Abstract Within the last decade, modern petrological and geochronological methods in combination with detailed studies of the field geology have allowed the reconstruction of tectonic processes in the northwestern part of the Caribbean Plate. The development of an oceanic Proto-Yucatán Basin can be traced from the Late Jurassic to the Mid-Cretaceous. From the Mid-Cretaceous onward, an interaction of this basin with the Caribbean Arc can be observed. Geochronological data prove continuous magmatic activity and generation of HP mineral suites in the Caribbean Arc from the Aptian to the Campanian/Maastrichtian. Magmatism ceased at least in onshore central Cuba at about 75 Ma, probably as the southern edge of the continental Yucatán Block began to interact with the advancing arc system. Similarly, the youngest recorded ages for peak metamorphism of high-pressure metamorphic rocks in Cuba cluster at 70 Ma; rapid uplift/exhumation of these rocks occurred thereafter. After this latest Cretaceous interaction with the southern Yucatán Block, the northern Caribbean Arc was dismembered as it entered the Proto-Yucatán Basin region. Because of the continued NE-directed movement, Proto-Yucatán Basin sediments were accreted to the arc and now form the North Cuban fold and thrust belt. Parts of the island arc have been thrust onto the southern Bahamas Platform along the Eocene suture zone in Cuba. Between the arc's interaction with Yucatán and the Bahamas ( c . 70 to c . 40 Ma), the Yucatán intra-arc basin opened by extreme extension and local seafloor accretion between the Cayman Ridge (still part of Caribbean Plate) and the Cuban frontal arc terranes, the latter of which were kinematically independent of the Caribbean. Although magmatism ceased in central Cuba by 75 Ma, traces of continuing Early Palaeogene arc magmatism have been identified in the Cayman Ridge, suggesting that magmatism may not have ceased in the arc as a whole, but merely shifted south relative to Cuba. If so, a shallowing of the subduction angle during the opening of the Yucatán Basin would be implied. Further, this short-lived (?) Cayman Ridge arc is on tectonic strike with the Palaeogene arc in the Sierra Maestra of Eastern Cuba, suggesting south-dipping subduction zone continuity between the two during the final stages of Cuba–Bahamas closure. After the Middle Eocene, the east–west opening of the Cayman Trough left the present Yucatán Basin and Cuba as part of the North American Plate. The subduction geometry, P–T–t paths of HP rocks in Cuban mélanges, the time of magmatic activity and preliminary palaeomagnetic data support the conclusion that the Great Antillean arc was initiated by intra-oceanic subduction at least 900 km SW of the Yucatán Peninsula in the ancient Pacific. As noted above, the Great Antillean Arc spanned some 70 Ma prior to its Eocene collision with the Bahamas. This is one of the primary arguments for a Pacific origin of the Caribbean lithosphere; there simply was not sufficient space between the Americas, as constrained by Atlantic opening kinematics, to initiate and build the Antillean (and other) arcs in the Caribbean with in situ models.

Abstract Many models that attempt to interpret the regional geology of the Caribbean-Gulf of Mexico area share the handicap of paying little attention to precise data from Cuba despite its location at the North American-proto-Caribbean paleoboundary. The North American Mesozoic paleomargin crops out along northern Cuba, an area where many wells have encountered Jurassic and Lower Cretaceous rocks. In this chapter, we present a stratigraphic interpretation of the North American passive continental paleomargin recognized in the Guaniguanico mountains (western Cuba) and identify the main geological events recorded in their Oxfordian to Berriasian sections. We correlate these sections with other Mesozoic passive paleomargin sections in Cuba, including the Escambray and Isle of Youth metamorphic terranes. These sections and those in the southeastern Gulf of Mexico record early stages of the disintegration of Pangea in Mesoamerica and the early development of the southeastern Gulf of Mexico and westernmost Tethys (proto-Caribbean). In all, two main sequences can be distinguished: (1) a lower terrigenous one and (2) an upper marine carbonate sequence. The transition from terrigenous to carbonate sedimentation occured during the late middle Oxfordian in western Cuba (and possibly in the Escambray mountains of central Cuba). In Placetas zone of central Cuba, the terrigenous-carbonate transition spans from Kimmeridgian to Berriasian. Transgression occurred close to the Kimmeridgian–Tithonian boundary. Deeper depositional conditions started during the Tithonian along the paleomargin in northern Cuba. This event may be correlated with the beginning of the drowning and stepback of the small carbonate platforms developed in the southeastern Gulf. Spreading and rifting ceased in the southeastern Gulf of Mexico when the Yucatan block reached its present position in the earliest Cretaceous. The unconformity that records the change in tectonic setting is called the late Berriasian surface, but our reinterpretation of biostratigraphic data indicates that the age of generalized flooding is middle Berriasian. In middle and late Berriasian times, a belt of deep-water carbonates surrounded the northern margin of the proto-Caribbean (westernmost Tethys). Extensive carbonate banks developed on the Bahamas-Florida platform and surrounded the emergent Yucatan Platform.

Restoration of plate consumption recorded by Caribbean arc volcanism reveals probable plate movements that led to the emplacement of the proto–Caribbean plate into the present Caribbean region and provided the space necessary to accommodate the rotation of the Yucatán Peninsula concurrent with the opening of the Gulf of Mexico between ca. 170 Ma and 150 Ma. Fault movement of the Yucatán, caused by edge-driven processes, resulted in counterclockwise rotation, as shown by paleomagnetic studies. Restoration of Yucatán rotation necessitates the presence of a paleogeography different from the current distribution of the Greater and Lesser Antilles. During emplacement of the Caribbean plate region, four magmatic belts with distinct ages and different geochemical characteristics are recorded by exposures on islands of the Antilles. The belts distinguish the following segments of Cretaceous and Tertiary magmatic arcs: (1) an Early Cretaceous geochemically primitive island-arc tholeiite suite (PIA/IAT) typically containing distinctive dacite and rhyodacite that formed between Hauterivian and early Albian time (ca. 135–110 Ma); (2) after a hiatus at ca. 105 Ma of ∼10 m.y., a voluminous, more-extensive calc-alkaline magmatic suite, consisting mainly of basaltic andesite, andesite, and locally important dacite, developed beginning in the Cenomanian and continuing into the Campanian (ca. 95–70 Ma); (3) a second (calc-alkaline) suite, spatially restricted relative to the older belts, that consists of volcanic and intrusive rocks, which formed between the early Paleocene and the middle Eocene (ca. 60–45 Ma); and (4) a currently active calc-alkaline suite in the Lesser Antilles typically composed of a basalt-andesite-dacite series that began to develop in the Eocene (ca. 45 Ma). Plate convergence took place along northeastward- or eastward-trending axes during the formation of the Caribbean, which is outlined by the Antillean islands and Central and South America. Movements were facilitated by strike-slip faults, commonly trench-trench transforms, as subducting crust was consumed. Restoration of apparent displacements of at least several hundreds of thousands of kilometers along the inferred lateral faults of the Eocene and younger Cayman set separating Puerto Rico, Hispaniola, and the Oriente Province of southeastern Cuba brings together Eocene volcanic rocks revealing a magmatic domain along the paleo–south-southwestern margin of the Greater Antilles. The transforms along the southern margin of the Caribbean plate are mainly obscured by contractional deformation related to the northward motion of South America as it was thrust over the faulted plate margin. Restoration of the Caribbean plate also translates the Nicaragua Rise westward, thereby revealing a pathway along which Pacific oceanic lithosphere, mainly composed of a large, Late Cretaceous igneous province (Caribbean large igneous province), manifest as an oceanic plateau (Caribbean-Colombian oceanic plateau), converged toward and subducted beneath the southern flank of the Cretaceous Greater Antilles magmatic belt between 65 and 45 Ma. The Eocene arc rocks overlie or abut previously recognized Early and Late Cretaceous subduction-related units. Eocene consumption of Pacific lithosphere ceased with the arrival, collision, and accretion of buoyant lithosphere composed of Caribbean large igneous province. The Greater Antilles formed during Late Cretaceous subduction of Jurassic ocean crust beneath an Early Cretaceous arc formed at the eastern margin of the proto–Pacific plate. Formation of a volcanic edifice above Early Cretaceous arc rocks was followed by plate collision and coupling of the Greater Antilles belt against the Bahama Platform. The most straightforward path of the Greater Antilles into the Caribbean is along northeast-striking transforms, one of which coincided with the eastern margin of the Yucatán Peninsula. The transform appears to link the Motagua suture to the Pinar del Rio Province of western Cuba. To the southeast, the arc was transected by a second transform, perhaps coinciding with the present trace of the Romeral fault in northwestern South America and extending northeast to the eastern terminus of the Virgin Islands. During Late Cretaceous convergence, a segment of the extinct Early Cretaceous arc, developed at the Pacific margin, was carried northeastward.

Abstract Rosenfeld and Pindell (2002 , 2003 ) hypothesized that late Paleocene-early Eocene docking of the northward migrating Caribbean Plate blocked the 200 km strait between the Florida/Bahamas Block and Yucatan, thereby isolating the Gulf of Mexico from the world ocean (Fig. 1) . Within several thousand years, net evaporation in the Gulf lowered its level by about 2,000 meters and formed a land bridge across the eastern Gulf that encompassed Yucatan, Florida, Cuba, and the Bahamas (Fig. 2) . Formation of the land bridge was enhanced by isostatic uplift of the basin’s margins as sea level dropped. After about 1 Ma of isolation, reconnection with the world ocean resulted in energetic refill of the basin that cut a deep thalweg between Florida and Cuba (Fig. 3) . This relatively short duration drawdown explains many phenomena unique to this period of Gulf history, including: the excavation of deep canyons across contemporary continental shelves and slopes: e.g ., Yoakum ( Figs. 4 , 5 , and 6 ), St. Landry, Chicontepec/Bejuco-La Laja ( Figs. 7 and 8 ) paleocanyons, and the many canyons found along the lower continental slopes of Florida and Yucatan (discussed below) the sudden deposition, and equally sudden cessation of a widespread, thick, high net sand blanket in the deep Gulf Basin ( Figs. 9 and 10 ) salt deposition in the barred Tertiary Veracruz Basin (Fig. 11) an unconformity in the eastern, carbonate-dominated Gulf Basin (Fig. 12) . Figure 1. The Cuban Arc at the leading edge of the northward moving Caribbean Plate sealed the entrance to the Gulf of Mexico at the end of the Paleocene. Figure 2. Isolation of the Gulf led to a ~2,000 meter drawdown of its level forming a hypersaline inland sea separated from the Atlantic and Caribbean by an extensive land bridge. Figure 3. Breaching of the barrier cut a deep channel through the Florida Strait cut into lithified Cretaceous carbonates. Data from DSDP 77 (1980-81). Figure 4. Map of the Yoakum and other paleocanyons of the northern Gulf of Mexico eroded into contemporaneous shelves during lowered sea level. Figure 5. Map of the Yoakum paleocanyon that is cut across at least 100 km of the paleoshelf. Figure 6. Cross section of the Yoakum paleocanyon cut 1200 m into the Lower Wilcox paleoshelf. Excavation and backfill of the canyon occurred within 1 Ma. Remobilization of Lower Wilcox shelf sand is probably the main contributor to the Wilcox “Whopper Sand” of the deep Gulf basin. Figure 7. Location of Chicontepec and other paleocanyons around the Tuxpan Platform, eastern Mexico. Figure 8. The Lower part of the Chicontepec paleocanyon that was cut from west to east (left to right in the figure) into lithified Cretaceous and Jurassic carbonates. Deep-water carbonates of Poza Rica Field experienced porosity enhancement from freshwater diagenesis during lowered sea level. Figure 9. Distribution of Wilcox sandstone across several hundred kilometers in the deep Gulf Basin shown in yellow (from Rains, Zarra, and Meyer, 2008). Wilcox sandstone under the present day shelf (Davy Jones and other wells) suggests that the sand blanket is also extensive in the north-south, as well as the east-west direction. The Wilcox has been found to continue south into the deep basin offshore Mexico. Figure 10. The sharply defined base and top of the “Whoppper Sand” in the Shell Great White well indicates the sudden start and cessation of sand deposition consistent with rapid eustatic changes. Figure 11. Log of the Mataespino 101B well of the Tertiary Veracruz basin, Mexico showing salt of probable playa lake origin buried by marine shale. The Veracruz basin is separated from the Gulf of Mexico by the Anegada high, which led to lowstand isolation and desiccation. Figure 12. Erosional unconformity in the western deep Gulf of Mexico Basin formed during lowstand. The seismic line location is indicated by the white line in the inset map. The drawdown is coeval with the worldwide Paleocene-Eocene thermal maximum (PETM) possibly triggered by the release of voluminous methane from destabilized hydrates and breached conventional reservoirs of the Gulf at low stand. The drawdown also profoundly affected the petroleum geology of the Gulf of Mexico, most obviously by deposition of basal Wilcox “Whopper Sand” reservoirs in U.S. and Mexican waters. Further petroleum ramifications include porosity enhancement by fresh water infiltration and leaching of reefal carbonates of the Golden Lane Atoll and deep-water carbonate detritus reservoirs in the Poza Rica Trend and Campeche Sound K/T breccias. Although a “smoking gun” has not yet been recognized that induces general acceptance of the Paleocene-Eocene Gulf drawdown, convincing evidence may be on the deep-water slopes of western Florida and northeastern Yucatan where sinkholes ( Figs. 13 and 14 ) are present, and steep-walled canyons are observed ( Figs. 15 , 16 , and 17 ) resembling those along eroded escarpments in present-day sub-aerial environments (Fig. 18) . Figure 13. Location map for sinkholes of Figure 14 . Figure 14. Sinkholes on the Florida slope at approximately 1,000 meters of depth. Figure 15. Location map for canyons of Figures 16 , 17 and 18 . Figure 16. Typical bathymetry of steep walled canyons along the lower Florida slope. Profile shown in the inset indicates that the canyons are cut into hard rocks. Figure 17. The Florida Canyon is the largest canyon cut into the Florida slope. Figure 18. Typical lower Florida slope canyon bathymetry compared to the eroded scarp of the Panamint Range, Death Valley, U.S.A. at about the same scale. With increased investigation of the eastern Gulf, the author is confident that definitive evidence will be found that either supports or eliminates the proposed drawdown. Meanwhile, explorers are encouraged to include the idea among their working hypotheses.

Abstract A thick, calcareous, clastic megabed of late Maastrichtian age has been known for sometime in western and central Cuba. This megabed was formed in association with the bolide impact at Chicxulub, Yucatán, at the K/T boundary, andiscomposed of a lower gravity-flow unit and an upper homogenite unit. The lower gravity-flow unit is dominantly composed of calcirudite that was formed because of collapses of the Yucatán, Cuban, and Bahamian platform margins and subsequent accumulation in the lower slope to basin margin environment. The gravity flow probably was triggered by a seismic wave induced by the impact, although a ballistic flow may have triggered collapse in the case of proximal sites (Yucatán margin). The upper homogenite unit is composed of massive and normally graded calcarenite to calcilutite that was formed as a result of large tsunamis associated with the impact and deposited in wider areas in the deeper part of Paleo-western Caribbean basin. Slight grain-size oscillations in this unit probably reflect the influence of repeated tsunamis. The large tsunamis were generated either by the movement of water into and out of the crater cavity or by the large-scale slope failure on the eastern margin of the Yucatán platform. In upper slope to shelf environments, gravity-flow deposits and homogenite are absent, and a thin sandstone complex influenced by repeating tsunami waves was deposited.