How transpressive is the northern Caribbean plate boundary?

Description

Transpressive deformation at the northern Caribbean plate boundary is accommodated mostly by two major strikeslipfaults, but the amount and location of accommodation of the compressional component of deformation is still debated.We collected marine geophysical data including multi-beam bathymetry and multichannel seismic reflection profiles alongthis plate boundary around Hispaniola, in the Jamaica Passage and in the Gulf of Gonâve. The data set allows us to imagethe offshore active strike-slip faults as well as the compressional structures. We confirm that the Enriquillo-Plantain-GardenFault Zone (EPGFZ) in the Jamaica Passage has a primary strike-slip motion, as indicated by active left-lateral strike-sliprelatedstructures, i.e.: restraining bend, asymmetrical basin, en echelon pressures ridges and horsetail splay. Based ontopographic cross-sections across the EPGFZ, we image a very limited compressional component, if any, for at least thewestern part of the Jamaica Passage. Toward the east of the Jamaica Passage, the fault trace becomes more complex and weidentify adjacent compressional structures. In the Gulf of Gonâve, distributed folding and thrust faulting of the most recentsediments indicate active pervasive compressional tectonics. Estimates of shortening in the Jamaica Passage and in the Gulfof Gonâve indicate an increase of the compressional component of deformation towards the east, which nonetheless remainsvery small compared to that inferred from block modelling based on GPS measurements

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