Résumé
During Eocene, the North American plate motion switched from south-southwestward to westward while the Caribbean plate keeps moving slowly to the north. Along the northern Caribbean plate boundary this kinematic change is synchronous with the subduction of the Bahamas bank and its collision with the volcanic arc of Cuba that ultimately lead to the suture of the subduction zone along the Cuban segment and arc volcanism cessation. A major plate boundary re-organization thus occurred consequently to this suture as the Caribbean plate boundary jumped from the Cuban segment to the Cayman through. Synchronously, along the eastern boundary of the plate, volcanism initiated along the Lesser Antilles arc and the Grenada basin opened along N40 degrees E trending faults. Whereas widespread extension along N40 degrees trending faults has been previously recognized in the Yucatan basin and Nicaragua rise, from Early Eocene (Ypresian), extension localized along the Mid-Cayman trough spreading center, and is ceased in the Grenada basin. Haiti (western Hispaniola) is a key region to study this Eocene deformation phase. Indeed, it exposes onshore Eocene deformed strata as the northern boundary of the Caribbean plate underwent a late Oligo-Miocene NNE-SSW-directed shortening event that inverted these Eocene basins. Here, we investigate a compilation of marine geophysical data acquired in the Gonave Gulf, during Haiti SIS, SHA82 and FM0502 oceanographic cruises. We interpret 13 and 23 seismic profiles trending perpendicular respectively to the N40 degrees trending normal faults and to the NNW-SSE trending fold and thrust belts exposed onshore Haiti and Gonave island. Combined with a morpho-structural interpretation of the high-resolution bathymetric data we propose an offshore map of the surface deformation. We unravel N40 degrees E tilted blocks and their syn-sedimentary deposits farther east of the easternmost described hemi graben affecting the thinned crust of the Eastern Cayman through passive margin. We show that these units are affected by Oligo-Miocene shortening. We then discuss the relationships between the regional Eocene extension observed in the western and eastern Caribbean that display similar structural trends and integrate at a regional scale in order to bring insights into the geodynamical drivers of this widespread extension.