Analysis of seismic reflection data from the Northern Hispaniola margin: Implications for the recent evolution of the Northern Caribbean Plate boundary

Abstract

The northern margin of Hispaniola features an accretionary prism with morphological structures shaped by tectonic, hydrodynamic and sedimentary processes in oblique convergence between North American and Caribbean plates. The HAITISIS data in the northern Caribbean plate boundary elucidate the relationships between fault-driven tectonic activity, seafloor morphology, and effects of transpressional deformation. We evidence an E-W-trending spatial variation in deformation accommodation and sedimentary records along the accretionary prism. The distinct morpho-structural character of the seafloor and sedimentation patterns originated during the Upper Miocene-Pliocene tectonic reorganization of the northern Caribbean Plate boundary, which is associated with the onset of the oblique collision of the Caribbean and North American Plates carrying Hispaniola to the transpressive plate boundary opposite the Bahamas Carbonate Platform. An accretionary prism is formed, and segments of the eastern strand of the Septentrional-Oriente Fault Zone (SOFZ) are activated, resulting in lateral sediment source displacements, influencing sedimentary infill and deformation patterns.

A mass transport deposit (MTD) in the Eastern domain caused differential compaction and remobilization of recent seismic units and has affected the seafloor morphology. The MTD is absent in the Western domain, and canyons are found in the Eastern domain.

The early Miocene SOFZ onset and evolution is not a continuous eastward propagation. Lateral displacements of canyons provide a chronology for strike-slip and thrust faults before the SOFZ initiation and the formation of the current fault segments. The variations in fault density, cumulative displacement along strike-slip faults, morphology of Northern Hispaniola insular slope (including width and tectonic style), and tilting of basin surfaces suggest the underthrusting of the North American plate beneath the Caribbean plate has ceased at the transition between the Eastern and Western domains. This may be attributed to westward rheological transition of North American plate's crust (from oceanic to continental) at the level of the Bahamas platform.