How transpressive is the northern Caribbean plate boundary?
Résumé
Transpressive deformation at the northern Caribbean plate boundary is accommodated mostly by two major strikeslip
faults, 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 along
this plate boundary around Hispaniola, in the Jamaica Passage and in the Gulf of Gonâve. The data set allows us to image
the offshore active strike-slip faults as well as the compressional structures. We confirm that the Enriquillo-Plantain-Garden
Fault Zone (EPGFZ) in the Jamaica Passage has a primary strike-slip motion, as indicated by active left-lateral strike-sliprelated
structures, i.e.: restraining bend, asymmetrical basin, en echelon pressures ridges and horsetail splay. Based on
topographic cross-sections across the EPGFZ, we image a very limited compressional component, if any, for at least the
western part of the Jamaica Passage. Toward the east of the Jamaica Passage, the fault trace becomes more complex and we
identify adjacent compressional structures. In the Gulf of Gonâve, distributed folding and thrust faulting of the most recent
sediments indicate active pervasive compressional tectonics. Estimates of shortening in the Jamaica Passage and in the Gulf
of Gonâve indicate an increase of the compressional component of deformation towards the east, which nonetheless remains
very small compared to that inferred from block modelling based on GPS measurements
Domaines
Sciences de la TerreOrigine | Fichiers produits par l'(les) auteur(s) |
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