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(a) Bathymetric map showing the positions of seismic sections collected during cruises HAITI‐SIS 1–2 (Leroy, 2012; Leroy & Ellouz‐Zimmermann, 2013; Leroy et al., 2015). Bold lines show the location of the seismic profiles shown in this paper. The short‐dashed black line represents the base of the insular slope. The large‐dashed black line represents the limit of the banks and ridges (b) Structural map of the study area based on the interpretation of seismic profiles. The focal mechanisms are for M > 5 earthquakes from the CMT database, except for the Mw 4.7, 17 Dec 2022 normal faulting on a NE‐SW oriented fault plane in the south of the Bahamas Carbonate province (c) representative bathymetric profiles across the insular slope of Eastern Cuba, revealing depths up to 3 km and slope gradients ranging from 11° to zero. Locations of the bathymetric profiles are shown in (b).
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The Eastern Cuban block has experienced a complex tectonic history characterized by plate interactions, resulting in a diverse array of geological features observable in the offshore sedimentary record. We investigate the tectonic evolution of offshore Eastern Cuba, specifically in the Old Bahamas Channel and its surrounding areas, by integrating m...
Citations
... Transects D and E show the variations in crustal thickness from the Cayman Trough pull-apart basin, across the tip of southeastern Cuba and the Windward Passage, across the GAC-BCP suture zone described from marine seismic reflection lines by Oliviera da Sá et al. (2024), and to the Columbus basin and Great Inagua Island on the BCP. Transect E extends to the eastern Nicaraguan Rise and Colombian basin and continues 390 km further to the southwest than transect D. ...
The 2–10‐km‐thick, mainly carbonate cap of the 14,000 km² Bahamas carbonate platform (BCP) has impeded imaging of its underlying crustal structure. The deeper structure of the BCP records both its Mesozoic rift and hotspot history and its later deformation related to its Paleogene collision with the Great Arc of the Caribbean (GAC). We use regional gravity data to model the crustal structure, type, and deformational processes of the BCP by: (a) integrating publicly available seismic data; (b) inverting the Moho along 2D regional gravity transects across the collisional zone; (c) modeling flexural uplift of a forebulge that reflects the attempted subduction of the BCP beneath the GAC; and (d) using downhole temperatures and radiogenic heat production in 1D basin models to differentiate crustal types related to the Mesozoic rift history. We interpret three crustal domains underlying the BCP: (a) 27–12‐km‐thick, rifted, and thinned continental crust of the northern Bahamas between the Blake Plateau and Exuma Sound; (b) 24–12‐km‐thick, volcanically‐thickened oceanic crust related to the Triassic‐Jurassic Bahamas hotspot in the central Bahamas southeast of Long Island; and (c) 20–12‐km‐thick, thickened oceanic crust north of Hispaniola. We propose that these crustal types reflect northwest‐southeastward, Triassic‐Jurassic rifting of the Bahamas region during the breakup of Pangea and accompanying magmatic activity related to the Triassic‐Jurassic Bahamas hotspot and early oceanic spreading. Growth of the BCP during the Cretaceous in this area was followed by Late Cretaceous‐Paleogene subduction‐related flexure and terminal Paleogene collision between the GAC and the BCP.
The southeastern coast of Cuba is bounded on the south by the Oriente Fault Zone that corresponds to the northern Caribbean plate boundary. By analyzing the coastal terraces of this region, we decipher the Pleistocene uplift along the transform plate boundary over a ~ 380 km long coastal stretch. We present a detailed mapping of uplifted coastal terraces and 18 new U/Th ages of corals. Upper Pleistocene uplift rates range from −0.02 ± 0.02 to 0.23 ± 0.07 mm.yr−1. From west to east, the coastal sequences exhibit a maximum of 18 terraces culminating at 270 m on Cabo Cruz, 11 terraces reaching 250 m near Santiago de Cuba and 29 terraces up to 520 m on Punta Maísi. Coastal sequences reveal distinct tectonic regimes. In the west at Cabo Cruz, uplift results from the tilting of tectonic blocks separated by NE-SW-trending normal faults, to the north of an extensional step-over of the Oriente Fault Zone. In the central part, the uplift is associated with NW-SE folding linked to a transpressional relay zone of the Oriente Fault Zone and to the offshore E-W Santiago Deformation Belt. In the east, at Punta Maísi, uplift results from a north-dipping thrust close to the coast linked with the oblique collision of the Bahamas platform against Cuba. The intensity of coastal uplift and locations of relay zones seems related to lateral variations in rheology and thickness of the tectonic plates. The uplift of the coast of SE Cuba is controlled by the oblique collision of the Bahamas platform of the North America continental plate against the continental crust of the Caribbean plate to the east and the oceanic/continental transition of the Caribbean plate to the West.
A widespread area of seafloor depressions ‐ circular, arcuate to elongated‐shaped ‐ has been found along the Northern Haitian coast, at water depths between 600 and 2,000 m. Characterized by wavelengths spanning several hundred meters and heights of tens of meters, these depressions are linked with a series of narrow ridges boasting varied morphologies. Our analysis integrating multichannel seismic reflection, high‐resolution bathymetry data, and sedimentological and geochemical evaluations of surface sediment cores indicates that present‐day seafloor morphology results from the interaction of slope bottom currents with the seafloor. The analyzed sediment cores exhibit hemipelagites, silty and sandy contourites, fine‐grained turbidites and reworked sand layers, implying sedimentation in a contourite drift system. This is further corroborated by seismic reflection data depicting wavy reflectors and aggradational stacking features typical of contourite drifts. Seafloor depressions are likely erosional features formed on the top of a contourite drift formed by the interaction of bottom currents with an irregular seafloor morphology. The seafloor equilibrium was initially disturbed by mass‐wasting events. Subsequently, the quasi‐steady flow of along‐slope bottom currents influenced sedimentary distribution and controlled the morphology of the seafloor depressions‐constant re‐shaping through erosion on their flanks. The resulting rough seafloor could have facilitated the destabilization of bottom currents and the development of erosive eddies responsible for the current morphology of the seafloor depressions. This study highlights the interplay between sedimentary processes (accumulation and compaction) and bottom currents, showing how their combined effects influence slope sedimentation and seafloor geomorphology, forming unique erosional features.
