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Migrating Twin Left-Lateral Faults System Along the North Caribbean Boundary – Implications on Geodynamics Around the Haiti-Cuba Boundary

Abstract

N. Caribbean plate boundary around Haiti is characterized by a complex left-lateral fault system presently delineating the transpressive Trans-Haitian Ranges. Motion along these faults accommodated the expulsion of the Caribbean plate to the East since millions of years.. Could we consider that their position along the crustal limits are permanent, as the E-W development of the Cayman Through suggest along the Oriente septentrional Fault (at least since the lower Miocene times)? In the prolongation of Cayman through, field work and oceanographic surveys respectively on Haiti and offshore between Cuba, Jamaica and Haiti have been acquired from 2012 to 2015. From seismic and field work interpretation, we show that the present-day traces of strike-slip faults are cross-cutting different pre-existing crustal and basin structures, and that they are also expressed by a strong instability through time. These seismically very active twin-fault system propagate toward the East in Haiti, and, in between, triggered by the oblique convergence, the Transhaitian fold-and-thrust belt developed. From ancient and our studies, it is demonstrated that sedimentary sequences involved in the thrust Units, as well as in the restored foreland units are of different nature, not only along dip but also along strike, as deposited in various geodynamical and crustal contexts. The restoration of the oblique shortening coupled with a tentative sedimentary synthesis for each environmental context allow to restitute more precisely the paleogeography of the area. We discuss the geodynamics of the North central Caribbean plate boundary and the implications on the origin and potential of each of the blocks involved in the surroundings of Haiti.