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Home , Geology of North America, Lesser Antilles

Caribbean Geology: An Introduction ©1994 The Authors U.W.I. Publishers' Association, Kingston

CHAPTER 1

Geologic Provinces of the

GRENVILLE DRAPER1, TREVOR A. JACKSON2 and STEPHEN K. DONOVAN2

1Department of Geology, Florida International University, Miami, Florida 33199, U.SA. 2Department of Geology, University of the , Mona, Kingston 7,

INTRODUCTION South American . The western boundary com- prises and the Isthmus of , and the THE CARIBBEAN is a geologically complex region that eastern limits are defined by the Lesser archipelago. displays a variety of plate boundary interactions including Within these boundaries there are several deeper water in the Lesser Antilles and Central America, ; the Yucatan Basin, the Cayman Trough, the Colom- transcurrent (strike-slip) motions on the northern and southern bian Basin, the Venezuelan Basin and the Basin. boundaries, and sea floor spreading in the Cayman These are separated by several more or less linear ridges and Trough. The central Caribbean is a lithospheric plate con- rises; by the Cayman Ridge, the Nicaraguan Rise, the Beata sisting mainly of an anomalously thick, oceanic plateau Ridge and the Aves Ridge, respectively. The physiographic situated between two major continental regions and therein units correspond in part to the different crustal provinces lies its geological importance. Classic studies of the Alps, that make up the Caribbean and in part to the active tectonic and Appalachians have documented the effects elements that make up the present . of major continent-continent collisions. The Caribbean pro- vides the opportunity to study the nature of the geological evolution of arcs, and the tectonic interaction between PRESENT PLATE CONFIGURATION anomalously thick oceanic crust and continental crust. The purpose of this chapter is to introduce the physiog- The location and nature of plate boundaries in the Carib- raphy and geology of the Caribbean region. Although de- bean, as elsewhere, are determined by the location of earth- tailed analysis of tectonostratigraphic has been quake hypocentres; by use of the sense of slip from first published previously11, in the present account we attempt to motion studies on seismogenic faults; from detailed outline the features of the major geologic provinces that bathymetric, magnetic and seismic profiling studies of ma- make up the Caribbean and to provide a framework for the rine areas; and from detailed mapping of recent, on-land more detailed descriptions which follow in this volume. structures if the plate boundary happens to be exposed onshore. These studies show that the boundaries of the Carib- PHYSIOGRAPHIC PROVINCES bean Plate (Fig. 1.1 A), as defined by the distribution of earthquake epicentres53, run approximately from Guate- The Caribbean region is comprised of several major marine mala along the trend of the Cayman Trough, through His- and terrestrial physiographic and geologic provinces, the paniola and , south through the Lesser Antilles, geographic relationships of which are illustrated in Figure and along the northern continental margin 1.1. Geographically and bathymetrically, the (although this boundary is poorly defined between is bound to the north by the Gulf of , the Yucatan and the Meridional ) and the west coast of Central Platform, the Florida-Bahamas Platform and the Puerto America. First motion solutions7,28 indicate left-lateral Rico Trench, and to the south by the northern part of the strike slip at the northern boundary and right-lateral strike

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Geologic Provinces of the Caribbean Region slip at the southern boundary, indicating that these are left important geophysical features of the Caribbean Sea floor. lateral and right lateral transform boundaries, respectively. The B" horizon marks the boundary between igneous sills Thrust solutions, typical of the upper part of convergent and overlying Upper Turonian to Coniacian sedimentary plate boundaries, are found in both the western and eastern strata. This reflector has been traced from the lower Nicara- margins of the plate. The depth of the hypocentres and their guan Rise eastwards through the Venezuelan Basin . The position relative to volcanoes indicates Wadati- A" horizon is considered to mark the boundary between Benioff Zones dipping eastward beneath Central America Lower to Middle oozes and chalks, and underlying and westward beneath the Lesser Antilles. Detailed marine Upper chertiferous limestones. This reflector and terrestrial studies have considerably refined this general extends from the lower Nicaraguan Rise in the west to the picture, although there are considerable differences of opin- Grenada Basin in the east. Borehole data from Deep Sea ion about the details of the present direction and rate of Drilling Project Leg 15 indicates that the B" horizon consists movement of the Caribbean Plate relative to its neighbours. of the uppermost layers of a large oceanic basalt plateau with a The Caribbean Plate is moving eastwards with respect to crustal thickness of between 15 and 20 km. This plateau both North and South America31 at a rate of about 1 to 2 was produced by a significant oceanic flood basalt event that cm yr-1. The northern and southern boundaries of the plate occurred during the late Cretaceous14 (Donnelly, Chapter 3, are thus transform fault systems dominated by left-lateral herein). and right-lateral strike-slip motions, respectively. Unlike

transform fault systems in oceanic crust, where the move- Colombian Basin ment is accommodated in single, discrete fault zones, the The Colombian Basin is defined by the Hess Escarp- movements in the Caribbean are distributed on several ac- ment to the north, and the continental margin of Panama and tive fault zones to produce broad, active seismic zones about to the south. The Colombian Plain, extending to 200 km wide. As it is difficult to pinpoint the precise plate depths of 4000 to 4400 m, is the largest abyssal plain in the boundary, the north and south Caribbean Plate boundaries 8,28 Caribbean region and is located in the northeast part of the are best characterised as plate boundary zones . basin. This plain extends north to , south to the The Motagua, Polochic and other fault zones form Magdelana Fan and east to the southern corner of the Beata the eastern extension of the Northern Caribbean Plate Ridge22. Both the Magdelana and the Panama-Costa Rica Boundary Zone in Central America. A left lateral step- Fans introduce significant quantities of into the over in the boundary between the Caribbean and North basin along its southern and western edges. The has resulted in a crustal-scale pull-apart basin, Panama and South Caribbean Deformed Belts are under - the Cayman Trough, in which a 100 km long spreading thrust margins to this basin. ridge segment has been produced. This ridge is bounded by two extensive transform faults, the Swan Island Transform Fault and the Oriente (previously Bartlett) Beata Ridge Transform Fault. East of , left lateral displacement The Beata Ridge is a structural high that extends south- may be accomodated on several fault zones in northern west from Cape Beata, Hispaniola, for about 400 km. The Hispaniola and offshore. Left lateral displacement has also ridge has a relief of about 2000 m and is comprised of a been documented south of the Cayman Trough in Jamaica series of north-south trending subsidiary ridges which be- 8,29,30 come less pronounced towards the south, where it converges and southern Hispaniola , and forms the southern 11,26 boundary of a microplate 44. on the South Caribbean Deformed Belt . Initial uplift of the The eastward movement of the Caribbean Plate has ridge occurred during the late Cretaceous and coincided with structural disturbances that affected the northern Colombian resulted in subduction of the crust under 23 the eastern margin of the Caribbean, producing the Lesser Basin and the Hess Escarpment . Subsequent tectonic Antilles island arc system. Eastward motions of the Pacific events have led to the tilting of the ridge and to and Cocos Plates with respect to the Caribbean and North deformation along its southern margin.

Amer ica are equally rapid, which has resulted in subduction of these plates beneath the western margin of Venezuelan Basin the Caribbean, that is, under Central America. The Venezuelan Basin is the deepest and largest of the Caribbean basins. The interior of the basin includes less than 200 m of relief, having been 'smoothed' by the accumulated GEOLOGIC PROVINCES —CARIBBEAN SEA . The basin is deepest at its northern (Muertos Trough) and southern (Venezuelan Plain) boundaries, Seismic reflectors A”and B” where it converges with the North and South Caribbean Persistent seismic reflector horizons A" and B" are Deformed Belts, respectively11. Most of the sediment in the

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G. DRAPER, T.A. JACKSON and S.K. DONOVAN

Figure 1.1. (A) Map of the Caribbean region showing the relative positions of plates, physiographic regions and major (redrawnafter Jackson24). Direction of subduction shown by solid triangles. (B) Geologic provinces of the Caribbean region, as defined in the present chapter (simplified after Case and Dengo10; Case et al.12). Key: AP=Anegada Passage; AR=Aves Ridge; BeR=Beata Ridge; BP=Bahamas Platform; BR- Ridge and Lesser Antilles Deformed Belt; C=Cuba; C A=Colombian Andes; CB=Chortis Block; ChB=Choco Block; CO=Cuban Orogenic Belt; CoB=Colombian Basin; CT=Cayman Trough; CtB=Chorotega Block; EPFZ=E1 Pilar Fault Zone; GA=; GAOB=Greater Antilles Orogenic Belt; GB=Grenada Basin; GM=; H=Hispaniola (+); J=Jamaica; LA=Lesser Antilles; MPFZ=Motagua-Polochic Fault Zone; NP=Nazca Plate; NPD=North Panama Deformed Belt; NR=Nicaraguan Rise; OTF=Oriente Transform Fault; PR=Puerto Rico; SCD=South Caribbean Deformed Belt; SITF=Swan Island Transform Fault; VB=Venezuelan Basin; VBo=Venezuelan Borderland; YB=Yucatan/Maya Block; YBa=Yucatan Basin.

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Geologic Provinces of the Caribbean Region basin was derived from the eastern margin, marked by the Chorotega and Choco Blocks Aves Apron that extends westwards from the Aves Ridge. Geographically, this province comprises Costa Rica, Panama and northwestern Colombia. The Choco Block, west of and overridden by the Cordillera Occidental of the GEOLOGIC PROVINCES—CENTRAL AMERICA Colombian Andes, comprises a sequence of uplifted Upper Cretaceous to Paleogene oceanic crust and magmatic arc Yucatan/Maya Block rocks. The Choco Block abuts deep forearc basins to the The Yucatan, or Maya, Block is located on the North west containing up to 10,000 m of pelagic, turbiditic and American Plate and is separated from the Chortis Block by marginal marine sediments and sedimentary rocks 11. East- the Motagua-Polochic fault system. The (pre-Carbonifer- ern Panama (Choco Block) is a raised block with a ous) basement of the Yucatan Block is exposed in its southern of late Cretaceous or older oceanic crust, topped by seismic extremity, near the Motagua suture, and occurs in various reflector BM (see above), and overlain by Upper Cretaceous wells in the subsurface. It is composed of schists, marbles, pelagic sedimentary rocks9. Panama became attached to quartzites and granitoids of unknown age. These rocks are South America and nuclear Central America during the late unconformably overlain by Upper Carboniferous to Permian or Pliocene13. sedimentary and volcanic rocks 15. The Chorotega Block is essentially the northern exten- The Palaeozoic sedimentary rocks are unconformably sion of the Choco and comprises a series of belts overlain by a 'red bed' sequence (Todos Santos parallel to the Pacific coast developed by subduction of the Group) and thick, Cretaceous dolomitic limestones. In the Cocos Plate and subsequent of terranes on the southern part of the block, Upper Cretaceous to Tertiary western seaboard. Reversal and repetition of the forearc olistostromes and immature of the Sepur Group ridge and basin occur in the east of Panama1 . The overlying overlie the rocks. The Chicxulub Crater in Middle America volcanic province is a northwest-southeast the middle of the Yucatan carbonate platform is the trending belt in western Panama consisting of Miocene to probable candidate for the Cretaceous/Tertiary boundary Holocene calc-alkaline volcanics and related deposits. This impact crater21. volcanism is related to subduction at the Middle America Trench11. Chortis Block The northern boundary of the Chortis Block on the GEOLOGIC PROVINCES—NORTHERN Caribbean Plate is defined by the Motagua-Polochic fault CARIBBEAN system (at present, an active strike-slip fault zone, but this was previously a suture zone formed by the late Cretaceous Gulf of Mexico collision of the Chortis and Yucatan Blocks), which is also The northern margin of the GuIf of Mexico is underlain the boundary between the Caribbean and North America by a broad zone of stretched and thinned continental crust, Plates. The southwestern boundary is the Middle America as is the southern part (see Maya/Yucatan Block, above). Trench, which separates the block from the Cocos Plate. The central part of the GuIf of Mexico is underlain by However, the southern and eastern boundaries are less well Upper Jurassic to Lower Cretaceous oceanic crust. This defined. structure is the result of the rifting of the Maya/Yucatan The basement of the Chortis Block consists of pre- Block from North America38,39,46, which resulted from (probably Palaeozoic) metamorphic rocks and approximately northwest-southeast continental extension associated Mesozoic plutons which outcrop in the northern that took place from the to the late middle and central parts of the block. The Mesozoic sequence is Jurassic. This was followed by sea floor spreading until the generally similar to that of the southern part of the Yucatan earliest Cretaceous. Block to the north, but less well documented15. A Jurassic to The continental basement on the northern and southern Lower Cretaceous 'red bed' sequence (correlated with the margins of the Gulf of Mexico is overlain by Triassic and Todos Santos Group of the Yucatan Block) overlies the Jurassic 'red beds' and Jurassic evaporites (Louann and basement rocks. These are in turn overlain by massive provinces, respectively). Uppermost Jurassic Lower Cretaceous limestones. A major Upper Cretaceous sedimentary rocks comprise shallow-water limestones on 'red bed' sequence (Valle de Angeles Formation) sits on the margins of the Gulf, with deep-water carbonate facies in these limestones. A major unconformity separates the the central regions. A similar pattern persisted through the Mesozoic sequence from extensive volcanic de- Cretaceous and produced thick carbonate sequences. These posits. limestones are overlain in the western and central Gulf of Mexico by terrigenous clastic sedimentary rocks derived as

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G. DRAPER, T. A. JACKSON and S.K. DONOVAN a result of late Cretaceous orogenic uplift in western North deformation occurred earlier in the west. The islands consist America and Mexico. of a Jurassic oceanic basement (exposed in central His- paniola and southwest Puerto Rico) overlain by Lower Florida and Bahamas platforms Cretaceous (Aptian-Albian or possibly older) to Paleogene The Florida and Bahamas carbonate platforms (here island arc deposits (volcanic and epiclastic deposits with taken to include the regions underlying the Turks and Caicos associated immature clastic and carbonate sedimentary Islands) lie to the north of both the Cuban Orogenic Belt and rocks). Although there is some evidence for Cretaceous the Hispaniola segment of the Greater Antilles Orogenic deformation events16,17,33,34, which may have a similar age Belt The Florida and Bahamas platforms consist of a con- to those in Cuba, the major tectonic deformation in these tinuous sequence of Middle Jurassic to Recent carbonate islands was usually later. Late Cretaceous to early Paleogene sedimentary rocks which are over 6,000 to 7,000 m thick in deformation was associated with an oblique collision of the 48 southern Florida and over 10,000 m thick in . Greater Antilles arc with the Florida-Bahamas platform, but The accumulation of these limestones resulted from the which did not appear to produce the extensive thrusting subsidence accompanying the rifting that formed the Atlan- otherwise seen in Cuba. In contrast, in Jamaica (see Nicara- tic Ocean and Gulf of Mexico. In Florida, the northward guan Rise, below), the early Paleogene was a period of thinning carbonate accumulations unconformably overlie crustal extension and resulted in deposition of rift facies Triassic to Lower Jurassic arkoses and volcaniclastic sedi- sediments. From the post- to the present, the mentary rocks, which in turn rest on Palaeozoic basement. islands have experienced another major orogenic phase due The situation is similar in the western Bahamas, under the to sinistral transpression caused by the eastward motion of Great Bahama Bank, but east of New Providence island the the Caribbean Plate relative to North America. These 48 basement consists of Jurassic oceanic crust . transcurrent movements produced a series of strike-slip related, clastic -filled basins. In adjacent areas, moderate Cuban Orogenic Belt subsidence coupled with eustatic sea level changes pro- Western and central Cuba form a major orogenic belt, duced carbonate build-ups. characterized by northwardly-directed thrusting of Creta- ceous island arc volcanic rocks, with associated oceanic Nicaraguan Rise crust, over a sequence of to slope, Jurassic The Nicaraguan Rise extends northeastwards from to Lower Cretaceous limestones and mature clastic sedi- and in Central America to Jamaica and mentary rocks. It was previously thought that this orogenic southern Haiti2. It is bounded on the northern edge by the belt resulted from the collision of an island arc with the Cayman Trough and along the southern margin by the Florida-Bahama continental margin in the late Cretaceous northeast-southwest trending Hess Escarpment. The Nica- 20 to early Tertiary . The Campanian ages of olistostromes raguan Rise is a broad, topographically complex feature of deposited at the front of advancing thrust sheets, and Cam- shallow to intermediate depth (0-3000 m) along which there panian metamorphism of continental margin sedimentary is an upper (less than 1200 m water depth) and lower (greater rocks in southern Cuba indicate that the Cuban orogeny than 1200 m water depth) rise22. The lower Nicaraguan Rise comprised a middle Cretaceous, and an early Cenozoic, is separated from the upper part by the Pedro Bank escarp- 41 orogenic events (Draper and Barros, chapter 4, herein). ment or Pedro Bank Fracture Zone11 and from the Colom- Cuba is the only region in the Greater Antilles where bian Basin by the Hess Escarpment. The lower, or Precambrian age rocks occur. Grenville age (approximately southern11, Nicaraguan Rise is comprised of a series of 1,000 Ma) metamorphic rocks outcrop in Las Villas prov- faults, troughs and volcanoes. This is particularly evident 42,50 ince in north central Cuba . These rocks may represent an along the northeast and southwest margins, where there are exposed fragment of the basement underlying the sedi- prominent rifts (the Morant and San Andres Troughs, re- mentary rocks of the continetal margin. spectively). Closely associated with these troughs is a series Southeastern Cuba contains rocks formed in a Paleo- of seamounts and islands formed from late Cenozoic vol- cene island arc which has a geological history distinct from canic rocks57. western and central Cuba. Lower rise strata vary in thickness between 500 m and 1000 m, whereas the upper rise, which is mainly a carbonate Greater Antilles Orogenic Belt platform, is underlain by over 5000 m of strata11. Emergent The Greater Antilles orogenic belt comprises His- portions of the upper rise include Jamaica, as well as several paniola, Puerto Rico, the and southeastern carbonate banks to the south of the island. The known Cuba. This province differs from that of the orogenic belt of stratigraphy of the upper rise, determined from various western and central Cuba in style of deformation, although sources 23,36,37 (Robinson, chapter 6, herein), suggests that

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Geologic Provinces of the Caribbean Region

a basement of Upper Jurassic(?) to Lower Cretaceous oce- nated by the Cayman Ridge, a subsided volcanic arc devel- anic oust (with continental oust in the west) is overlain by oped on pre-Cenozoic oceanic(?) crust. In the east this predominatly stratified Upper Cretaceous volcanic rocks crustal block dips northeast beneath the Cuban margin. and Tertiary limestones. Geophysical data show the maxi- 1,2 mum thickness of the rise to be about 22 km . GEOLOGIC PROVINCES —EASTERN CARIBBEAN Cayman Trough The Cayman Trough is approximately 1600 km in Lesser Antilles length, 120 km in width and 5 km deep. It comprises a floor The Lesser Antilles volcanic arc is comprised of a series of thin oceanic crust (less than 7 km) partly overlain by a of islands stretching from Grenada in the south to the 37 veneer of younger sediments . The trough extends west- Anegada Passage in the north, a distance of 850 km. It is wards from the Windward Passage to the Gulf of Honduras separated from the Barbados Ridge in the south by the and separates the Cayman Ridge from the Nicaraguan Rise. Trough, a forearc basin, and from the Aves Ridge The Cayman Ridge may be a fragment of the Nicaraguan by the Grenada Basin. Rise which became separated by the opening of the Cayman The area has been described as a double arc -32 Trough. system" In the southern half of the chain the two arcs The approximately east-west trending Oriente and are superimposed on one another to form the islands of Swan Island Transform Faults are connected by the north- Grenada, the , St. Vincent, St. Lucia and south trending Mid-Cayman Rise. The last is the site of . These islands contain volcanic and east-west seafloor spreading and hence the trough is essen- sedimentary rocks that range in age from the middle 30 tially a crustal-scale pull-apart basin . Therefore, the Cay- Eocene to the Holocene35. North of Martinique the arc man Trough is an important tectonic feature, as the rate of bifurcates into an older outer ridge and a younger inner spreading on the Mid-Cayman Rise must be equal to the ridge (the Limestone Caribees, inactive for the past 28 relative rate of movement of the Caribbean, with respect to Myr, and Volcanic Caribees, respectively). The Volcanic the . Caribees have a history of late Tertiary and Quaternary The timing of the opening of the Cayman Trough volcanism (Wadge, chapter 9, herein). 27 remains unresolved. MacDonald and Holcombe con- Most of the volcanic activity in the Lesser Antilles is tended that the Cayman Trough is no older than Miocene, subaerial, as recorded by the eruptions in St Kitts, Guade- 45 whereas Rosencrantz and Sclater recognised magnetic loupe, Martinique, St. Lucia and St. Vincent during historic anomalies that trace the opening back to the mid Eocene. times49. Sea-going surveys6 have shown that the only active This also has implications regarding spreading rates. Mac - submarine in the region is Kick-'em-Jenny, which 27 Donald and Holcombe considered that spreading rates is located just north of Grenada in the Grenadines. were 2 cm yr-1 for 0 to 2.4 Ma and 4 cm yr"1 for 2.4 to 6 Ma, whereas Rosencrantz and Sclater postulated rates of 1.5 Barbados Ridge -1 -1 cm yr for 0 to 30 Ma and 3 cm yr before then. Recent The Barbados Ridge is a forearc ridge that emerges 18,44 GLORIA and SeaMARC II sidescan mapping has re- above sea level at Barbados, an island capped with Pleisto- vealed a more complex spreading history punctuated by cene limestones and underlain by deformed Tertiary sedi- intervals of rise jumping. mentary rocks (Speed, Chapter 10, herein). The ridge is divided into an inner (=arcward) zone and an outer (=ocean- Yucatan Basin ward) region51, and forms part of the western margin of the The Yucatan Basin is bounded to the south by the Lesser Antilles accretionary prism25, which is over 300 km Cayman Ridge, to the west by the Yucatan Peninsula of wide. Mexico, and to the north by western and central Cuba The inner zone of the Barbados Ridge consists of rocks 43 Rosencrantz divided the basin and its borderlands into and structures similar to those of the Paleogene basal com- nine domains based on seismic reflection studies and surface plex of Barbados, including turbidites, olistostromes and topography. These domains occur on three distinct types or volcaniclastic sedimentary rocks. The thickness of this low blocks of crust. In the west, the eastern shelf of the Yucatan density rock sequence may be as much as 20 km. Rocks of Peninsula is characterized by northnortheast-southsouth- similar compos ition occur in the outer (eastern) region of west trending extensional faults and grabens. This Yucatan the Barbados Ridge, but here consist of recently accreted, borderland is flanked by a rectangular deep that occupies the fault-bounded packets51. western third of the basin. The floor of the eastern two thirds Accretion may have commenced in the Eocene during of the basin is topographically heterogeneous, but is domi- the early growth of the Lesser Antilles island arc. The

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G. DRAPER, T.A. JACKSON and S.K. DONOVAN

differing structures of both the inner and outer zones may Plate. The emergent parts of the belt comprise the Caribbean reflect two discrete accretionary events. Speed51 suggested Mountain System of northern and the southern that the inner zone developed above a lithospheric slab Antllean island chain of , and Curaçao. The descending to the northwest, while the outer zone was central part of this island chain is separated from the main- formed above a slab descending to the west. From the land by the 2000 m deep Bonaire basin. The Curaçao Ridge commencement of accretion (about 50 Ma) to the present is a bathymetric high located north of the An- the Barbados Ridge has been rising as a result of the growth, tilles and separated from it by the Los Roques Trough. This thickening and backthrusting of the accretionary com- area represents a zone of intense deformation and accretion, 25,54 plex . and is an eastward extension of the South Caribbean De- formed Belt that contains about 10 km of Paleogene(?) and 11,23,26 Aves Ridge Neogene pelagic and turbiditic deposits . The La Or- The Aves Ridge is located 200 km west of the Lesser chila Basin, a northwest-southeast trending graben, sepa- Antilles arc and extends in a north-south direction for about rates the Venezuelan Antillean islands of Los Aves, Los 500 km. It is a plateau between 50 and 150 km in width that Roques and La Qrchila from La Blanquilla, Los Hermanos, includes several steep-sided, north-south trending pedestals, Margarita, Los Frailes and Los Testigos to the east. one of which rises above sea level to form Aves Island56. The South Caribbean Island Chain comprises islands of The rocks underlying the ridge comprise a basement of the Netherlands and Venezuelan Antilles which extend from Cretaceous to Paleocene basalts, andesites and granites, that Los Monjes in the west, eastward to Los Testigos. These are overlain by about 1500 m of pelagic and shallow-water islands are located on an east-west structural high and ap- 3 Tertiary sedimentary rocks 11. The crustal character and pear to be genetically related to one another (Jackson and composition of the rocks of the Aves Ridge suggest that the Robinson, Chapter 14, herein). The Netherlands and Vene- area represents the site of an extinct magmatic arc5,23,40,52. zuelan Antilles consist of weakly metamorphosed Creta- ceous volcanic and sedimentary rocks which were intruded Grenada Basin by late Cretaceous granitoid bodies of various sizes, and are The Grenada Basin separates the southern portions of capped by late Cenozoic sedimentary rocks. the Aves Ridge from the Lesser Antilles arc. In the south the The Caribbean Mountain System is an east-west trend- basin attains depths of about 3000 m, but to the north the ing belt that extends from de Santa Marta in 4 water depth decreases, and the Aves Ridge and Grenada the west to the island of Tobago in the east . Six thrust- Basin merge into a single platform called the Bank. bounded nappes outcrop discontinuously along the north Major lithospheric changes in the north and south of the coast of Venezuela These nappes consist of Cretaceous basin occur between latitudes 14°N and 15°N. To the south sequences that have been emplaced southward onto Paleo- the lithosphere is typical of a back-arc basin, composed of gene sedimentary rocks in a foreland basin setting. anomalously thick, two-layer oceanic crust similar to that of the nearby Venezuelan Basin40. This crust is overlain by Colombian Andes about 6 km of Tertiary volcaniclastic and pelagic sedimen- The major tectonic blocks included within the Colom- tary rocks 47. North of 15°N the basement is disturbed and bian Andes19 are, approximately from west to east, the is overlain by about 2 km of sediments and sedimentary Cordillera Occidental, the Cordillera Central, the Cordillera rocks11. The consensus of opinion is that the Grenada Basin Oriental, the Sierra Nevada de Santa Marta, the Sierra de is an intra-arc basin created by the splitting of a mature arc Perija and the Cordillera de Mérida, with associated sedi- during the early Paleogene into the Aves Ridge and the mentary basins (Donovan, chapter 13, herein). Lesser Antilles arc39. Alternately, the Grenada Basin may The Cordillera Occidental is a fault-bounded block be thinned forearc crust that became isolated during an consisting of a Mesozoic eugeosynclinal sequence devel- eastward migration of the subduction zone to its present oped on oceanic crust and intruded by Tertiary granitoid site23. plutons. It is separated from the Cordillera Central, which has a basement of continental crust, by the Romeral Fault GEOLOGIC PROVINCES-NORTHERN SOUTH Zone, which is characterised by a melange of oceanic and AMERICA continental fragments beneath a Tertiary cover sequence. The Cordillera Central is a polydeformed metamorphic Venezuelan borderland complex consisting of rocks from Precambnan to Creta- The Venezuelan borderland forms part of a broad oro- ceous, or uncertain, age55. A Precambnan to Palaeozoic genic belt of Mesozoic and Cenozoic rocks that mark the crystalline core includes a metamorphosed Lower Palaeo- boundary zone of the Caribbean with the South American zoic island arc sequence, and is overlain by Mesozoic to

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Geologic Provinces of the Caribbean Region

Cenozoic marine and continental deposits that have been ern Caribbean Plate Boundary. Journal of Geophysical intruded by plutons. The Sierra Nevada de Santa Marta to Research, 83,375-386. the north, a pyramidal, fault-bounded massif in isostatic 9Case, J.E. 1974. Oceanic crust forms basement of eastern disequilibrium, includes a similar sequence to the Panama. Geological Society of America Bulletin, 85, Cordillera Central. The Cordillera Oriental, Sierra de 645-652. Perija and Cordillera de Merida (=Venezuelan Andes) 10Case, J.E. & Dengo, G. 1982. The Caribbean region: in have broadly similar stratigraphies and structures, with Palmer, A.R. (ed.), Perspectives in Regional Geological Precambrian to Palaeozoic crystalline basement overlain Synthesis: Planning for the Geology of North America. by Palaeozoic to Cenozoic, mostly continental Geological Society of America DNAG Special sedimentary and volcanic sequences. The Cordillera Publication, 1,163-170. Oriental has been autochthonous on nuclear South America 11Case, J.E., Holcombe, T.L. & Martin, R.G. 1984. Map of since the Jurassic. geologic provinces in the Caribbean region. Geological Society of America Memoir, 162, 1-30. ACKNOWLEDGEMENTS—We thank Paul Mann (University of at 12Case, J.E., MacDonald, W.D. & Fox, P.J. 1990. Caribbean Austin) and Kirton Rodrigues (Trintoc, Pointe-a-Pierre) for making constructive review comments on this typescript crustal provinces: seismic and gravity evidence: in Dengo, G. & Case, J.E. (eds), The Geology of North America. Volume H. The Caribbean Region, 15-36. REFERENCES Geological Society of America, Boulder. 13Collins, L.S. & Coates, A.G. 1992. Timing and rates of 1 Arden, D.D., Jr. 1969. Geologic history of the Nicaraguan emergence of the northwestern Panama microplate: Rise. Transactions of the Gulf Coast Association of Caribbean effects of Cocos Ridge subduction? Geo- Geological Societies, 19, 295-309. logical Society of America Abstracts with Programs, 2 Arden, D.D., Jr. 1975. Geology of Jamaica and the Nicara- 24(7), A64. guan Rise: in Nairn, A.E.M. & Stehli, F.G. (eds), The 14Donnelly, T.W. 1973. Circum-Caribbean explosive vol- Ocean Basins and Margins. Volume 3. The Gulf of canic activity: evidence from Leg 15 sediments: in Mexico and the Caribbean, 617-661. Plenum, New Edgar, N.T. & Saunders, J. (eds), Initial Reports of the York. Deep Sea Drilling Project, 15, 969-988. 3 Beets, D.J., Maresch, W.V., Klaver, G.T., Mottana, A., 15Donnelly, T.W., Home, G.S., Finch, R.C. & Lopez-Ra- Bocchio, R., Beunk, F.F. & Monen, H.P. 1984. Mag- mos, E. 1990. Northern Central America: the Maya and matic rock series and high-pressure metamorphism as Chortis Blocks: in Dengo, G. & Case, J.E. (eds), The constraints on the tectonic history of the southern Car- Geology of North America. Volume H. The Caribbean ibbean. Geological Society of America Memoir, 162, Region, 37-76. Geological Society of America, Boul- 95-130. der. 4 Bellizzia, A. & Dengo, G. 1990. The Caribbean Mountain 16Draper, G. & Lewis, J.F. 1982. Petrology and structural system, northern South America: a summary: in Pengo, development of the Duarte complex, central Dominican G. & Case, J.E. (eds), The Geology of North America. Republic; a preliminary account and some tectonic Volume H. The Caribbean Region, 167-175. Geological implications: in Snow, W., Gil, N., Llinas, R., Ro- Society of America, Boulder. driguez-Torres, R., Seaward, M. & Tavares, I. (eds), 5 Bouysse, P., Andrieff, P., Richard, M., Baubron, J.C., Transactions of the Ninth Caribbean Geological Con- Mascle, A., Maury, R.C. & Westercamp, D. 1985. Aves ference, Santo Domingo, Dominican Republic, August Swell and northern Lesser Antilles ridge: rock-dredging 16th-20th, 1980,1, 53-64. results from ARCANTE 3 cruise: in Mascle, A. 17Draper, G. & Lewis, J.F. 1992. Metamoiphic belts in (ed.), Geodynamique des Caraibes, 65-76. Technip, central Hispaniola. Geological Society of America Special Paris. Paper, 262,29-45. 6 Bouysse, P. & Sigurdsson, H. 1982. The "Hodder Phe- 18Edgar, N.T., Dillon, W.P., Jacobs, C., Parsons, L.M., nomenon" of 1902: no active volcano off St. Lucia Scanlon, K.M. & Holcombe, T.L. 1990. Structure and (Lesser Antilles). Marine Geology, 50, 1-2,1129-1136. spreading history of the central Cayman Trough: in 7 Burke, K., Cooper, C., Dewey, J.F., Mann, P. & Pindell, La rue, D.K. & Draper, G. (eds), Transactions of the J.L. 1984. Caribbean tectonics and relative plate mo - Twelth Caribbean Geological Conference, St. Croix, tions. Geological Society of America Memoir, 162, U.S.V.L, August 7th-l1th, 1989,33-42. 31-63. 19Gansser, A. 1973. Facts and theories on the Andes. Journal 8 Burke, K., Grippi, J. & Sengor, A.M.C. 1980. Neogene of the Geological Society of London, 129,93-131. structures in Jamaica and the tectonic style of the North-

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20Gealey, W.K. 1980. Ophiolite obduction mechanisms: in Caribbean neotectonics: in Dengo, G. & Case, J.E. Ophiolites: Proceedings of the International Ophiolite (eds), The Geology of North America. Volume H. The Symposium, Cyprus, 1979, 243-247. Cyprus Geologi- Caribbean Region, 307-338. Geological Society of cal Survey Department, Nicosia. America, Boulder. 32 21Hildebrand, A.R., Penfield, G.T., Kring, D. A., Pilkington, Martin-Kaye, P.H.A. 1969. A summary of the geology of M., Camargo Z., A., Jacobsen, S.B. & Boynton, W.V. the Lesser Antilles. Overseas Geology and Mineral 1991. Chicxulub Crater: a possible Cretaceous/Tertiary Resources, 10, 172-206. 33 boundary impact crater in the Yucatan Peninsula, Mex- Mattson, P.H. 1960. Geology of the Mayaguez area, ico. Geology, 19, 867-871. Puerto Rico. Geological Society of America Bulletin, 22Holcombe, T.L. 1977. Caribbean bathymetry and sedi- 71, 319-362. 34 ments: in Weaver, J.D. (ed.), Geology, Geophysics and Mattson, P.H. & Pessagno, E.A., Jr. 1979. Jurassic and Resources of the Caribbean: Report of the IDOE Work - early Cretaceous radiolarians in Puerto Rican ophiolite shop on the Geology and Marine Geophysics of the - tectonic implications. Geology, 7,440-444. Caribbean region and its Resources, Kingston, Ja- 35Maury, R.C., Westbrook, G.K., Baker, P.E., Bouysse, P. maica, February 17-22, 1975,27-62. & Westercamp, D. 1990. Geology of the Lesser An- 23Holcombe, T.L., Ladd, J.W., Westbrook, G., Edgar, N.T. tilles: in Dengo, G. & Case, J.E. (eds), The Geology of & Bowland, C.L. 1990. Caribbean marine geology: North America. Volume H. The Caribbean Region, ridges and bas ins of the plate interior: in Dengo, G. & 141-166. Geological Society of America, Boulder. Case, I.E. (eds), The Geology of North America. Vol- 36Meyerhoff, A. A. & Kreig, E.A. 1977. Petroleum potential of ume H. The Caribbean Region, 231-260. Geological Jamaica. Special Report, Ministry of Mining and Society of America, Boulder. Natural Resources, Mines and Geology Division, Ja- 24Jackson, T. A. 1994. The marine geology and the maica, 131 pp. 37 non-living resources of the Caribbean Sea: an over- Perfitt, M.R. & Heezen, B.C. 1978. The geology and view. Caribbean Marine Studies, 2 (for 1991), 10-17. evolution of the Cayman Trench. Geological Society 25Ladd, J.W., Holcombe, T.L., Westbrook, G. & Edgar, of America Bulletin, 89, 1155-1174. N.T. 1990. Caribbean marine geology: active margins 38Pindell, J.L. 1985. Alleghenian reconstruction and the of the plate boundary: in Dengo, G. & Case, J.E. (eds), subsequent evolution of the Gulf of Mexico, Bahamas The Geology of North America. Volume H. The Carib and Proto-Caribbean Sea. Tectonics, 4,1-39. bean Region, 261-290. Geological Society of America, 39Pindell, J.L. & Barrett, S.F. 1990. Geological evolution of Boulder. the Caribbean region; a plate-tectonic perspective: in 26 Ladd, J.W., Truchan, M., Talwani, M., Stoffa, P.L., Buhl, Dengo, G. & Case, J.E. (eds), The Geology of North P., Houtz, R., Mauffret, A. & Westbrook, G. 1984. America. Volume H. The Caribbean Region, 405-432. Seismic reflection profiles across the southern margin Geological Society of America, Boulder. of the Caribbean. Geological Society of America Mem- 40Pinet, B., Lajat, D., Le Quellec, P. & Bouysse, P. 1985. oir, 162, 153-159. Structure of the Aves Ridge and Grenada Basin from 27 MacDonald, K.C. & Holcombe, T.L. 1978. Inversion of multichannel seismic data: in Mascle, A. (ed.), Geody- magnetic anomalies and sea floor spreading in the namique des Caraibes, 53-64. Technip, Paris. Cayman Trough. Earth and Planetary Science Letters, 41Pszczolkowski, A. & Flores, R. 1986. Fases tectonicas del 40,407-414. Cretacico y del Paleogeno en Cuba occidental y central. 28 Mann, P. & Burke, K. 1984. Neotectonics of the Carib- Bulletin of the Polish Academy of Sciences, 34, 95-111. bean. Reviews of Geophysics and Space Physics, 22, 42Renne, P.R., Martinson, J.M., Hatten, C.W., Somin, M.L., 309-362. Onstott, T.C., Millan, G. & Linares, E. 1989.40Ar/39Ar 29 Mann, P., Draper, G. & Buike, K. 1985. Neotectonics of and U-Pb evidence for late (Grenville-age) a strike slip restraining bend system, Jamaica: in Bid - continental crust in north-central Cuba and regional die, K.T. & Christie-Blick, N. (eds), Strike Slip Defor- tectonic implications. Precambrian Research, 42,325- mation, Basin Formation, and Sedimentation. Society 341. of Economic Paleontologists and Mineralogists Spe- 43Rosencrantz, E. 1990. Structure and tectonics of the Yu - cial Publication, 37,211-226. catan Basin, Caribbean Sea as determined from seismic 30 Mann, P., Hempton, M., Bradley, D. & Burke, K. 1983. reflection studies. Tectonics, 9,1037-1059. Development of pull-apart basins. Journal of Geology, 44Rosencrantz, E. & Mann, P. 1991. SeaMARC II 91,529-554. mapping of transform faults in the Cayman Trough. 31Mann, P., Schubert, C. & Buike, K. 1990. Review of Geology, 19, 690-693.

11

Geologic Provinces of the Caribbean Region

45Rosencrantz, E. & Sclater, J.G. 1986. Depth and age of July 10th-l2th, 1985,270-280. the Cayman Trough. Earth and Planetary Science Let- 52Tomblin, J.F. 1975. The Lesser Antilles and Aves Ridge: ters, 79,133-144. in Nairn, A.E.M. & Stehli, F.G. (eds), The Ocean 46Ross, M.I. & Scotese, C. 1988. A hierarchial tectonic Basins and Margins. Volume 3. The Gulf of Mexico and model of the Gulf of Mexico and Caribbean region. the Caribbean, 467-500. Plenum, . Tectonophysics, 155,139-168. 53McCann, W.R. & Pennington, W.D. 1990. Seismicity, 47Sigurdsson, H., Sparks, R.S.J., Carey, S. & Huang, T.C. large earthquakes, and the margin of the Caribbean 1980. Volcanic sedimentation in the Lesser Antilles Plate: in Dengo, G. & Case, I.E. (eds), The Geology of arc. Journal of Geology, 88,523-540. North America. Volume H. The Caribbean Region, 48Sheridan, R.E, Muffins, H.T., Austin, J.A., Ball, M.M. & 291-306. Geological Society of America, Boulder. Ladd, J.W. 1988. Geology and geophysics of the Baha- 54Torrini, R., Jr. & Speed, R.C. 1989. Tectonic wedging in mas: in Sheridan, R.E. & Grow, J. A. (eds), The Geology the forearc basin-accretionary prism transition, Lesser of North America. Volume 1-2. The Atlantic Continental Antilles forearc. Journal ofGeophysical Research, 94, Margin, 329-364. Geological Society of America, 10549-10584. Boulder. 55Toussaint, J.F. & Restrepo, J. J. 1982. Magmatic evolution 49Simkin, T., Siebert, L., McClelland, L., Bridge, D., Ne - of the northwestern Andes of Colombia. Earth-Science whall, C. & Latter, J.H. 1981. Volcanoes of the World. Reviews, 18,205-213. Smithsonian Institution, Washington D.C. & Hutchin- 56Uchupi, E. 1975. The physiography of the Gulf of Mexico son Ross, Stroudsburg, viii+232 pp. and the Caribbean Sea: in Nairn, A.E.M. & Stehli, F.G. 50Somin, M.L. & Millan, G. 1977. Sobre laedad de las rocas (eds), The Ocean Basins and Margins. Volume 3. The metamorficas Cubanas. Academia de Ciencias de Gulf of Mexico and the Caribbean, 1-64. Plenum, New Cuba, Informe Cientifico-Tecnico, 2, 1-11. York. 51Speed, R.C. 1986. Cenozoic tectonics of the southeastern 57Wadge, G. & Wooden, J.L. 1982. Cenozoic alkaline vol- Caribbean and Trinidad: in Rodrigues, K. (ed.), Trans- canism in the northwestern Caribbean: tectonic setting actions of the First Geological Conference of the Geo- and Sr characteristics. Earth and Planetary Science logical Society of , Port-of Spain, Letters, 57,35-46.

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