas thrust. It should be noted that no igneous or Vega* Formation is associated with the thrust. In this particular case, the Placetas thrust is folded conformably with the structure.

Placetas* and Cifuentes* Belts In describing the structures, it is impossible to separate the Placetas* from the Cifuentes* belt because

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these are intimately associated. Several areas distinguishable by their characteristic tectonic style can be differentiated. These areas are (1) the Cifuentes plate proper, (2) the Loma Santa Fe–Placetas plate, (3) the Jarahueca structure, (4) the Loma Bonachea window, (5) the La Rana klippe, and (6) the Sierra Morena klippe.

Cifuentes Plate Proper The Cifuentes plate proper is characterized by the almost exclusive presence of Cifuentes* belt lithologies. It consists of the superposition of three, and possibly four, individual thrust plates, which appear to be gently folded. In detail, the structural conditions are extremely complex because the rocks show intense fracturing and minor folding; in many cases, several units are mixed together in what appears to be a giant breccia in which the components range in size, from a few meters to a few hundred meters across. In Pushcharovsky et al. (1988), this area has been largely mapped as the Paleocene – Eocene Vega Alta olistostrome complex. From north to south, the Cifuentes plate shows the following succession of lithologic groups: Placetas* belt (restricted to the central Macagua area), central Cifuentes* belt, southern Cifuentes* belt, central Cifuentes* belt, northern Cifuentes* belt, Yabu window, northern Cifuentes* belt, central Cifuentes* belt, and southern Cifuentes* belt (see Figures 174, 175). The above succession definitely indicates the presence of a syncline, the axis of which strikes N558W and passes near the town of Cifuentes and also an anticline of approximately parallel strike and whose axis passes through the Yabu window. A large number of strike faults exist, possibly imbrications within individual plates; however, these appear to be of relatively minor importance. However, the main thrusts separating the individual plates must have totaled a minimum horizontal displacement of 24 km (15 mi). The succession of the plates (that is, the southern Cifuentes* plate lying in the trough of the syncline and the northern Cifuentes* plate surrounding the Yabu window) clearly indicates that the displacement was from south to north. The fact that relatively thin units cover such an extensive area is believed to be evidence that, in general, the Cifuentes* plate proper is very nearly horizontal, and that the folding is of large amplitude. The area of typical Placetas* belt lithologies, in the vicinity of central Macagua, might be a direct continuation of the northern Cifuentes* plate, in which case a fourth thrust plate would not be necessary.

The Cifuentes thrust can be observed surrounding the Yabu window. The trace of the Cifuentes thrust, however, does not constitute the northern boundary of the Cifuentes* belt. This boundary consists of an area of varying width, but commonly very narrow (on the order of a few hundred meters), where igneous rocks of the Domingo* sequence, including granodiorite and some serpentine, are tectonically mixed with the Vega* Formation belonging to the Las Villas* belt. Core drilling has shown that the fault separating the Cifuentes* belt from the igneous rocks is commonly steep, more than 608S, but can be as low as 358S. Along this fault zone, toward the Las Villas* belt, is intense deformation, such as squeezing out of entire formations and boudinage phenomena. Within the fault zone are several high-angle faults, which seem to be parallel to the strike of the fault zone itself. This suggests that at present, the northern boundary of the Cifuentes* belt is caused by late middle Eocene faulting, which truncated the original trace of the Cifuentes thrust. As will be seen later, the fragmentary outcrops of the Domingo* sequence are believed to have been faulted down from above and caught in the fault zone, whereas the Cifuentes* belt was being upthrown after the main thrusting was completed. It should be mentioned that north of Sitiecito, there is a klippe of Cifuentes* belt, 5 km (3.1 mi) long by 1.5 km (1 mi) wide, which is separated from the main Cifuentes* belt by 2 km (1.2 mi) of exposure of Domingo* sequence lithology. The Domingo thrust bounds this klippe to the south. The displacement of the Cifuentes* belt proper over the Las Villas* belt is difficult to estimate. However, considering the position of several thrust plates, a minimum displacement of 40 km (25 mi) of the southern Cifuentes* belt plate in relation to the Las Villas* belt is necessary. This displacement is an absolute minimum. Individual belts do not show any appreciable facies change across their strike, whereas marked facies differences are obvious from plate to plate.

Loma Santa Fe–Placetas Plate In this plate, which is a southeastward continuation of the Cifuentes plate proper (see Figures 176, 177), Placetas* and Cifuentes* belt lithologies occur together. In the Encrucijada area (see Figure 174), this plate encroaches deeply over the Las Villas* belt. This encroachment is parallel to a similar displacement of the Domingo* sequence at Sitiecito (see Figure 178), which suggests the presence of north–south faults that are not clearly defined in the field because they

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FIGURE 178. Camajuani-Tamarindo area. See Figure 179 for cross section AA0.

are probably wide zones of shearing. However, they appear to have downdropped the Placetas* belt in relation to the Las Villas* belt. The structure within this part of the plate is poorly defined but seems to be anticlinal with a general strike of N358W. Typical lithologies of the Cifuentes* and Placetas* belts occur intermixed; however, typical Placetas* belt lithologies are dominant. In this plate, the structural details are again impossible to discern because of intense

crushing. In general, the structure is that of an anticline, as shown by the Las Villas* and Placetas* belt window of the Fidencia anticline, which lies more or less in the center of the Loma Santa Fe – Placetas plate. Southeast of Placetas, this plate shows a marked Z-fold, which, although cut by several faults, is considered an expression of two eastward-plunging anticlines overlain by Domingo* and Cabaiguan* sequence lithologies.

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Cunagua?

?

?

FIGURE 179. Camajuani – Tamarindo area. See Figure 178 for definition of symbols.

The Jarahueca fault, a reverse fault dipping 50 – 758S, bounds the Loma Santa Fe – Placetas plate to the north. The Jarahueca fault is definitely a late fault, which truncated the original Placetas thrust, upthrowing the Placetas* and Cifuentes* belts in relation to the Domingo* sequence. The Jarahueca fault is similar to the fault north of the Cifuentes plate proper, except that there was less erosion of the stack of plates, thus showing a much greater development of the Domingo* sequence than in the Cifuentes area. As will be seen later, there is little doubt that at one time, the Domingo* sequence was thrusted over the Placetas* and Cifuentes* belt plates (and possibly over much of the Las Villas* belt), but has since been mostly eroded. Therefore, generally speaking, the Loma Santa Fe–Placetas plate can be considered a faulted anticline, whereas the area between this plate and the Las Villas* belt can be considered as a tectonic low. The true Placetas thrust is only visible surrounding the Fidencia anticline; it might be the equivalent of the Cifuentes thrust. South of the Jarahueca fault are some elongated bodies of Domingo* sequence lithologies running parallel to the regional strike. Slivers of Placetas* belt lithologies within the Domingo* sequence, immediately north of the Jarahueca fault, also exist; these are believed to be Jarahueca fault imbrications. A possibility exists that the Loma Santa Fe–Placetas plate is bounded to the south, in the vicinity of Placetas, by a high-angle transcurrent fault. This fault can be seen to cut the Z-fold southeast of Placetas. This suggests that the southern part of the Z, which has approximately the same length as the northern part, was displaced some 10 km (6 mi) to the southeast (left lateral) in relation to the main Loma Santa Fe– Placetas plate.

Jarahueca Structure The Jarahueca structure is a feature 26 km (16 mi) long by 3.5 km (2.1 mi) wide, striking N458E (see Figure 179). It forms a crushed anticlinorium in which the core consists of Placetas* belt lithologies, and the flanks, generally speaking, are made of central Cifuentes and southern Cifuentes plate lithologies. Hatten et al. (1958) called it the Jarahueca Fenster. Toward the southeastern end of the Jarahueca structure, a large outcrop of the Tre´s Guanos granodiorite exists. It is considered part of the pre-Neocomian basement of the southern Cifuentes plate. Therefore, here again, as in the Cifuentes plate proper, there is a superposition of three thrust plates, the southern Cifuentes plate being the uppermost. The structure of the anticlinorium is complex, imbricated with near-vertical dips, and cut by several strike faults. The Jarahueca structure is bounded to the south by the same Jarahueca fault previously described, which appears to die out toward the southeastern end of the structure, and to the north by what is believed to be a Placetas* belt imbrication. The dip of the Jarahueca fault is unknown, but an angle of 608S at the northwestern end of the structure was encountered. Toward the southwest, the Jarahueca structure is surrounded by lithologies of the Domingo* and Cabaiguan* sequences. This is an additional proof of the superposition of the igneous and volcanic belts over the limestone belts.

Loma Bonachea Window The Loma Bonachea window shows a very steep half dome in which Cifuentes* belt lithologies surround Placetas* belt lithologies (see Figure 176). This window is surrounded on all sides by Domingo* sequence lithologies, consisting of brecciated Miguel*

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Formation mixed with metamorphic blocks and serpentine containing metamorphic exotics. The rocks showing through the window are highly sheared, showing evidence of flowage. The Loma Bonachea window is a southeastward continuation of the Cifuentes plate proper and is part of what was called the Cruz anticline.

The magnitude of the displacement relative to the Las Villas* belt must have been at least 40 km (25 mi); however, allowing for facies changes from one plate to the next, a displacement of 80 – 100 km (49– 62 mi) is more likely.

La Rana Olistolith(?)

Tectonically, these sequences cannot be separated. For clarity of the description, the Domingo* and Cabaiguan* sequences will be subdivided into the following areas: (1) the Mayajigua area, (2) the CamajuaniTamarindo area, (3) the Santa Clara – Placetas area, (4) the Seibabo–Cabaiguan area, (5) central Camaguey area, and (6) the northern Escambray area.

The La Rana olistolith(?) consists of a small area of southern Cifuentes plate lithologies (including the best documented pre-Neocomian granodioritic basement outcrop in central Cuba) lying in the trough of a syncline of the Cabaiguan* sequence (see Figure 179). It is surrounded by the Maastrichtian Carlota* Formation, but is apparently overlain by the upper Maastrichtian Jiquimas* Formation and by the Paleocene Taguasco* Formation. This feature is poorly understood because it is surrounded by rocks of the Cabaiguan* sequence. It appears to be of late Maastrichtian – Paleocene age, whereas most of the other thrusts are of Paleocene to lower– middle Eocene age. It could be a slump block within the Taguasco* Formation derived from the nearby Jarahueca structure.

Sierra Morena The Sierra Morena (Socorro complex) consists of a large area (12
4 km; 7
2.5 mi) of southern Cifuentes* belt, including pre-Middle Jurassic granite with Precambrian marble inclusions, overlain by Neocomian Jobosi* conglomerates and Ronda* Formation (see Figure 178). Pszczo´lkowski (1983) mapped a stack of low-angle thrust sheets, the highest (La Sierra) consisting of Jobosi* (Constancia), Ronda* (Veloz), and Santa Teresa* riding over a granite sheet (Socorro), which, in turn, rides over another sheet of Ronda*. This Cifuentes* belt complex rides over the Las Villas* belt to the north. It is centered on a large gravity minimum. In conclusion, the Cifuentes* and Placetas* belts have a tectonic style characterized by a succession of relatively flat-lying thrust plates, forming low-amplitude folds of relatively large wavelength. In detail, the tectonic pattern of this plate is very chaotic, but the largescale structural features are persistent over large distances. The Cifuentes*–Placetas* belt outcrops between the Las Villas* (and Las Villas*– southern facies occasionally) and the Domingo* and Cabaiguan* sequences. These three major belts were folded and faulted after thrusting, producing windows and klippen. The displacement of the plates was unquestionably from south to north because southern facies plates consistently overlie northern facies plates.

Domingo* and Cabaiguan* Sequences

Mayajigua Area Very little is known about the Mayajigua area (see Figure 172). It is part of a klippe of Domingo* sequence lithologies, which lies on the coastal area north of the Yaguajay* and Jatibonico* belts, north of the Jatibonico Mountains. The previously mentioned EPEP Moron Norte-1 well near the town of Moron, 30 km (18 mi) to the east, found Cabaiguan* sequence volcanics over the coastal area sediments.

Camajuani–Tamarindo Area This area consists of a mixture of Domingo* and Cabaiguan* sequence lithologies. It is bounded to the north by a fault that separates it from the Las Villas* belt and Las Villas–southern facies (see Figure 179). Toward the northwest, this fault has a high angle; however, toward the southeast, there are indications that it dips southward at a lower angle. To the south, Domingo* and Cabaiguan* sequences are separated from the Placetas* belt by the Jarahueca fault. This area of exposures of Cabaiguan* and Domingo* sequence lithologies can be considered a faulted synclinorium striking N358W and plunging toward the southeast. The structural details are very complex: there is evidence of high compression, and strike faults are common. A narrow anticline runs along the center of the synclinorium for practically its whole length, passing through Andre´s and south of the towns of Jarahueca and Venega. It should be emphasized that in this area, formations, which outcrop extensively south of the Cifuentes* and Placetas* belts, have been definitely identified (the fossiliferous Cenomanian Gomez* Formation among them). These formations, belonging to the

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volcanic section, are of the same age as formations of the Placetas* and Cifuentes* belts. This shows that the thrust plate, which displaced the volcanic facies, moved a long distance northward over the limestone facies. Considering the present-day exposures of the Domingo*–Cabaiguan* sequence in relation to the limestone belts, a minimum northward displacement of 25 km (15 mi) is required; however, the true displacement probably was much greater. Toward the southeast, the area of Domingo* and Cabaiguan* sequence exposures continues into the Seibabo –Cabaiguan area through a well-developed anticline, which is the continuation along the strike of the Jarahueca structure. This anticline shows, toward the northwest, the Placetas* and Cifuentes* belt in the core of the Jarahueca structure and on the flanks, successively, Domingo* sequence lithologies, Lower Cretaceous(?) volcanics, and Maastrichtian volcanics. This anticline is extremely broad and plunges to the southeast. It is cut by numerous faults; the Domingo* sequence lithologies, as well as the older volcanics, show more intense deformation than the Maastrichtian rocks.

Santa Clara–Placetas Area The Santa Clara–Placetas area, which has a roughly triangular shape, is in the vicinity of Santa Clara and Placetas and extends almost as far north as the central Constancia. Here, rocks of the Domingo belt form most of the outcrop. Several features are present: (1) the Escambray anticline, (2) the Santa Clara syncline, (3) the Cruz anticline, (4) the Manajanabo syncline, and (5) the Falcon syncline (see Figures 176, 177).

The Escambray Anticline The Escambray anticline (not to be confused with the Escambray massif farther to the south near the towns of Trinidad and Sancti Spiritus) is a large feature 28 km (17 mi) long by 12 km (7 mi) wide whose axis strikes N558W and plunges to the northwest. This anticline exposes mostly metamorphic rocks and a mixture of serpentine and metamorphics. It is bounded to the south by the Guaracabulla fault that dips to the north, therefore upthrowing the Escambray anticline in relation to the Cabaiguan* sequence. The anticline includes minor folds such as the Espanto syncline and the Corojo anticline. The Escambray anticline is believed to expose the lowest level of the Domingo* sequence. Because of its numerous oil and gas seeps, Gulf believed it offered the best prospect in central Cuba for drilling to the supposed underlying carbonate plates. In 1955, Gulf’s

Sullivan-8 core hole was drilled in serpentine to 2343 ft (714 m) and had a large oil show near the surface. In 1956, a Consolidated Cuban Petroleum Corp. farm out from Gulf, Escambray-1, was drilled nearby in serpentine and metamorphics to 5053 ft (1540 m) where it was abandoned for mechanical reasons. To my knowledge, no deeper well has ever been drilled in this location.

The Santa Clara Syncline The Santa Clara syncline has an axis roughly parallel to the Escambray anticline (N708W) that plunges to the northwest (Gulf sheet 11-D). The trough of this feature is filled with Cabaiguan* sequence and lower to middle Eocene sediments. The width of the Santa Clara syncline north of the town of Santa Clara is approximately 8 km (5 mi). The Santa Clara is parallel to the Cruz anticline to the north.

The Cruz Anticline The core of the Cruz anticline is the Loma Bonachea window, which is surrounded by a zone of brecciated Miguel* Formation mixed with metamorphic blocks. This anticline, which is on strike with the Cifuentes plate proper, swings southward at Loma Bonachea until the axis strikes N158W. Although several faults are obvious, the base of the Domingo* sequence is mostly represented by the Domingo thrust. The Cruz anticline axis plunges southward. Toward the west, the Manajanabo syncline follows the Cruz anticline.

The Manajanabo Syncline The Manajanabo syncline is more than 30 km (18 mi) long by 23 km (12 mi) wide, strikes N158W, and plunges toward the south. The trough of the syncline is filled with Cabaiguan* sequence sediments. This syncline is limited to the northeast by what is believed to be the trace of the Domingo fault; however, here again, high-angle faulting and possibly flowage phenomena in the serpentine have modified the original nature of the thrust. This syncline is followed to the south by the Falcon syncline.

The Falcon Syncline The Falcon syncline is a very interesting feature, formed by a thrust plate of Cabaiguan* and Domingo* sequences lithologies resting in the trough of the Manajanabo syncline. The fault itself is clearly indicated by a semicircular narrow strip of serpentine around a normal sequence of Domingo* and Cabaiguan* sequence lithologies. No rocks younger than

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Maastrichtian are present under the serpentine rim, indicating that the thrusting was late Maastrichtian, certainly before the Paleocene. The Falcon syncline is bounded to the south by the prolongation of the Guaracabulla fault and has taken a somewhat bowl shape, whose long axis strikes approximately east–west. The Falcon syncline is cut by several minor faults. In conclusion, the Santa Clara – Placetas area represents a regional high that was uplifted probably at the same time that the Guaracabulla fault was active. From west to east, the strike of the structures shifts from N558W to N158W, and simultaneously, the axes of the structures plunge in opposite directions: the Escambray anticline and Santa Clara syncline plunge to the northwest, and the Cruz anticline and Manajanabo syncline plunge to the south. This change in direction was accomplished at the expense of great fracturing and possibly flowage along the central part of the area. The Loma Bonachea window is clear evidence that the Domingo* and Cabaiguan* sequences were extensively thrusted over the limestone belts, and this is an indication that the whole Santa Clara–Placetas area might be underlain, at not too great depths, by the limestones of the northern belts. The Falcon syncline indicates that low-angle thrusts were also present within the Domingo* and Cabaiguan* sequences.

Seibabo-Cabaiguan Area This area contains most of the Cabaiguan* sequence proper.

The axis of the Seibabo syncline plunges toward the northwest.

La Rana Syncline The La Rana syncline is located northeast of Cabaiguan and south of the Jarahueca structure (see Figure 179). It is broken by numerous faults; its north flank consists of Domingo* sequence lithologies, whereas its south flank is cut by poorly understood faults. Paleocene to middle Eocene rocks are preserved in the trough, and a fragmentary Cabaiguan* sequence section is preserved on both flanks. The strike of the syncline is N508W, and its axis plunges toward the southeast. The northwestern end of the syncline, northwest of Potrerillo, shows Cabaiguan* sequence lithologies surrounded by Domingo* sequence lithologies and, from northwest to south, by the Placetas* belt. This particular area where the Jarahueca fault truncates the syncline to the north is another typical example of the superposition of thrust sheets. Near Cabaiguan and toward the northwest, the structure is uninterpreted because of the lack of obvious markers; however, block faulting and largescale folding do occur. West and south of Cabaiguan, starting near the town of Fomento, a syncline is present; it appears to be a branch of the Seibabo syncline. Near the town of Cabaiguan and north of the town of Jatibonico, the Cabaiguan* sequence forms a large syncline containing intensely folded and faulted Tertiary rocks.

Seibabo Syncline The Seibabo syncline is a large syncline, west of Cabaiguan, more than 40 km (25 mi) long by 14 km (8.7 mi) wide (see Figures 180, 181). The steeply northdipping, reverse Guaracabulla fault separates it from the Escambray anticline. The north flank of this syncline dips steeply to the south and sometimes is overturned, whereas the south flank dips from 30 to 508 to the north. The axis of the syncline strikes N508W. The center of the syncline is cut by a large number of normal and thrust faults that divide the structure into independent blocks. Some major faults are cutting completely across the syncline, some of which show as much as 2 km (1.2 mi) of lateral displacement. The strike of the most important thrust fault is northnorthwest and dips northeast. It is an imbrication of the Guaracabulla fault. Abundant evidence for intrabed slippage also exists. This syncline shows evidence of southward pushing from the serpentine mass.

Central Camaguey Area In the central Camaguey area, the outcrops do not show the large-scale structural diversity obvious in Las Villas and western Camaguey provinces. The Domingo* sequence is largely in contact with the Yaguajay* belt to the north. As in western Camaguey, the Domingo fault (Cubitas fault) appears to wrap around the southeastern end of the Yaguajay* belt (Cubitas Range). Toward the northwestern end of the ultrabasics, Pushcharovsky et al. (1988) show several linear exposures of Jurassic–Lower Cretaceous limestone called the Esmeralda complex. These were interpreted by Gulf as being windows showing the Las Villas* belt through the Domingo* sequence. Toward the southeastern end of the ultrabasic body is a large window, called Loma Camajan, exposing the Las Villas* belt to the north and Cifuentes* belt to the south.

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FIGURE 180. Seibabo syncline. See Figure 181 for cross section AA0.

The Cubitas fault used to be considered a southwarddirected thrust (Flint et al., 1948), and Loma Camajan was a klippe of Cubitas limestones over the ultrabasics. South of the Domingo* sequence, the Cabaiguan* sequence, mostly represented by Upper Cretaceous volcanics, shows a nearly continuous band of granodiorite, whose outcrops run from Ciego de Avila to Las Tunas in Oriente. This granodiorite intruded all the pre-Maastrichtian rocks. The contact between the Domingo* and Cabaiguan* sequences is not clear; with the exception of some Campanian volcanics that appear to lie over the ultrabasics, these two belts appear to be separated by a major fault.

Northern Escambray Area The outcrops of the northern Escambray area, south of the Cabaiguan* sequence and north of the Escambray massif (see Figures 180, 181), consist mainly of a large linear body of Upper Cretaceous Sancti Spiritus granodiorite and the Mabujina amphibolite. The granodiorite has an intrusive relationship with the older volcanics of the Cabaiguan* sequence as well as with the Mabujina amphibolite. The granodiorite is also in fault contact with the Upper Cretaceous and the lower – middle Eocene of the Cabaiguan* sequence, the Tuinicu fault. It is very important to remember that along this fault, south of the town of Guayos,

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FIGURE 181. Seibabo syncline. See Figure 180 for definition of symbols. large outcrops of unmetamorphosed Ronda* and Jagu ¨ ita* formations from the Cifuentes* and Las Villas* belts exist. Near the fault zone, Tertiary conglomerates contain fragments of these formations as well as fragments of the Jobosi* Formation. The Mabujina is believed to be equivalent to the Domingo* sequence and to be the basement over which the Cabaiguan* sequence was deposited. The basic igneous-volcanic province is in fault contact with the Escambray metamorphics that it overlies on three sides. There is no question that this province overrode the Escambray massif; however, there is no direct field evidence whether it was from south to north or north to south. In conclusion, the Cabaiguan* and Domingo* sequences are structurally characterized by a high toward the north, where Domingo* sequence lithologies are brought near the surface and are structurally mixed with the limestone belts. This area is, generally speaking, the area of exposure of the trace of the Domingo thrust fault. Toward the north, evidence for northward thrusting is found. However, toward the south, Domingo* sequence lithologies are deeply buried under a large asymmetric syncline, which shows evidences of southward thrusting. This peculiar tectonic style of the Cabaiguan* sequence does not show as much intense deformation as the Domingo* and Cabaiguan* sequences show to the north. This southward push could be related to later deformation of the thrust plate if all the thrusting was directed toward the north or be evidence that thrusting was also directed southward. The Santa Clara – Placetas area represents a regional structural high from which all the structures plunge away. The southwestern limit of the Domingo* and Cabaiguan* sequences is characterized by large N758E-striking faults passing in

the vicinity of Arroyo Blanco. These faults are possibly normal or transcurrent faults with a downthrown south side. It should again be emphasized that a minimum northward thrusting of 25 km (15 mi) is necessary, with the possible displacement of the Domingo* and Cabaiguan* sequence thrust plate over the limestone plates on the order of 50 km (31 mi) or more. Most displacement during the orogeny probably occurred along the Domingo thrust, and the distance between the original position of the basic igneous-volcanic province facies and the carbonate platform province facies must have been shortened by a minimum of 150–200 km (93–124 mi). This shortening of the basin seems great, but if considered in relation to the total length of the orogenic belt, which extends from Central America to the Lesser Antilles, it does not appear so much out of proportion (Figure 182).

Escambray Metamorphics As in Chapter 2 of this publication, the following section is mostly based on the excellent work of Guillermo Milla´n and Mark Somin conducted from 1977 to 1990. Pushcharovsky et al. (1988) is also based on their work. The Escambray massif is in large part made up of generally low-grade metamorphics that have been fairly well dated and correlated with the unmetamorphosed Upper Jurassic – Lower Cretaceous section of Pinar Del Rio. No similar rocks have been reported elsewhere in the central Camaguey province. The internal structure of these two domes is very complex with steep radially directed dips. The Trinidad and the Sancti Spiritus domes have been subdivided into six structural units each, for a total of eight units (four units are common to both domes)

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(see Figures 106, 107). These units are interpreted as folded and faulted superimposed thrust sheets. Each dome has also been subdivided into three metamorphic zones where, generally speaking, zone I, the lowest grade, is in the center of the western domes and zone III, the highest grade, is on the periphery of both. From the center of the domes outward, the metamorphic grade of the structural units increase from zone I to zone III, giving the impression of inverse metamorphism, which was the original interpretation. However, an exception is observed; the outermost structural unit (unit 6) has a lower metamorphic grade. The metamorphism is described as high pressure – low temperature. The zones, which have been described in Chapter 2 of this publication, are summarized as follows: Zone I: This zone, internal units 4– 6, shows little recrystallization and much preservation of the original texture. The shales show preservation of the original sedimentary structures with little or no schistosity. Zone II: This shows complete recrystallization. The sedimentary schists have white mica and occasionally chlorite and sometime show remnants of the original structures, exhibiting the same minerals found in zone I, plus lawsonite. Zone III: This zone, external unit 1, shows that in the sedimentary schists, chlorite has disappeared, and albite can be abundant. Quartz-albite-white mica schists are common. Some crystalline schists contain garnet, glaucophane, diopside, hornblende, clinozoisite, epidote, zoisite, and lawsonite. In the metabasic rocks, hornblende is present instead of actinolite and so are glaucophane, garnet, clinozoisite-epidote, white mica, diopside, zoisite, and lawsonite. Quartzites can have garnet, magnetite, glaucophane, riebeckite, hornblende, zoisite, clinopyroxenes, and diopside. White mica is always present. In marbles, zoisite is occasionally present. Figure 108 shows, from the center of the domes (units 4–6) toward the rims, the order of the structural units and, schematically, the lithologies of the original sediments. In general, units 2, 3, and 4–6 are the internal units, whereas units 1 and 2 are the external ones. The degree of metamorphism decreases toward the center. However, as of this date, no direct proof of the direction of thrusting exists. The age dates of the metamorphics range from 43 ±5.0 to 85 ± 4.7 Ma, with a median of 68 Ma or upper

Maastrichtian–lower Paleocene, and there is evidence that some deformation happened prior to the metamorphism, whereas most of it was simultaneous with it or later. It was generally believed that the Sancti Spiritus granodiorite, associated with the Upper Cretaceous volcanics of the Cabaiguan* sequence, was related to the process responsible for the metamorphism of the Escambray massif. However, as already mentioned, the age of the granodiorite body has been determined to have a median value of 84 Ma in Las Villas, and 78 Ma in Camaguey, or upper Santonian to lower Campanian. This, together with the lowtemperature type of metamorphism, definitely suggests that the Escambray metamorphism was more related to the overriding oceanic basement plate than to the arc volcanism. Millan and Somin (1981) originally proposed this idea. The question of why the Escambray sediments were metamorphosed, whereas the Las Villas, Placetas, and Cifuentes that were also overridden were not, remains. A possible explanation might be that the oceanic plate had cooled by the time it reached the edge of the basin.

CENTRAL CUBA DISCUSSION Figure 183 shows a simplified, composite, north – south cross section from Cayo Coco through the Escambray massif, with a minimum of interpretation. The most important structural elements are shown. The Jurassic platform carbonates and the Cifuentes* belt are shown under the Tuinicu fault only to explain their presence as exotics along the fault plane. Central Cuba therefore shows evidence of the presence of a deformed stack of thrust sheets underlying the Domingo* and Cabaiguan* sequence. It must be emphasized that the Yaguajay, Sagua La Chica, Jatibonico, and Las Villas* belts form fairly coherent structures. So do the Domingo and Cabaiguan sequences south of Santa Clara. However, the structures of the Placetas and Cifuentes belts, as well as the intervening imbrications of the northern basic igneous-volcanic province are extremely chaotic. Some authors have called them olistostromes. These relatively thin, deep-water sediments appear to have been crushed under the slab of advancing oceanic basement, a ‘‘traineau ecraseur’’ (crushing sled). Figure 184 illustrates a possible mechanism of structural development assuming an overriding slab of oceanic crust. Additionally, these thrust sheets seem to have been considerably compressed, cut by high-angle and transcurrent faults. This zone of superimposed deformation coincides with the suture and must have happened

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FIGURE 182. Sierra Morena area. during the final phase of tectonism in the middle Eocene. It is not clear if this is caused by the Bahamas Bank buttress or other plate motions. All the platform to deep water province, as well as the northern basic igneous-volcanic province, thrust sheets have definitely been thrust northward, whereas the Do-

mingo* and Cabaiguan* sequences exposed in the Seibabo syncline show evidence of southward movement. Whether the basic igneous-volcanic province was entirely thrust northward or extruded north and south from a nearly in-situ rift (Iturralde-Vinent, 1996) is still debatable. Two conflicting pieces of evidence exist:

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FIGURE 183. Central Cuba cross section. See Figure 169 for location of cross section. (1) the Upper Jurassic Jagu ¨ ita* detritus in the Cenomanian Cristobal* Formation of the Cabaiguan* sequence supporting an in-situ rift and (2) the outcrops of unmetamorphosed Jagu ¨ ita* and Ronda* formations along the Tuinicu fault supporting a southern origin for all thrusting. The Bouguer gravity (Figure 157) shows some interesting features that are worth comparing with the outcrops: 1) The Yaguajay and part of the coastal belts lie on the south flank of a regional gravity high of which the axis is approximately parallel to and near the outer lines of keys. This gravity high might be related to the fault zone along the north coast of Cuba (high-angle reverse faults?). 2) Most of the low-angle thrust plates of the northern belts coincide with a strong regional gravity low (10 to 20 milligals). The coincidence between the gravity low and the area of carbonate thrust plates indicates that basement must be at a great depth, possibly more than 30,000 ft (9000 m), and that under the relatively thin Cifuentes* and Placetas* belt thrust plates, a full development of Las Villas*, Jatibonico*, and Yaguajay* belts could

be present. The granodiorite near Sierra Morena, which is considered a slice belonging to the southern Cifuentes* belt plate and lies in the trough of a syncline, coincides with the lowest value (30 mG) of the regional gravity low. 3) The granodiorite near Sierra Morena, which is considered a slice belonging to the southern Cifuentes* Belt Plate and lies surrounded by sediments. It coincides with the lowest value (30 milligals) of the regional gravity low. This suggests the presence of a thick stack of thrust plates. 4) In the Motembo area, the Domingo sequence coincides with a regional gravity high. This suggests the presence of a considerable amount of ultrabasic igneous in the subsurface. 5) A narrow strong linear gravity low exists (as low as 30 mG), which extends from the south of Sancti Spiritus to the north of Ciego de Avila. This gravity low coincides with the Central Depression, and the lowest gravity values are where Tertiary deposits are relatively thin. It is parallel to the postulated La Trocha fault system, which, near Arroyo Blanco, marks the southwestern termination of the Domingo* and Cabaiguan* sequences exposed in the Las Villas province. This gravity

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FIGURE 184. Central Cuba, diagrammatic structural evolution. low, believed to be related to the faulting, is possibly the reflection of a deep-seated graben. 6) Considering the trend of the granite outcrops, which ends near Sancti Spiritus and reappears again near Ciego de Avila and Florida and the

offset of the Yaguajay* belt, it would seem as though the Trocha fault zone has several kilometers of left-lateral displacement. However, this fault zone has never been well defined in the subsurface.

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7) The granodiorite and volcanic outcrops northwest of Sancti Spiritus, Ciego de Avila-Florida, and south-central Camaguey coincide with a strong regional gravity high. This, contrasting with the gravity low under the granite outcrop of Sierra Morena, would suggest that these granites and volcanics are deep seated. 8) The Domingo* sequence in the central Camaguey province again coincides with a pronounced gravity low (30 milligals). This suggests an accumulation of thrust plates involving material other than basic igneous material. 9) The Escambray metamorphics are represented by generally low Bouguer anomalies. This, perhaps, reflects an accumulation of dominantly quartzosa thrust sheets, over a deep granitic basement.

WESTERN CUBA For structural purposes, western Cuba has been subdivided into the Guaniguanico Mountains (including the Bahia Honda area in western Habana), the Los Palacios Basin, and the Isle of Pines.

Guaniguanico Mountains The overall structure of the Guaniguanico Mountains in western Cuba is characterized by a very broad anticlinorium consisting of a stack of thrust sheets. The stratigraphy of these individual thrust sheets (or tectonic units) is described in Chapter 2 of this publication. Based on the stratigraphy, five major thrust plates have been recognized; in ascending order, they are 1) 2) 3) 4) 5) 6)

the Sierra de los Organos belt (Mogotes area) Sierra de los Organos belt (Pizarras del Sur area) Cangre belt southern Rosario belt northern Rosario belt La Esperanza belt (equivalent to northern Rosario belt) 7) Guajaibon – Sierra Azul belt 8) Domingo* and Cabaiguan* sequences These major thrust sheets have been subdivided into smaller scales or tectonostratigraphic units with a more restricted distribution. These scales are variable in size and limited in geographic extent; they are like large olistoliths and do not extend the whole length of the belt; these, from lower to upper unit, are summarized in the following sections. They are shown in Figure 185.

Sierra de Los Organos Belt Mogotes Area The Sierra de los Organos belt, Mogotes area, has been subdivided into nine superimposed thrust sheets or scales: 1) Pinar-1 unit. It is the lowest unit and is only known from the deep well EPEP Pinar-1. It has not been formally named, and the name Pinar-1 is used in this report. It underlies the Valle de Pons unit, and its base is unknown. The dips are generally low. 2) Valle de Pons unit. Its upper part is known from outcrops in the Pons Valley, but the lower part is only known from Pinar-1. Because of a repeat of section in the well, Pszczo´lkowski (1999) considers that two units are involved. This unit is probably equivalent to the outcrops exposed in the Los Portales window in the southwest of the Mogotes belt. It underlies the Quemado, Infierno, Vin ˜ales, and Pizarras del Norte units. 3) Quemado unit. It outcrops only south of the town of Pons where it overlies the Valle de Pons unit. It underlies the Infierno unit. It is probably equivalent to the Paso Real unit in the southwestern Mogotes belt that overlies the Los Portales outcrops and is overlain by the Guane unit. 4) Infierno unit. It occurs mostly in the south-central part of the Mogotes belt and overlies the Valle de Pons and Quemado units. To the southwest, the Guane unit is considered equivalent to the Infierno. A minor structural subunit is named the Celadas unit. 5) Vin ˜ales unit. This is the most extensive of the carbonate units and overlies the Infierno and the Valle de Pons units. It underlies the Anco´n, Pico Grande, and Pizarras del Norte units. 6) Sierra la Gu ¨ ira unit. It occurs in the northeast of the Mogotes belt. It lies over the Vin ˜ales unit. It underlies the Loma del Puerto, Los Bermejales, and Pizarras del Sur units of the southern Rosario belt. Toward the southwest, it overlies the Pizarras del Sur that is believed to be a local structural phenomenon. 7) Pico Grande. This unit occurs between the Vin ˜ales and Anco´n units. It is the lower part of the original Rigassi-Studer (1963) Anco´n unit. Toward the east, it underlies the Loma del Puerto and La Paloma units of the southern Rosario belt. 8) Anco´n unit. It is the highest carbonate unit in the Mogotes belt. It is developed mostly toward

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FIGURE 185. Structural subdivisions of western Cuba.

the northeast, where it underlies the La Paloma unit of the southern Rosario belt. 9) Limonar-Cayo las Damas window. This long and narrow window through the Pizarras del Norte subbelt extends from La Palma to south of Mantua. It shows mostly the underlying Manacas Formation and other outcrops of unidentified lower units.

Pizarras del Sur Area The Pizarras del Sur area is the southern equivalent of the Loma del Muerto and La Llave units (Pizarras del Norte) of the southern Rosario belt. It consists of all the unmetamorphosed San Cayetano outcrops south of the Mogotes belt and north of the Pinar fault. The thick, monotonous San Cayetano is intensely folded and faulted.

Cangre Belt The narrow Cangre belt is called the Cangre unit in Pushcharovsky et al., 1988 (and other publications). It is present along the northern upthrown side of the

Pinar fault and extends for some 72 km (44 mi). It has been subdivided into two units: 1) Mestanza unit. It is a thin, south-dipping thrust sliver wedged between the Pizarras del Sur belt and the Pino Solo unit. It is characterized by a thin Jurassic carbonate section and by some degree of metamorphism. 2) Pino Solo unit. It extends for 70 km (43 mi) along the Pinar fault and represents the uppermost and most metamorphosed thrust sheet of the Pizarras del Sur belt. North of it is a klippe of the same subunit named the Cerro de las Cabras unit.

Northern Rosario Belt The northern Rosario belt has been subdivided into seven low-angle mostly north-dipping thrust sheets or units: 1) Belen Vigoa unit. This is the lowest of the sequence and overlies the southern Rosario belt. It is overlain in the east by the Naranjo and in the west by the Cangre units.

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2) Naranjo unit. It generally overlies the Belen Vigoa unit and, to the east, the southern Rosario belt. From east to west, it underlies the Dolores, La Serafina, and Cangre units. 3) Dolores unit. It is limited to the eastern part of the northern Rosario belt, where it overlies the Naranjo unit, and is overlain by the La Serafina unit. 4) La Serafina unit. It is also limited to the eastern part of the Rosario belt and is mostly underlain by the Dolores unit and overlain by the Cangre unit. 5) Cangre unit. The Cangre unit (the name Cangre Belt has been used for the metamorphic equivalent of the Pizarras del Sur belt.) is rather extensive and covers two-thirds of the northern Rosario belt. From east to west, it underlies La Serafina, Naranjo, and Belen Vigoa units and the southern Rosario belt. Between the Cangre and the Naranjo units is a large elongated serpentine body. Everywhere, the Cangre unit underlies the Sierra Chiquita unit. The name Cangre belt has been used for the metamorphic equivalent of the Pizarras del sur belt. 6) Sierra Chiquita unit. Extending for the entire length of the northern Rosario belt, it is underlain by the Cangre unit and the southern Rosario belt to the west. It is mostly overlain by the Quin ˜ones unit and in the east by the Bahia Honda area of the Cabaiguan* sequence. 7) Quin ˜ones unit. It is the highest unit of the sequence. In this report, it differs from the Pszczo´lkowski’s (1978) Quin ˜ones sequence in that it excludes the Guajaibo´n Formation (Vin ˜ as Group and Camaco Formation). It extends for 45 km (28 mi) east-northeast of San Juan de Sagua immediately south of the Cacarajı´cara* belt.

La Esperanza Belt The La Esperanza belt is considered the western equivalent of the Pizarras del Norte belt. It extends along the north coast of Pinar Del Rio from Manuel Sanguily to Mantua. Along the fault that separates it from the Pizarras del Norte subbelt, it is structurally both under and over the Pizarras del Norte subbelt. It should be noted that no Manacas Formation has been reported, separating it from the Pizarras del Norte belt. In the subsurface, it overlies the Vieja Member of the Manacas Formation. The structural and stratigraphic relationships with other belts are not entirely clear. There may be a relationship with the Cabaiguan* sequence.

Guajaibon–Sierra Azul Belt The Guajaibon–Sierra Azul belt, although geographically restricted, deserves the rank of belt because of its lithologic character. It consists of a sliver of platform carbonates between the northern Rosario belt and the Domingo* – Cabaiguan* sequence; it is the highest sedimentary thrust sheet.

Domingo* and Cabaiguan* Sequences Bahia Honda Area The Bahia Honda area is present only in northeastern Pinar Del Rio and is the continuation of the basic igneous-volcanic province of central Cuba. The Bahia Honda area is found north of the Cacarajı´cara belt, east of the La Esperanza belt. After the Pinar fault disappears, it merges with the eastern Los Palacios Basin. The Bahia Honda area is subdivided into two units: 1) Southern tectonic unit characterized by volcanics and volcaniclastics, with no ultrabasics, and dipping steeply northward under the northern tectonic unit. 2) Northern tectonic unit contains ultrabasics and extends from the coast to the fault that defines the southern limit of the ultrabasics. The tectonic style of the northern tectonic unit resembles that of the Habana and Matanzas provinces, and in the northern Domingo* and Cabaiguan* sequences of central Cuba, more than is present in most of Pinar Del Rio. Greater evidence of compression exists as indicated by the very steeply dipping and sheared Martin Mesa window of the northern Rosario belt, surrounded by nearly vertical beds of the Domingo* and Cabaiguan* sequences. The presence of reverse metamorphism in the Cangre belt is rather puzzling. It should indicate that the metamorphism occurred before the thrusting, but it has been dated as late as the Eocene, whereas the thrusting must have occurred from the Maastrichtian to the middle Eocene.

Los Palacios Basin The Los Palacios Basin is a sharp and deep feature probably underlain by the Cabaiguan* sequence. The prominent Pinar fault forms its northern boundary. Little is publicly known about the structures of this basin. To the north, much of the Tertiary and Upper Cretaceous section is exposed, with dips ranging from 30 to 708 south. The Pinar fault, which today is a very

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prominent feature, originated in the Eocene because the deposition of earlier beds (Anco´n and earlier formations) were apparently unaffected by the fault. Many authors describe it as a transcurrent fault, although the south side might be downthrown by more than 6000 ft (2000 m). This basin shows as a well-defined Bouguer gravity low and is apparently bounded to the south by a basic igneous-volcanic high, La Coloma, as indicated by a gravity and magnetic high (that terminates at the Pinar fault), and possibly the shallow Guane´ wells.

Isla de la Juventud Not much is known about the structures of the metamorphics of this island except that they consist of broad anticlines and synclines cut by faults. Although inverse metamorphism has been reported, there is no mention as to whether this phenomenon is related to superimposed folded thrust sheets as in Escambray. Of great significance is the presence of unmetamorphosed Cabaiguan* sequence volcanics in the northwest corner of the massif, as well as scattered outcrops of amphibolite and granitoids over the metamorphics. This suggests that, as in Escambray, the Cabaiguan* and Manicaragua-like sequences were thrusted over the metamorphic massif. In general, the metamorphism of the sediments is less intense than in the Escambray. It is of moderate pressure and high temperature.

Western Cuba Discussion No good generalized structural cross section of these units exists in the literature. Only Pszczo´lkowski (1994c) has presented drawings showing the tectonic styles. Some of these (sections A, D, E, and F) are shown in Figures 186–189 of this publication. Unfortunately, they are all in the eastern part of the Sierra de Guanguanico. No published map, at the proper scale, shows this area in sufficient detail to corroborate such cross sections. Although the details of structures can be extremely complex in thin-bedded formations such as the San Cayetano and the Santa Teresa formations, the overall structures are much broader and simpler in nature than in central Cuba. Figure 190 shows generalized and much simplified sections X and Y. All evidence indicates that the major movements were from south to north, with the upper thrust sheets being the ones originating farther to the south. The strongest evidence for such motion is, as in central Cuba, the total absence of basic igneous and volcanic detritus in any of the sedimentary belts until

the Maastrichtian. As in central Cuba, all the deformation seems to have occurred under water, initially through large submarine slides, as indicated by the very extensive development of the Vieja orogenic conglomerate or wildflysch. Unlike central Cuba, the deformation appears to have started in the Campanian (Moreno Formation) by uplift and initial slide of the Domingo* and Cabaiguan* sequences and culminated in the lower– middle Eocene, with the stack of thrusts moving northward. The epiorogenic Upper Cretaceous to middle Eocene basins (such as Los Palacios) were carried northward over the thrusts. From a structural point of view, the main difference between western Cuba and central Cuba is the absence of the thick Bahamas platform (and even perhaps the absence of a thick continental crust). As a result, the gravity slides of western Cuba slowed down through their own internal friction and eventually stopped toward the Gulf of Mexico without creating the intense compression and crush zone against the Bahamas that is evident in the northern part of central Cuba. Some of that deformation becomes visible toward the northeast in the Martin Mesa area. The Cangre belt is another example of reverse metamorphism. Here, like in the Escambray massif, the timing of the metamorphism suggests that it was caused, at least in part, by the overriding plate of basic igneous and volcanics. In addition, a similarity of structural style exists between western Cuba and the Escambray massif. Both areas show a broad anticlinorium of a stack of many thrust slices, contrasting with relatively narrow folds of only a few thrust sheets in central Cuba. Many authors have pointed out the stratigraphic similarity between the two areas, contrasting with the northern central Cuba section. This difference might be more apparent than real and might be caused by postdepositional events. For instance, the Lower Cretaceous Sabanilla Formation indicates that an appreciable Upper Jurassic shallow-water carbonate section was present south of the Las Villas* belt and eroded during the Lower Cretaceous. In addition, the well EPEP Pinar-1 discovered a thick, Upper Jurassic, shallow-water carbonate section very similar to the La Trocha* Group of central Cuba.

NORTHERN CUBA In northern Cuba, the exposures consist entirely of imbrications of Domingo* and Cabaiguan* sequences, and the surface structures are extremely complex; most

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FIGURE 186. Western Cuba cross section A. Modified from Pszczo´lkowski (1994c). See Figure 185 for location of cross section.

of the very numerous faults are nearly vertical and so are the strata in the core of the Habana-Matanzas anticline. Figure 132 shows the general structural style. The work by Gulf in that area was never completed, but Bro ¨ nnimann and Rigassi (1963) published an excellent article on the area incorporating much of Gulf’s work. The recent drilling along the coast found superimposed thrust sheets, with the lower one invariably consisting of the Las Villas* belt, the next one upward of the Cifuentes* belt, and finally, the uppermost sheet consisting of the Domingo* and Cabaiguan* sequences. No report of any well penetrating the Bahamas, Yaguajay, or Cayo Coco type of section exists. The structures are broken by many faults, and there is a definite break in strike between the rocks exposed

in the western Habana-Matanzas anticline (east –west trend) and those in the eastern end (west-northwest– east-southeast trend). Figure 191 shows a structural interpretation by Mossakovskiy and Albear (1978, 1979). This profile is based on surface geology and wells, but unfortunately, no indication of well names or locations exists in the article. The section shown is oriented north–south, between Havana and Cardenas. The structural style is definitely closer to that of central Cuba than to that of Pinar de Rio, but the authors show the Cabaiguan sequence under the Domingo sequence, suggesting the Bahia Honda belt, where the Felicidades is under the serpentine thrust. One important fact is that the sections present in northern Cuba prove the continuity of the Domingo

FIGURE 187. Western Cuba cross section D. Modified from Pszczo´lkowski (1994c). See Figure 185 for location of cross section.

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FIGURE 188. Western Cuba cross section E. Modified from Pszczo´lkowski (1994c). See Figure 185 for location of cross section.

and Cabaiguan sequences from the Bahia Honda area to the Santa Clara – Seibabo area. This gives strength to the concept that the Domingo and Cabaiguan sequences were thrust from the south over the Escambray massif.

EASTERN CUBA Eastern Cuba can be divided into three areas with remarkably different structural styles.

Northern Oriente As already mentioned, in northern Oriente, the Las Villas* to Cifuentes* belts equivalents are not present on the surface, and the Domingo* and Cabaiguan*

sequences are extremely deformed and in fault contact (Domingo fault) with the Gibara area carbonateplatform sediments. Figure 192 is a generalized geologic map, modified from Ando´ et al. (1996). It shows the extreme shearing and fragmentation of the basic igneous rocks with inclusions of exotic volcanic and sedimentary blocks.

Southeastern Oriente Southeastern Oriente shows much gentler structures, although the Mayari-Baracoa massif is an 800-m (2600-ft)-thick flat-lying nappe of ultrabasics overriding moderately deformed unmetamorphosed Cabaiguan* sequence in the Mayari area and metamorphosed Cabaiguan* sequence in the Purial massif. Figure 193

FIGURE 189. Western Cuba cross section F. Modified from Pszczo´lkowski (1994c). See Figure 185 for location of cross section.

Structural Geology / 339

FIGURE 190. Western Cuba cross sections X, Y. See Figure 185 for location of cross sections.

is an interpretation of the Mayari-Baracoa massif by Iturralde-Vinent (1994, personal communication). The reason for a sheet of unmetamorphosed ultrabasics to override metamorphosed and unmetamorphosed Cabaiguan* sequence volcanics is not entirely clear; the time of the thrusting appears to be between the late Maastrichtian and lower–middle Eocene. The thrusts are considered to have originated in the south, where the Cayman trough is now; however, the presence of very high Bouguer anomalies (+180 mG) under the Mayari-Baracoa massif suggests that the mantle is uncommonly high. This has been confirmed by crustal studies, but surprisingly, the geothermal gradient and the heat flow are very low (0.798F/100 ft, 39 mW/m2). The style of deformation is definitely more related to Pinar Del Rio than it is to northern Oriente

or central Cuba; there is no evidence of tightly crushed rocks. It must be emphasized that this is the only area in Cuba where the Cretaceous Cabaiguan sequence is found metamorphosed and structurally underlying the Domingo sequence. The metamorphism was high pressure and low temperature.

Southwestern Oriente Most of the outcrops in this area consist of the uplifted and faulted El Cobre Formation. In one locality south of the Sierra del Purial, near the coast, the El Cobre Formation is thrusted over the middle to upper Eocene San Luis and San Ignacio formations. Serpentine is present between the El Cobre and the underlying autochthonous sediments, and the direction of

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FIGURE 191. Northern Cuba cross section. Modified from Mossakovskiy and Albear (1978). See Figure 185 for location of cross section.

thrusting is north-northwestward. The serpentine was therefore involved in deformation as late as the upper Eocene. Perhaps this was related to the opening stages of the Cayman trough. As already mentioned, a seismic profile shot by the University of Texas across the Yucatan Basin continental slope, southwest of the Jardines de la Reina archipelago (Rosencrantz, 1990) (Figure 165), shows

a trench with the Yucatan Basin being subducted under the central Camaguey area and southwestern Oriente. This feature, which extends for more than 600 km (372 mi) from the Isla de la Juventud to the southwestern tip of Oriente, is very significant, but seen at only one location; it could represent a segment, now inactive, of the subduction responsible for the late Cuban volcanic arc. Pszczo´lkowski (2007,

FIGURE 192. Northern Oriente generalized geologic map. Modified from Ando´ et al. (1996).

Structural Geology / 341

FIGURE 193. Southern Cuba cross section: Mayari-Baracoa. See Figure 185 for location of cross section.

personal communication) queried a possible relation to the Cayman rise.

STRUCTURAL GEOLOGY DISCUSSION It is well established that the pre–upper Eocene structural style of Cuba consists of a stack of northwarddirected thrust sheets, nappes, or gravity slides, overlying a shallow-water Jurassic carbonate platform and evaporites. The southward and westward extent of the evaporites is unknown. In north central Cuba, the Platform carbonates have persisted until the present. The overlying sheets have an increasingly pelagic deep-water character toward the top. Toward the west, the entire section becomes clastic. Finally, above this stack is a massive thrust sheet with basic igneous (oceanic-rift crust) at the bottom, overlain by volcanics that show the increasing influence of a volcanic arc. The horizontality of the stack of thrusts is well preserved in eastern and

western Cuba, but in central Cuba, facing the Bahamas buttress, it appears to have been intensely compressed; there appears to be a zone of strong deformation separating the Bahamas-type platform carbonates to the north from the basic igneous volcanics to the south. In addition, this zone shows numerous vertical, possibly transcurrent, faults. Furthermore, three windows in the basic igneousvolcanic material show relatively low-grade metamorphics that are similar and equivalent in age to the sediments observed in the unmetamorphosed thrust plates. Geophysics suggests a connection between the Escambray massif and the Isla de la Juventud. There appears to be a segment of a northwarddirected subduction of the Yucatan Basin (or rise) under the Jardines de la Reina archipelago. The enigmatic La Trocha fault zone may be a deep-seated transcurrent fault or entirely restricted to the upper igneousvolcanic sheet. Figure 184 summarizes the above major tectonic elements.

6

Pardo, G., 2009, Hydrocarbons, in G. Pardo, The geology of Cuba: AAPG Studies in Geology Series, no. 58, p. 343 – 360.

Hydrocarbons KNOWN DISTRIBUTION AND TYPES OF HYDROCARBONS

(DSTs). Dry ammonia gas and minor amounts of methane were recovered in Shell Cayo Coco-2 DSTs. Nothing is known about the deep wells drilled by ICRM.

Evidence for the presence of hydrocarbons in Cuba is extremely widespread. Tar deposits, bituminous limestones, gas and oil seeps, and small producing fields are common throughout the island. Asphalt deposits were commercially mined at the turn of the century. The estimated daily production of the island was 34,000 BOPD for 1999 (Torres, 1999). However, to this date, despite the efforts by major western oil companies prior to the late 1950s (such as Chevron, Esso, Gulf, Shell, and Texaco), and those of many independents, plus the Eastern Block–Cuban cooperation since then, no major hydrocarbon accumulation has been found. The petroleum indications show a definite distribution pattern. The past and presently producing fields can be considered extensions of the seeps and therefore will be described under the same headings. For a general distribution of oil fields and petroleum indications, see Cuba, 1988. Known oil-field statistics are tabulated in Table 1.

Sagua La Chica* and Jatibonico* Belts Only a few tar indications in fractures are present in the Jatibonico* belt.

Las Villas* Belt Surface Indications Very few surface seeps are found in the outcrops of Las Villas* belt lithologies. However, these lithologies are reported to be productive in northern Cuba. Many fresh samples of these rocks collected from below the surface (core drill, fresh road cuts) show common oil-filled fractures and vugs, suggesting that the exposed limestones had contained oil at one time and lost it through weathering.

Subsurface Indications Two wells drilled in the Las Villas* belt had abundant hydrocarbon indications; Gulf Hicacos-1 and Gulf Guayabo-1. Hicacos-1 will be discussed under northern Cuba. Texaco Guayabo-1. It had common tar, heavy oil, and occasional gas to total depth at 10,010 ft (3052 m). The shows became more common below a thrust fault at 2910 ft (887 m), with Jaguita* overriding the Calabazar* Formation. The Calabazar* and Ramblazo* formations had no porosity or oil shows. The Capitolio* Formation had rare oil shows, and these were commonly associated with some dolomitization. The Upper Jurassic Caguaguas*, Jaguita*, and, possibly, Hoyo Colorado* formations had common dolomitization and abundant shows of 1–58 API tar. Some cores bled gas for several days after having been cut. A fractured limestone interval at 7628–7632 ft (2326–2327 m)

Central Cuba The occurrence of seeps will be described according to the geologic province or belts in which they are located. See Figure 194.

Yaguajay* and Coastal Area With the exception of a few tar indications (tar balls out of fractures in outcrops), no seeps are known from the Yaguajay* belt and coastal area. However, in Gulf Blanquizal-1, Shell Cayo Coco-2, Shell Manuy-1, and Texaco Mayajigua-1, all drilled in the coastal region or in the Yaguajay* belt, small traces of hydrocarbons were reported. These commonly consisted of tar in samples and small amounts of gas in drill-stem tests

Copyright n2009 by The American Association of Petroleum Geologists. DOI:10.1306/13141065St583328

343

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Table 1. Oil fields. Modified from Echevarria-Rodriguez et al. (1991) and G. Pardo, 1992, The Geology of Cuba Petroconsultants report.

Hydrocarbons / 345

FIGURE 194. Central Cuba: petroleum seeps, oil fields, and significant wells.

oozed 58 API tar every time drilling was stopped. On test, this interval produced 4 bbl of tar and a small amount of gas.

Placetas* and Cifuentes* Belt, Domingo* Sequence Most surface petroleum indications occur in the general area between the southern boundary of the Domingo* sequence and the southern boundary of the Las Villas* belt. This relationship extends from Habana to Oriente, although the complete succession of belts is present at the surface only in Las Villas and northwestern Camaguey (Wassall, 1956). In the subsurface, several accumulations occur in the upper part of the Cifuentes* and Placetas belts and below or within the base of the Domingo* sequence.

Surface Indications Within these belts, the seeps can be differentiated into two groups according to their character: 1) The first group consists of a zone of asphalt occurrences, more or less parallel and close to the Domingo* fault separating the Domingo* and Cabaiguan* sequences from (a) the Las Villas* belt to the southeast and (b) the Cifuentes* belt to

the northwest. The asphalt invariably fills fractures in the Placetas*, Cifuentes*, and Domingo* belt rocks or even occurs as dikes in basic igneous rock. These dikes can be quite large; the Jatibonico asphalt dike is several meters thick and more than 1 km (0.6 mi) long. Core drilling north of the town of Placetas (north of the above-mentioned fault zone) found abundant oil shows. In the neighborhood of the fault plane, the oil had gravities ranging from 15 to 358 API. In some cases, these shows came from boulders in Vega* or Rosas* Formation conglomerates, which displayed pressure release when broken. It therefore appears as if the original Domingo* thrust fault (presently a high-angle fault, or cut by a high-angle fault, with a left-lateral component) was at some time responsible for the migration and accumulation of hydrocarbons. The open, asphalt-filled fractures in its vicinity, as well as the vertical asphalt dike near Perea, are evidence that this process occurred under geostatic pressure conditions at great depth. 2) The second group of seeps is characterized by heavy to medium-gravity oil and gas; these occur in abundance over most of the Domingo* sequence, south of the Placetas* and Cifuentes*

346 / Pardo

belts. They are particularly well developed in a large area of serpentine outcrops (commonly containing abundant metamorphic exotics) near the town of Santa Clara. Some of the seeps are quite active and have been the basis for the development of most of the Cuban oil fields. A gas seep near Potrerillo produced an estimated 1440 ft3/day (40.8 m3/day). In addition, many water wells and core holes drilled in the area have had petroleum indications. One core hole (Sullivan Core Hole-8) was drilled by Gulf to 2343 ft (714 m) in 1955 in the center of the above-mentioned serpentine area, which was interpreted at the time to represent the crest of a large, anticlinally folded thrust sheet of ultrabasics. The hole was drilled for several reasons, but one of them was to find out if the very active seeps in the vicinity were an indication of a larger accumulation and/or a proximity to a different lithology at depth. A strong show of 398 API oil was encountered at 278 ft (85 m), and several barrels were produced. Unfortunately, no further shows were encountered to total depth. Brown & Root Laboratories, Inc. analyzed a sample of that oil sent to Tenneco. Their report, dated October 17, 1985, showed that the sample exhibited no obvious indication of biodegradation and the saturate fraction of the sample was very paraffinic. The percentage of naphtenes was not available but the report related that a visual examination of the gas chromatogram indicated the percentage was likely to be very low, suggesting an origin from a terrestrial or mixed terrestrial-marine source. Brown & Root Laboratories reported that normal alkenes were present in the sample out to approximately C35+, which further suggested a terrestrial influence. Because of the terrestrial aspects of the sample, the report concluded that a clastic rather than a carbonate source rock was favored. This conclusion is supported by an older Gulf Research & Development Co. analysis that reports 3.72% wax for the same oil. As will be seen later, this conclusion presents serious interpretation problems because the obvious source rocks are predominantly marine carbonates. Note that whereas the seeps in group 1 exhibit heavy and relatively immobile oils, those in group 2 produce much lighter petroleum and are quite active as though they were generated at depth by a source that is active today. In other words, the Domingo* sequence rocks appear to behave as a leaky cap over some accumulation (or hydrodynamic drive) at depth.

Oil Fields Jarahueca field. — This field, discovered in 1943, is located on the complexly faulted flank of the Jarahueca window and yielded 37 –408 API oil and some gas from basic igneous rocks (mostly from serpentine) and fractured limestone. However, the wells spudded in basic igneous rock commonly produce an oil of light-yellow color, in contrast to those spudded in the carbonates of the Cifuentes* and Placetas* belts, which produce a nearly black oil. No significant difference exists in API gravity. The meaning of this observation is not clear, but it seems to suggest that at this locality, the outcropping carbonate-igneous fault contact separates two types of oil in the subsurface. The fault must therefore act as a seal. The production behavior of the wells in this field suggests accumulation in fractured, low-permeability reservoirs; some wells have had initial production rates on the order of several hundred barrels of oil per day, dropping in a few days, and stabilizing for long periods of time at rates ranging from 1 to 20 BOPD. In view of the fact that most of the wells drilled prior to the late 1950s were shallow (less than 3500 ft [1100 m]), whether they reached a common reservoir or instead penetrated feeders to seeps is questionable. The field is reported to have produced a maximum of 960 BOPD in 1947. However, later, the production became very irregular, dropping between 160 and 18 BOPD from 1949 to 1964. In 1964, the last reporting date, the production was at 22 BOPD. Motembo field. — This field was discovered in 1881, but did not commercially produce until 1890. The maximum production was 465 BOPD in 1940 and has declined steadily since then. In 1964, the production was 6 BOPD. The production is entirely from serpentine and consists mostly of naphta (55– 658 API). Some gas as well as some heavier yellow and black oil are observed. The field is located near the contact between the Domingo* and Cifuentes* sequences, and the production characteristics are similar to those of Jarahueca. A southern extension of the field is called Vesubio.

Cabaiguan* Sequence Surface Indications This belt is impressively devoid of surface petroleum indications. Only a few petroleum occurrences are reported: one near Ranchuelo, in the Paleogene cover of the axis of the Seibabo syncline; and one in Habana Province, invariably in proximity to the Domingo* sequence rocks. This is somewhat of a puzzle

Hydrocarbons / 347

because the oil fields of the Central Depression are underlain by the Cabaiguan* sequence, and the volcanic section, although of general low permeability, is cut by many faults that should allow some seepage such as in the Jatibonico and Catalina fields.

Oil Fields Five fields exist, Catalina, Cristales, Jatibonico, Mamonal, and Reforma, which are known as the Central Depression fields. They occur in or near the western flank of the structural low believed to be associated with the La Trocha fault zone. As already mentioned, it is a thickening of the Paleocene to lower–middle Eocene flysch overlying the Cabaiguan* sequence. Upper Eocene and younger beds are not affected. Jatibonico field. — The Jatibonico field is located on the flank of the Central Depression and appears to be associated with seeps coming up the Arroyo Blanco group of faults. The oil seems to have migrated along the faults, as in Jarahueca, and accumulated in the volcanics under the Tertiary cover. The discovery well, General Corporation Echevarria-1, drilled in 1954, found 158 API oil at 1072 ft (327 m) in fractured volcanics of the Cabaiguan* belt under the Paleocene(?)– Eocene unconformity. Echevarria-1 was drilled to 8375 ft (2553 m) and remained in Cabaiguan* sequence volcanics to total depth and never encountered any carbonates or ultrabasics. The gross pay thickness is reported as 230 ft (70 m). EPEP Jatibonico-78, drilled less than 2 km (1.2 mi) to the southwest, penetrated the Cabaiguan* sequence at 1150 ft (350 m) and remained in the volcanics until 13,775 ft (4200 m), where it is reported to have penetrated pre-Jurassic(?) metamorphics to a total depth of 15,553 ft (4437 m). It is not known if these metamorphics are similar to those of the Escambray massif or of the Manicaragua belt. The maximum annualized production rate was 1230 BOPD in 1957. By 1963, the production had declined to 170 BOPD, and secondary recovery projects were initiated in 1964. Catalina field. — The Catalina field is located 13 km (8 mi) southwest of Jatibonico. The discovery well Drilling Catalina-1, drilled in 1956, found production of 32–358 API below 7102 ft (2165 m) in limy, fractured Catalina Shale. The total depth was 7157 ft (2181 m). Although this shale has been reported to be of Upper Cretaceous age, in this report, it is considered equivalent to the Paleocene Taguasco* and Fomento* formations. The situation appears to be similar to that of Jatibonico, with oil migrating up faults and accumulating at or near the Paleocene unconformity. The gross pay is reported to be 18 ft (5 m), and the

maximum annualized production was 26 BOPD in 1957. Cristales field. — Located some 25 km (15 mi) to the east of Jatibonico, the Cristales field appears to be of a similar in nature. The discovery well Cuban American Cristales-1A, drilled in 1956, found a gas accumulation below ±1800 ft (±550 m) in fractured vugular reef limestones of the Jiquimas* Formation (Cristales Limestone) of Maastrichtian age interbedded with volcanics. The depth of the productive interval averages 2600 ft (800 m). This section underlies the Paleocene unconformity. Oil shows were also found in the underlying volcanic sequence. This field was considered the first commercial gas discovery in Cuba. The initial tests gave 1 MMCFGD, and gas production began in 1971 and reached 2 MMCFGD in 1974. Oil was also being produced at the rate of 370 BOPD in 1964. No published information exists on Mamonal and Reforma fields, but they are believed to be of the same size as the Catalina field. It should be noted that oils from the Catalina and Cristales fields (Gurko et al., 1982) show great similarity to Jarahueca oils, including indication of meteoric loss of higher fractions, low asphaltenes, and a paraffinic composition of 28–69% (as in Gulf Sullivan-8, a suggestion of terrestrial influence). Numerous wells (most of them shallow) were drilled in the same La Trocha graben, farther southwest (in the vicinity of Sancti Spiritus), with no reports of oil indications.

Western Cuba: Pinar Del Rio The Vin ˜ales Group of limestones has long been known as a petroliferous section in the Rosario Mountains and in the Martin Mesa window. The San Diego de los Ban ˜os Basin, with its well-developed Tertiary section, has also attracted much attention in the past. Recently, the northwest coast of Pinar del Rio, in the Esperanza belt, has been the subject of an unsuccessful exploration and deep drilling program. See Figure 195.

Northern and Southern Rosario and La Esperanza Belts Surface Indications Most of the oil indications in Pinar del Rio are restricted to these belts. They consist mostly of heavyoil-filled fractures in the Jurassic and Lower Cretaceous carbonates. The Maastrichtian fragmental limestones commonly bleed oil, and asphalt veins

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FIGURE 195. Western Cuba: petroleum seeps, oil fields, and significant wells.

and deposits are common, especially when the Eocene and Cabaiguan* sequence equivalent overlies this belt like in Martin Mesa between the Rosario Mountains and Guanajay. An oil seep exists along the coast near Puerto la Esperanza.

Subsurface Indications Several wells have been drilled in the Rosario belt sediments, and most have had some shows and even some limited production. In general, the oil indications are similar to those found north of the Domingo* sequence and the Cifuentes* and Las Villas* belts of central and northern Cuba. The well EPEP Martin Mesa-1 has been reported as a discovery. This well on the north flank of the Martin Mesa window was drilled to 10,663 ft (3251 m). No published details exist as to the oil occurrence, but the well bottomed in the Neocomian, drilling through a thrust fault at ±5180 ft (±1580 m) that repeated the Aptian through Maastrichtian sequence. The section is an equivalent of the northern Rosario belt.

Sierra De Los Organos, Pizarras del Sur, and Cangre Belts Surface Indications No seeps are known from these belts; most of the outcrops consist of barren-looking San Cayetano Formation clastics, although some Jagua Formation and Vin ˜ales Group carbonates show bituminous material.

Subsurface Indications The well EPEP Pinar-1, drilled 4 km (2.4 mi) south of the town of Pons in the central Organos belt, found oil saturation in fractures associated with faulting, in the lower autochthonous carbonate sequence. This section, extending from 12,136 ft (3700 m) to a total depth at 17,056 ft (5200 m), consists of Upper Jurassic bank-type limestones.

Domingo* and Cabaiguan Sequences The Bahia Honda* belt ultrabasics are not well developed and do not have obvious seeps or production

Hydrocarbons / 349

FIGURE 196. Western Cuba: Isla de la Juventud gas seeps.

as in central and northern Cuba. However, there are oil indications and asphalt deposits in the volcanics of the Bahia Honda* belt between Cacarajicara and Bahia Honda and between Mariel and Cayajabos, where they are in proximity to or possibly overlie the Rosario belt. At least nine asphalt mines have been exploited there in the past. EPEP’s Mariel-1 and Mariel-2 were drilled to 10,171 and 10,312 ft (3101 and 3144 m), respectively, in Domingo* and Cabaiguan* sequence rocks (under the Miocene overlap) to a depth of ±7900 ft (±2400 m), where they encountered chaotic lower–middle Eocene conglomerates (La Vieja wildflysch = Rosas* Formation) to total depth. No seeps have been reported in the San Diego de los Ban ˜os Basin. Several relatively deep tests (such as ARCO Ban ˜os-1 and Ban ˜os-2, EPEP Candelaria-1, Rosario Taco Taco-1, and Rosario Soroa-1) were drilled south of the Pinar fault in its Cabaiguan*-like volcanics and overlying thick Tertiary sediments. Although methane and oil shows have been reported, there has not been a discovery in the basin.

Western Cuba: Isla De La Juventud A report of hard asphalt outcrop on the Isla de la Juventud proper, at Cerro Natividad, as well as on the keys north of the island was written (DeGolyer, 1918); this is difficult to believe and has not been subsequently confirmed. In addition, several gas seeps have been reported along the keys that extend eastward from the Isle of Pines from Punta del Este to Cayo Largo (Butticaz, 1952) (see Figure 196). Two of the gases were

analyzed and show 71 and 74% nitrogen, 12 and 24% methane, 16 and 0% hydrogen sulfide, and 1 and 2% carbon dioxide, respectively. These gas seeps are apparently quite active and build small underwater sediment cones. The origin of these gases is somewhat puzzling; the methane, hydrogen sulfide, and carbon dioxide could be either of recent organic origin, associated with hydrocarbon gases or of volcanic origin. However, little is known about the origin of high percentages of nitrogen, assuming that the chemical analyses are reliable. In other areas, it has been suggested that the nitrogen is produced by the breakdown of ammonia resulting from the decomposition of organic matter.

Northern Cuba As previously mentioned, the outcrops on this part of the island consist of a complex structural mixture of Domingo* and Cabaiguan* sequences. However, the Las Villas* and Cifuentes* belt lithologies have been recognized at depth in many of the wells (see Figure 197).

Surface Indications As mentioned in the Introduction, the Spanish colonists in 1508 knew of the presence of tar in Habana Bay. The petroleum seeps at the baths of Guanabacoa, now an eastern suburb of Habana, were also well known in colonial days. Seeps are common along the north coast of the island and at the type locality of the Universidad Formation, in the grounds of Habana

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FIGURE 197. Northern Cuba: petroleum seeps, oil fields, and significant wells.

University; this unit is impregnated with heavy oil. In Cardenas Bay, tar is coming to the surface of Holocene sediments along what appear to be fractures and forming underwater accumulations. These were mined at several localities from 1875 to the early 1900s. It should be mentioned that these tar seeps were reported as replenishing themselves. Cardenas Bay lies mostly over the northwest projection of the Cifuentes* belt and its contact with the Domingo* sequence.

Subsurface Indications Many water wells drilled in this general area have had oil and gas indications. This is also true of the many shallow holes drilled near seeps. Gulf Hicacos-1 was drilled in northeastern Cardenas Bay in 1949. It penetrated the Las Villas* belt at 2290 ft (698 m) to total depth at 5045 ft (1538 m) below an Eocene to Holocene cover and was cut by at least one major fault at 4030 ft (1229 m) that brings lower– middle Eocene under the Upper Jurassic Caguaguas*

Formation. The section immediately below the upper Eocene marls consists of fractured Cretaceous limestone, saturated with tar for 539 ft (164 m). The tar sometimes forms a high percentage of the rock, strongly suggesting an Eocene seep. The entire Jurassic – Lower Cretaceous section contains numerous heavyoil indications. Since 1960, there has been much drilling, with some of the wells deeper than 12,000 ft (3700 m). The detailed results are unknown, but led to the discoveries of Varadero and Boca de Jaruco fields.

Oil Fields Several oil fields are located between La Habana and Cardenas Bay. They are named, from west to east, Bacuranao-Cruz Verde, Santa Maria del Mar, GuanaboBrı´sas, Pen ˜as Altas, Boca de Jaruco, and Via Blanca fields in Habana Province, and Yumurı´, Camarioca, Cantel, Varadero, Guasimas, Marbella, and Chapelin fields in Matanzas Province. Many of these are old inactive

Hydrocarbons / 351

(±670 m). The accumulation is reported to be in highly folded sediments under an unconformity. The maximum production was 98 BOPD in 1958, and in 1964, it was producing 3 BOPD. A pilot steam injection program was started in 1966, but there is no information about the results.

fields, but Boca de Jaruco and Varadero have been recently developed and are reported to contribute the great bulk of today’s Cuban production. From the sparse literature, they appear to be similar in general character and regional structural position to those of Jarahueca and Motembo; they are located on or near the northern outcrops of the Domingo* and Cabaiguan* sequences, in proximity to and/or over the Cifuentes* and Las Villas* belt rocks. Published information on these fields is somewhat vague and very limited, with no maps (well location, reservoirs, etc.) and no production statistics. The stratigraphic nomenclature does not follow the terminology of the other Cuban publications. The sections are invariably described as stacks of strongly folded paraautochthonous, allochthonous miogeosynclinal to allochthonous eugeosynclinal material separated by south-dipping, low-angle thrust faults. However, as described in Chapter 2 of this publication, it is possible to give a reliable limited translation of these terms to the nomenclature followed in this report.

This field was discovered in 1969 and is drilled largely offshore. The production consists of 178 API oil with high sulfur content. The structure is very complex and consists of a stack of two major thrust sheets. In the south of the field, downdip from the crest of the structure, the section has been described under Drilling, Cifuentes Belt, Chapter 2 of this publication. An autochthonous section has not been penetrated, and oil is being produced from fractures in the sections under the two major thrusts. The top of production for each zone is
1500 ft (
450 m) and
2700 ft (
825 m), respectively. The reported initial recoverable reserves are given as 6 MMBO.

Bacuranao-Cruz Verde

Varadero

This is the oldest of the northern Cuba fields. Bacuranao was discovered in 1914. It produces 25–288 API oil from fractured serpentine (Domingo* sequence) from 200 to 800 ft (60 to 250 m). The gross pay is 300 ft (90 m). The deepest well was drilled to 7665 ft (2336 m) and encountered conglomerates and sandstones below the serpentine. The field began production in 1916 and was abandoned in the 1940s. Cruz Verde started producing in 1955, and Bacuranao went back on stream in the early 1960s. The maximum production was 146 BOPD in 1958 and was 74 BOPD in 1964.

It is the largest field discovered so far; it was discovered in 1972. The production consists of 178 API oil with high sulfur content. H2S has been reported. The structure is complex and consists of a folded major thrust sheet with at least one imbrication. The section downdip from the crest of the structure has been described under Drilling, Cifuentes Belt, Chapter 2 of this publication. The bulk of the production comes from the structure under the major thrust fault, which consists of a fractured anticline in the Las Villas* belt section. The top of the pay is at
2130 ft (
650 m), and the oil – water contact is at
3400 ft (
1050 m). An autochthonous section has not been penetrated, and the reported initial recoverable reserves are given as 30 MMBO. Not much published data exist on the Pen ˜as Altas, Camarioca, Cantel, Chapelin, Guasimas, Marbella, and Yumuri fields. Some information indicates the following: (1) The section and accumulation in Pen ˜as Altas are very similar to those of Boca de Jaruco; (2) Chapelin and Marbella have a section similar to that of Varadero and also produce from the Las Villas* belt rocks; and (3) Camarioca, Cantel, Guasimas, and Yumuri also consist of a stack of thrusts and produce from the Cifuentes* and/or Domingo* – Cabaiguan* sequence rocks. For a generalized cross section of the fields in the Varadero vicinity, see profile II0 across area 3 insert in Cuba, 1988.

Santa Maria Del Mar The discovery well Ted Jone Jones Bess-1, drilled in 1955, is reported to have encountered 15–288 API oil at 2200 ft (670 m) in fractured serpentine (Domingo* sequence) and vugular dolomite. The serpentine is overlain by 1065 ft (325 m) of Maastrichtian volcanics and clastics possibly belonging to the Via Blanca and older formations (Cabaiguan* sequence). These, in turn, are overlain by 350 ft (105 m) of lower–middle Eocene and younger Tertiary. This field produced a maximum of 78 BOPD in 1957 and was producing 14 BOPD in 1964.

Guanabo-Brisas The discovery well Ted Jone Jones Juanita-1, completed in 1956, encountered 8–118 API oil in tuffaceous sandstones and volcanic flow rocks at ±2200 ft

Boca de Jaruco-Via Blanca

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Eastern Cuba There are some confirmed oil indications in Oriente. According to DeGolyer (1918), the Farola asphalt seep, occurring in serpentine, was mined in the past. This occurrence cannot be located, but Cuba (1988) shows two seeps in serpentine south and near Puerto Padre. However, over the years, several wells (such as Transcub Embarcadero-1, Benedum Eugenia-23/1, Transcub Manzanillo-1, and Transcub Rio Tana-1) have been drilled in and on the flanks of the Cauto Basin without any encouragement.

SOURCE ROCKS In Cuba, abundant sediments would be considered classical petroleum sources. However, there is no assurance that the oil presently found on or near the surface originated entirely from these sources. The maturation and migration history might not have been favorable for the formation of petroleum deposits at the proper time. It is unfortunate that at the time of the original Gulf studies, hydrocarbon analytical techniques and the present concepts of the origin, maturation, and migration of oil were either nonexistent or in their infancy. Today, much better quantitative studies could be done along the lines of source beds, maturation, correlation of potential sources with produced petroleum, and between different petroleum types. Although many of the fundamental problems of the origin of oil remain to be solved, the geological complexities of Cuba render the task of understanding the relationships between source and possible accumulation highly speculative. A problem in assembling this study is the absence of published data based on modern geochemical techniques. It should be pointed out that the association of oil and gas seeps with ultrabasic rocks is not unique to Cuba. Almost every major Mesozoic to Tertiary ophiolitic area in the world has petroleum indications: Greece, Turkey (both known since antiquity), the Zagros Mountains in Iran, New Zealand, and the Franciscan complex in California are among the better known ones. In every case, the explanation given for the petroleum occurrence is that the ophiolite was thrusted over, or intruded into, petroleum-generating sediments. Although this is a likely explanation, one should keep an open mind to the possibility of a yet-unknown process. Szatmari (1989) proposes a Fisher-Tropsch oil-generation process (hightemperature hydrogenation of carbon monoxide from

carbonates) during the obduction of serpentine over carbonates. As seen in the preceding section, there appear to be two kinds of oil in Cuba. The oils associated with the basic igneous and the volcanics are medium to high gravity, low viscosity, paraffinic, and with low to no sulfur content. The oils associated with the carbonates are low gravity and high viscosity and have a high sulfur content; hydrogen sulfide is occasionally present.

Obvious Possible Sources The following Upper Jurassic and Cretaceous units appear to be good candidates for petroleum source rocks:

Central Cuba With some exceptions, central Cuba does not exhibit sediments with an apparent high (present-day) organic content in outcrop. The colors are generally tan to gray, and as already mentioned, tar and oil indications in outcrops here are not as spectacular as in Pinar del Rio. However, this could be the result of a deeper weathering of central Cuba, as well as less welldeveloped Jurassic exposures.

Las Villas* Belt The exposed Jurassic Hoyo Colorado*, Jaguita*, and Caguaguas* formations consist of massive limestones, laminated limestones with oolitic intervals, and medium-grained dolomites. They indicate an alternation of shallow-water carbonate bank deposits with an oxidizing environment and deeper water pelagic deposits. They correlate with and are similar to the Pinar del Rio, San Vicente, and El Americano members of the Guasasa Formation. The Berriasian to Barremian Capitolio* Formation is a gray, massive, biomicritic limestone, with thin wavy laminations and numerous secondary chert nodules. It consists entirely of nannoconids, calpionellids, and radiolaria skeletons with common aptychi and was deposited in deep waters. The gray color, the preservation of the nannoplankton, and the lack of bottom-dwelling organisms suggest anoxic conditions. This unit is similar and equivalent to the Sumidero Member of the Artemisa Formation. The Aptian to Cenomanian is represented by the Penton*, Calabazar*, and Mata* formations that consist of alternations of thin-bedded, and at times laminated, limestones and primary radiolarian cherts. These units are essentially of pelagic origin. The only exceptions are thin layers of bioclastic turbidites

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originating from the shallow carbonate banks. The Calabazar* Formation is characterized by black cherts and limestones that are dark gray when fresh and weather to chalky white, indicating abundant organic, bituminous matter. These units correlate in part with the Pons Formation.

Placetas* and Cifuentes* Belt The Berriasian to Barremian is represented by the Ronda* Formation. This unit has similar textures and compositions, and it is therefore similar, in environment of deposition, to the Capitolio* Formation of the Las Villas* belt. The amount of argillaceous material and organic content increases toward the southernmost facies, as indicated by the change from brown to black color. The Aptian to Cenomanian is represented by sediments that range from the above described Calabazar* and Mata* formations of the Las Villas* belt through the Carmita* Formation assemblage of limestones, cherts, thin-bedded shales, and fine-grained sandstones of the Placetas* belt to the Santa Teresa* Formation of the Cifuentes* belt, consisting entirely of thin, even-bedded, varicolored cherts (radiolarian) and shales. This entire group of formations is of pelagic origin and may have had source potential not too unlike the Monterrey of California. This, however, is difficult to assess at present.

Cabaiguan* Sequence The only unit that appears to have source potential is the Gomez* Formation, of Cenomanian age, which, in the exposure of its best development on the north flank of the Seibabo syncline, consists of thinbedded black and brown pelagic limestones interbedded with dark-gray shales. Although the thickness at this locality, 500 ft (150 m), is adequate to generate hydrocarbons, the regional distribution of this facies is not known.

Western Cuba The rocks outcropping in this province display some very spectacular examples of what today is considered a classical source rock. They are found mostly in the Jagua Formation and the Vin ˜ales Group, particularly in the Rosario belt. Black bituminous pelagic limestones, black shales containing ammonite-bearing concretions that release oil when broken, as well as limestones that give a strong sulfurous and bituminous odor when freshly broken are present. The units that are considered good candidates for a petroleum source are as follows.

Sierra de los Organos Belt The Jagua Vieja Member of the Jagua Formation, of upper Oxfordian age, consists of black laminated shales with ammonite-bearing limestone concretions; the concretions contain oil (commonly inside the ammonite chambers). The Guasasa Formation, of Kimmeridgian to Cenomanian age, contains several black, micritic, pelagic, limestone members: the San Vicente and El Americano members. The gray to black micritic limestones and cherts of the Pons Formation, of Valanginian to Turonian age, also have the classical characteristics of organicrich sediments deposited under fairly deep and anoxic water conditions.

Northern and Southern Rosario Belts The Francisco Formation is a correlative of and lithologically similar to the laminated and petroliferous Jagua Vieja Formation described above. The Kimmeridgian to Valanginian Artemisa Formation, with its well-bedded micritic limestones and cherts, is equivalent to the lower Guasasa and is an even more favorable source. It appears to have been deposited under even deeper, pelagic, and anoxic conditions and is characterized by a strong petroliferous odor and the presence of asphalt. The Buenavista Group and the Santa Teresa, Pinalilla, and Moreno formations, of Barremian to Maastrichtian age, containing abundant radiolarian cherts and, like the Las Villas Santa Teresa Formation, could have contributed hydrocarbons.

Northern Cuba Here, the Las Villas* and Placetas* or Cifuentes* belt lithologies of central Cuba are present and are associated with the current production. These rocks, which act as reservoirs in several fields, are also believed to be the source of petroleum, particularly the Upper Jurassic ones.

Oriente With the exception of isolated blocks of pelagic carbonates included in the ultrabasics of the Silla de Gibara area, no outcrops of any of the type of rocks described above exist.

Speculative Sources In addition to the several potential petroleum source rocks mentioned above, some other possible, although speculative, sources should be discussed.

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Central Cuba Coastal Area: Jaguajay* and Jatibonico* Belts The Jurassic and possibly older rocks underlying the shallow-water bank carbonates exposed or drilled in this area are essentially unknown. The deepest wells in a normal stratigraphic section or the most complete exposures of the Yaguajay* belt show less than 14,000 ft (4300 m) of section that is less than half the estimated depth to basement. The Gulf Blanquizal III-1, Texaco Mayajigua-1, and Shell Punta Alegre-1A wells bottomed in the Lower Cretaceous or questionable Upper Jurassic. Only in Shell Cayo Coco-2, the Yaguajay*, and the Jatibonico* belts was the Jurassic identified. Some of the ICRM deep wells drilled along the coast are reported to have penetrated the Jurassic, but no detailed information on them exists. However, the outcrops at Punta Alegre and the Kewanee Tina-1, Kewanee Tina-2, and Kewanee Collazo-1 wells show a section dominated by Portlandian evaporites tectonically out of stratigraphic sequence. These, as well as the section in Gulf-Chevron Cay Sal-1 and Tenneco Doubloon Saxon-1, suggest a thick Lower Cretaceous and Jurassic carbonate and evaporite section. The question, of course, is whether the carbonates associated with the evaporites could have been good petroleum generators. No direct answer to this question exists; the Sunniland production of southern Florida, as well as the strong Sunniland oil shows in some wells off Key West, must have originated from limestones within this type of section. Another problem is whether the San Cayetano Formation clastics are present under and/or partially equivalent to the Cayo Coco* Formation. The presence of these two formations in close proximity is supported by the fact that the San Adrian gypsum diapirs, in northern Matanzas, contain abundant exotics of sandstones and shales identical with those that make up the San Cayetano Formation in Pinar del Rio. The San Cayetano Formation has not been traditionally considered a favorable source, but this will be discussed under the section on Western Cuba in this chapter. The carbonate muds and bioclastic platform sediments of the Lower Cretaceous upper Cayo Coco* and Guillermo* formations could conceivably have been sources of petroleum under the proper temperature conditions for the reasons given above, although they are not prime candidates; this is where kerogen studies of the available samples of some of the wells are needed. The Aptian –Turonian is represented by the thinbedded limestones, shales, marls, and black cherts with abundant pelagic organisms of the Guillermo*,

Romano*, and Contrabando* formations. These pelagic units appear to be limited to the Cayo Coco – Punta Alegre area. They could either represent deeper water tongues separating shallow-water carbonate banks (Upper Cretaceous Old Bahamas Channel) or be limited by Upper Cretaceous structural conditions. It should be noted that there is a regional discontinuity between the Lower Cretaceous massive carbonates and the Upper Cretaceous pelagic marls in parts of the Bahamas and Florida. Their value as a source is unknown, but it is not considered to be very high.

Las Villas* Belt The base of the section is not exposed. The dolomitic Hoyo Colorado* Formation, of Tithonian age, could be underlain by a Cayo Coco* facies and even by the San Cayetano Formation. This, as previously mentioned, is definitely suggested by the exotics in the San Adrian gypsum diapirs. If the evaporites and/or the shales formed a de´collement surface at the base of the Las Villas* belt, it could be riding over the carbonate bank facies and its speculative source rocks. A major unknown, from a source standpoint, are the once widespread and thick (over 3000 ft [900 m] exposed in the Jatibonico area) flysch deposits of lower– middle Eocene age of the Vega* and Rosas* formations. These terrigenous deposits, with limited present-day exposures, had a very active source of sediments from the south. They were deposited in deep waters and were rapidly buried under the advancing, thick, orogenic front. They served as a gliding surface for the Domingo* thrust and the Cifuentes*, Placetas*, and Las Villas* belt imbrications. Organic matter is not obvious in outcrops, where the Vega* Formation is invariably deeply weathered because of its content of feldspars and mafics. In cores, however, oil can be seen seeping out of freshly cut boulders. If these sediments were a source, it could explain the suggested terrestrial clastic origin of the oil sample from Gulf Sullivan-8. It could also explain the abundance of oil indications in the Domingo* sequence and along the fault separating it from the Las Villas* belt where the Vega* Formation is always found crushed along the fault plane. Most importantly, it would explain the difference between the oils of Domingo* and Cabaiguan* sequences and those associated with the carbonates. The Vega* Formation is also the only known synorogenic sedimentary unit structurally below the Domingo* sequence, with a large-enough thickness and clay content and low-enough permeability to be able to maintain geostatic pressures for some appreciable period of time. This is considered essential to generate

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the necessary hydrodynamic gradient for the migration of hydrocarbons. It is possible that the serpentines could have had a similar behavior. Geostatic pressure is certainly indicated by the asphalt dikes in the Domingo* sequence.

Domingo* Sequence As previously mentioned, in the general Santa Clara area, there are outcrops of Maastrichtian, noncalcareous, shales of the Miguel* Formation that were deposited under pelagic conditions, which appear to structurally underlie the Domingo* sequence. Nothing is known about the original thickness and distribution of these deposits, which could have generated hydrocarbons under the right circumstances.

Escambray Massif It should be mentioned that the low-grade metamorphics in the core of the mountains contain quartzites interbedded with gray graphitic mica schists: the Naranjo Group that ranges from the Lower Jurassic to the Oxfordian. These are overlain by dark-gray to black limestones with sulfurous odor: the Sauco and Mayari formations that range from the lower Tithonian to Lower Cretaceous. In the rim of the mountains, there are some higher grade metamorphics consisting of black marbles and schists with graphite of the Collantes Formation of equivalent age. These units, which are similar to and correlate with parts of the Pinar del Rio section, at some pre-Upper Cretaceous time, could have contributed hydrocarbons prior to metamorphism.

Western Cuba The San Cayetano Formation has not been traditionally considered a source rock. This is caused by the abundance of coarser clastics, to some variable degree of metamorphism, to its usual white to reddish color in the outcrops, and to the absence of seeps or other oil indications. However, the formation is very thick (estimates of up to 15,000 ft [4600 m] have been made) and consists of a well-bedded alternation of sandstones, siltstones, and shales, commonly barren of organisms; it is of black to dark-gray color when fresh. Plant remains and carbonaceous material are present. It appears to be a typical deltaic sequence, and one could expect associated prodelta muds. This entire section certainly shows many petroleum source characteristics that would also be compatible with the suggested origin of the oil in Gulf Sullivan-8. The San Cayetano Formation equivalents certainly covered a large area in addition to Pinar del Rio. They outcrop as exotics in the San Adrian diapirs and, ex-

hibiting various degrees of metamorphism, in the Isla de la Juventud (Can ˜ ada Formation) and in the Escambray massif (Naranjo Formation) in Las Villas Province. It would be of interest to ascertain if some of the exotic metamorphic blocks found in the serpentine in the vicinity of the town of Santa Clara could be related to the San Cayetano. In addition, near the top of the section and equivalent to part of the Jagua Formation are beds of black fossiliferous limestones, with a strong sulfurous odor when broken, which appear to have been deposited in an anoxic environment.

MATURATION If one accepts all the units described in the previous section as potential sources, the best that can be done at present is to try to make reasonable assumptions regarding the maturation and possible migration of hydrocarbons.

Temperature The first point to consider is that, in the Escambray massif, the age of the youngest metamorphosed sediments, the Loma Quivican Formation, is believed to be pre-Campanian Upper Cretaceous. If the internal thrusting of the massif is prior to the metamorphism and the apparent inverse metamorphism is caused by the overriding by the Domingo* –Cabaiguan* thrust plate, as was initially proposed by Milla´n and Somin (1981), the metamorphism must be Maastrichtian or later. If the thrusting within the massif is postmetamorphism and the apparent inverse metamorphism is caused by the stacking of several plates of increasing metamorphic grade, then the metamorphism must be related to the post-Cenomanian Upper Cretaceous volcanic arc. Regardless of whether one considers that the Domingo* and Cabaiguan* sequences rode northward over the Escambray massif or that the Domingo* and Cabaiguan* sequences were extruded by the closing of the back-arc between the North American continental margin and the Escambray massif, the metamorphism should have occurred when the Escambray rocks were much farther to the south or west of their present position. Thus, in either case, the entire succession from Lower Jurassic through the Cretaceous and from the southern coast of Cuba to the Bahamas should have had a normal continental margin thermal regime up until the early Eocene. It should be noted that neither the carbonate belts nor the Cabaiguan* and Domingo* sequences show any indication of thermal metamorphism. The same is true in Pinar del Rio. The

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metamorphism in the Cangre belt is interpreted as a separate thrust sheet adjacent to the Pinar fault. The information available on temperature comes from three sources: 1) Kewanee Collazo-1 and Gulf Hicacos-1. In bottomhole temperature measurements, they show a very low geothermal gradient of 0.458F/100 ft (0.828C/100 m). 2) General Corporation Echevarria-1. A temperature log from the uncased well in the Cabaiguan* belt shows a somewhat higher, but still low, gradient of 0.838F/100 ft (1.518C/100 m). 3) Published heat-flow measurements from 35 boreholes by Cermak et al. (1984, 1991) (see Chapter 5, this publication). The given temperature gradients are as follows: Coastal area: Punta Alegre: 0.378F/100 ft (0.688C/ 100 m) Organos– Pinar del Rio: 0.758F/100 ft (1.378C/ 100 m) Domingo* or Cabaiguan* –north coast: 1.168F/ 100 ft (2.118C/100 m) Domingo* or Cabaiguan* – Cardenas Bay: 1.668F/ 100 ft (3.038C/100 m) Cabaiguan* – Jatibonico oil field: 2.148F/100 ft (3.908C/100 m) Cabaiguan*–Central Depression–western Camaguey: 1.348F/100 ft (2.438C/100 m) Cabaiguan* – central Camaguey: 0.838F/100 ft (1.518C/100 m) Because the data from 1 and 2 are taken from logs and are uncorrected, they probably tend to underestimate the true gradient. The data from 3 are believed to be much more representative because the boreholes stabilized over a period of years before the measurements were made. However, the measurements taken in the continental margin show very low values, 0.45–0.758F/100 ft, whereas those taken in the Domingo* – Cabaiguan* sequence are appreciably higher, 0.83 – 2.148F/100 ft.

A Model A greatly oversimplified picture of the structural evolution and distribution of lithologic units was considered. The model depicts the following conditions: 1) That the San Cayetano and equivalent Cayo Coco* and Punta Alegre* formations, as well as older un-

known facies, represent the filling of a subsiding rift, with sedimentation more or less keeping pace with subsidence. 2) That there was a continuous regional subsidence from Berriasian to the end of the Cretaceous with, to the north, the Yaguajay* and Coastal Province carbonate sedimentation keeping pace with the subsidence, whereas the belts to the south did not and received only pelagic sedimentation in waters on the order of some 13,000 ft (4000 m) deep. 3) That the thrusting started in early Tertiary, producing deep-water flysch deposits, the Vega* Formation, which were overridden in middle Eocene by the Domingo* –Cabaiguan* sequences thrust sheet, the whole process terminating before the upper Eocene. 4) That only relatively minor later activity occurred because no upper Eocene and later detrital deposits are well developed in Cuba (they could be present offshore). Consequently, the pre– upper Eocene and later erosion in central Cuba and Pinar del Rio were ignored. Using surface temperatures of 258C at sea level and 58C in deep water, paleodepth and paleotemperature diagrams for two hypothetical locations were prepared: at a north location on the carbonate bank and a south location inside the thrust belt. Two oilgeneration modeling techniques, the Lopatin and Arrhenius methods of calculating the time-temperature indices (TTI), were used for each location (Wapples, 1980; Wood, 1988). The Arrhenius technique gives somewhat more optimistic results than the Lopatin. The following results were obtained: 1) If the entire continental margin had a geothermal gradient of 18F/100 ft (1.8248C/100 m), then, at the northern location, only the Jurassic and the lowermost part of the Cretaceous would have been subjected to a high-enough temperature during a long-enough period of time to have generated petroleum; however, neither technique indicates that Cretaceous rocks reached the peak of oil generation. Moreover, the temperature at the southern location would have been affected by increased water depth and by the thrusting. Only the Lower Jurassic (if it exists) would have been under the right conditions until the lower Eocene and the entire Jurassic, Lower Cretaceous, and possibly the Upper Cretaceous, and the lower part of the Eocene flysch might have generated oil afterward. In other words, this suggests that oil

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generation from the obvious sources might have been the direct result of the overthrusting. 2) If the southern Bahamas–northeastern Cuba had a gradient of 0.58F/100 ft (0.9128C/100 m), only the Lower Jurassic (if it exists) would have been under favorable conditions at the north location. In conclusion, these calculations, obviously very approximate, suggest that, unless (1) there is an unknown source older than anything observed and (2) the geothermal gradient was in the vicinity of 18F/100 ft (1.8248C/100 m), the Cuban carbonate platform province had little chance to generate much oil. Tenneco’s Doubloon Saxon-1, with a total depth at 21,740 ft (6628 m), should furnish critical information when the data are released. However, they also suggest that the oil observed in Cuba at present is the result of the orogenic process that provided the necessary overburden for the maturation of the organic matter in the obvious possible and also speculative source sediments. It should also be noted that because of the low geothermal gradient (18F/100 ft; 1.8248C/100 m) the maximum depth of wet-gas preservation could be on the order of 23,000– 26,000 ft (7000 – 8000 m).

MIGRATION AND ACCUMULATION This is unquestionably the aspect of Cuban petroleum geology that is most critical and most difficult to resolve. In most geosynclinal petroliferous basins, the deeper part of the basin, with a high percentage of argillaceous material and a greater thickness of sediments, is considered the source of petroleum as well as the source of high fluid pressures that drives the hydrocarbons toward the stable margins of the basin where they accumulate in traps (hydrodynamic sinks). Therefore, the possible sources of fluid, the potential aquifers or reservoirs, and finally, the seals will be discussed.

Source of Fluids All sediments are a potential source of fluids; quartz sands and most carbonates have an original water content on the order of 45%, and the clays and pelagic oozes on the order of 70%, which can be reduced to a few percent by normal compaction. However, only the clays will be able to generate overpressures because of their low permeability and swelling pressure; all the other sediments will generate overpressure only if they are enclosed within low-permeability sediments such as clays or evaporites (this is a complex

and dynamic process). In Cuba, thick and extensive argillaceous sediments are known only in the Jurassic San Cayetano Formation (and related metamorphics), the Cretaceous Cabaiguan* sequence volcanics, and the lower–middle Eocene Vega* Formation flysch and equivalents. The Cabaiguan* sequence volcanics contain abundant argillaceous material, but are unlikely to have been involved in the petroleum-generation process; only the San Cayetano and the Vega* formations could have been an important factor. The San Cayetano Formation is the only unit suggesting a deltaic sequence certainly capable of generating overpressures. One can safely assume that, at least until the end of the Cretaceous, it had a fairly normal compaction gradient, similar to that found in many present-day deltas. Whether the San Cayetano Formation and equivalents could have developed and maintained overpressures for any length of time would have entirely depended on the shale percentage distribution, and no data on this subject are available. Furthermore, if overpressures existed, the direction of fluid flow during the Jurassic and Cretaceous would have depended on the paleogeographic reconstruction of the sand and shale facies.

Central and Northern Cuba In the Escambray massif, where the metamorphosed equivalents of the San Cayetano are present, if one assumes that the direction of internal thrusting was from south to north, then the La Llamagua sands were to the north, and the Herradura shales were to the south prior to the thrusting. This indicates that the direction of compaction fluid flow during the Jurassic and Lower Cretaceous was from south to north. During the orogeny in uppermost Cretaceous to middle Eocene, the direction of fluid flow must have been controlled by the advancing thrusts and, therefore, must have been from south to north over much of central Cuba. Farther to the north, in the Cayo Coco–Punta Alegre area of the coastal province, the abundant evaporites must have channeled the migration of fluids southward toward the edge of the banks. The geometry of the possible transition from the Punta Alegre* (and/ or lower Cayo Coco) Formation to the San Adrian (and/or San Cayetano) Formation, and its effect on fluid-flow patterns, is totally unknown. However, no evaporites are present in the Yaguajay* and Jatibonico* belts nor in the Gulf Blanquizal-1. Collapse breccias in the dolomite are common in the wells and outcrops, indicating the solution of Lower Cretaceous and possibly older evaporites. However,

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these two belts were near the bank edge, and few evaporites might have extended this far from the center of the basin. This would suggest that along the bank edge, there might have been a zone of cross-formational fluid flow of unknown age, but possibly as old or older than the early Tertiary. This zone might have prevented the hydrocarbons, generated during and/or prior to the orogeny, from reaching the carbonate platform province and, therefore, the Bahamas foreland. The noncalcareous shales of the Maastrichtian Miguel* Formation could certainly have been a source of fluid, but unfortunately, they are known only in a few isolated outcrops. The lower –middle Eocene Vega* Formation must have been a source of fluids with near-geostatic pressures acting, therefore, as an effective hydrodynamic seal for fluid flow from older strata. This is caused not only by its clay content and high shale percentage, but by its rapid deposition and burial under the advancing Domingo* – Cabaiguan* sequence thrust sheets. As mentioned previously, the presence of asphalt dikes or veins is a definite indication that geostatic pressures existed at one time at the base of the Domingo* sequence and in the underlying sedimentary belts. It is unfortunate that, because of the structural complications, the outcrops of the Vega* Formation are so poor that it is impossible to map the lithologies of this unit on a regional scale. In northern Cuba, the carbonate bank facies has not been recognized and probably did not extend west of the Cardenas Bay, so the only movement of fluids there must have been directed northward toward the Gulf of Mexico.

Western Cuba In Pinar del Rio, the San Cayetano facies distribution strongly suggests that during the Jurassic, and possibly later, a south to southwestward direction of compaction fluid flow existed. The direction of fluid movement is more difficult to estimate during the orogeny because both northward and southward thrusting have been recognized. Although chaotic, flysch and wildflysch, orogenic detritus is widespread, no thick shales such as the Vega* Formation have been recognized in Pinar del Rio.

AQUIFERS AND RESERVOIRS Clastics Generally, in Cuba, good reservoirs of this type are very few.

Central and Northern Cuba Here, the Jobosi* and Constancia* formations could be considered potential reservoirs if well developed. They seem to cover a large area. However, where they have been observed, they are thin and have a dense calcareous matrix, although they have been reported as reservoirs in some north Cuba fields. It is not known if production is from intergranular or fracture porosity and permeability. Several volcanic-derived sandstones in the Cabaiguan* belt sequence exist, but they are quartz poor with a high percentage of feldspars and clays that reduce the permeability and effective porosity. The lower Eocene clastics of the Upper Vega* and Rosas* formations are believed not to have reservoir potential for the same reasons. Nothing is known of the possibilities of a San Cayetano Formation equivalent in this area; if present, its porosity might be greatly reduced by the additional overburden of the thrust sheets that could be on the order of more than 13,000 ft (4000 m).

Western Cuba In Pinar del Rio, the San Cayetano Formation consists of a thick section of quartz sandstone interbedded with shales. The sandstone percentage can be very high, but it is impossible, because of structural complications, to determine the possible location of favorable sand/shale ratios. Although the sandstones in outcrops appear porous, they are invariably hard and well lithified when fresh. An additional problem is the variable degree of metamorphism. La Esperanza Formation also contains abundant sandstones, but very little is publicly known about it. The Tertiary Diego Formation outcropping south of the Pinar fault has numerous porous sands interbedded with shales that, under the right circumstances, could be good reservoirs.

Carbonates These form the reservoirs in the largest fields (Varadero and Boca de Jaruco) and are the most likely potential reservoirs.

Central and Northern Cuba In the Cayo Coco –Punta Alegre area and the Yaguajay* and Jatibonico* belts, the secondary dolomites found throughout the Lower Cretaceous and Upper Jurassic section are capable of being good reservoirs with adequate intercrystalline porosity and permeability. Platform limestones, if fractured near fault zones or other structures, are also possible reservoir beds. Vugular porosity and solution cavities are

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occasionally found but are difficult to predict. Reefs are a definite possibility, but so far, they have not been observed. In the Las Villas* and Placetas* belts, the medium-grained dolomites of the Tithonian Hoyo Colorado* Formation appear to have enough porosity and permeability to be reservoirs. In addition, the associated massive shallow-water limestones, as well as those of the overlying Jaguita* Formation, could form good reservoirs if fractured. The same is true of the Lower Cretaceous pelagic limestones of the Capitolio* and Ronda* formations.

Western Cuba In the Mogotes and Rosario belts, the massive limestones and dolomites of the Guasasa and Artemisa formations could be good reservoirs if fractured. Similar potential reservoirs are the several orogenic carbonate conglomerates found in every tectonic belt and the Cretaceous massive miliolid limestones of the Guajaibon Formation (Vin ˜as* Group).

Other Rocks Several other types of rocks form present-day reservoirs, such as fractured serpentine, gabbros, volcanics, and conglomerates. Whether these can produce sizable reservoirs with commercial flow rates is not known but unlikely.

Sal-1 and Tenneco Doubloon Saxon-1 wells. The dense limestones of this province are probably too fractured to be a barrier to fluid motion. Farther south, in the Yaguajay* to Cifuentes* belts, the known Jurassic and Cretaceous section is devoid of evaporites; however, there is the possibility that the autochthonous section with evaporites extends farther south and west under these belts as suggested by the presence of the San Adrian diapirs. Jurassic evaporites could be the de´collement surface under the Yaguajay* and Las Villas* belt. If this was the case, autochthonous reservoirs could be sealed by the evaporites under the allochthonous belts.

Western Cuba No evaporite beds have been definitely reported from Pinar del Rio. None of the logs of the Pinar del Rio wells, published in the 1985 geologic map (Cuba, 1985a), show evaporites. However, dolomite and anhydrite are reported by Kuznetsov et al. (1985) in the Puerto Esperanza wells, but not shown in the well logs. In the EPEP Pinar-1 well, Lopez-Rivera et al. (1987) report anhydrite, in nodules and fracture fillings, within the shallow-water Jurassic carbonates. The amount of anhydrite increases toward the total depth of the well at 17,058 ft (5200 m).

Argillaceous Sediments POTENTIAL SEALS As previously mentioned, a characteristic of the sediments exposed in Cuba is the lack of well-developed shales or other potential seals. Evaporites are found in the subsurface and outcrop only as diapirs; whether they can form continuous seals remains to be seen. In all areas, it should be emphasized that the thrust faults themselves, with their Vega* (or similar) Formation material smeared along the fault plane, might form the best seals available. All surface and drilling evidence points to it. This type of seal apparently traps much of the present production. In view of the complexity of the fault geometry, whether it can be adequate for major accumulations remains to be seen.

Evaporites North and Central Cuba The evaporites of the coastal province are capable of being effective seals when present. They occur in the Cayo Coco–Punta Alegre area and could be extensive elsewhere in the northeastern coastal region. They are present in the Bahamas’ Gulf-Chevron Cay

Central and Northern Cuba Except for the highly deformed Santa Teresa* Formation, the carbonate belts are essentially devoid of argillaceous material. The only known possibilities of argillaceous seals would be the Upper Cretaceous noncalcareous shales of the Miguel* Formation and the shales of the lower–middle Eocene Vega* Formation. Both units probably underlie the Domingo* thrust and are caught in the fault planes of the many imbrications. In the northern Cuban oil fields, the seals over the existing production consist of Tertiary shales and graywackes, ultrabasics, and volcanics (olistostromes) caught along folded, faulted, and imbricated lowangle faults. This indicates that the faults behave as seals. However, it is the author’s opinion that the complexity of the geometry of the observed faults has prevented the discovery of major accumulations. Perhaps there are some less complicated faults at depth or in unexplored areas. As mentioned before, the fact that most of the active seeps are located in the ultrabasics of the Domingo* sequence suggests that these rocks, because of the fracturing, act more like a low-permeability reservoir

360 / Pardo

than a cap. However, the volcanics of the Cabaiguan* sequence do seem to act as a definite seal but they outcrop mostly in the trough of a large, faulted, sharp syncline.

Western Cuba Here, the exposed Jurassic and Cretaceous nonvolcanic section shows a higher argillaceous content than that of central and northern Cuba. The San Cayetano, Jagua, and parts of the Artemisa, Polier, and Lucas formations have variable amounts of shale interbeds. In addition, some uppermost Cretaceous and Paleocene units like the Anco´n, Buenavista, and Sierra Azul formations have well-developed shale beds. Un-

fortunately, their reported stratigraphic position is not too clear, and their relationship with older rocks, as suggested by the presence of volcanic outcrops within their described sections, could be of a structural nature. In the Los Organos belt, a detrital section of lower to middle Eocene age, the Pica Pica Formation, contains shales. This unit is fairly thin but suggests the Vega* Formation of central Cuba and could similarly be much more extensive and involved in the thrusting, making the thrusts themselves effective seals. The volcanics of the San Diego de los Ban ˜ os belt, south of the Pinar fault, could provide some seals, but so far, despite all the drilling, no shows have been reported. In the same area, the Tertiary Diego Formation contains numerous shale beds.