CENOZOIC TECTONIC HISTORY OF THE NORTH-AMERICA CARIBBEAN PLATE BOUNDARY ZONE IN WESTERN CUBA

Structural studies of well-dated Jurassic to lower Miocene rocks in we stern Cuba constrain the sequence of structural events affecting this oblique collisional zone between the late Cretaceous island are and th e Jurassic-Cretaceous North America passive margin in the southeastern Gulf of Mexico and Straits of Florida. Results of detailed mapping an d collection of fault slip data at 34 sites define a regionally consis tent, five phase tectonic model for the period from the late Paleocene to the post-early Miocene. During the late Paleocene to the early Eoc ene, the Cuban island are collided with the North American passive mar gin (Bahamas Platform). Northwest-ward overthrusting during the collis ion defines tectonic phase I. A NNE-SSW compression concurrent with ea rly Eocene left-lateral strike-slip faulting along the Pinar fault zon e defines phase II. This result is consistent with structural mapping showing sinistral shear within the 065 degrees striking Pinar fault zo ne. An ENE-WSW to E-W compression defining phase III overprinted phase II faults in the lower Eocene and older rocks. Post-early Miocene nor mal faulting characterizes phase IV. Inversion of fault slip data indi cates two contemporaneous directions of tension of 120 and 170. Strike -slip faults that overprint phase IV normal faults yield a 120 compres sion (phase V). The direction of compression associated with the arc/c ontinent collision rotates clockwise from NW-SE in the late Paleocene/ early Eocene (phase I), to NNE-SSW (phase II) and to ENE-WSW by the mi ddle Eocene (phase III). The rotation in the compression direction occ urred because the are turned toward an oceanic area in the present-day area of central and eastern Cuba. Progressive collision led to comple te subduction of the remnant oceanic crust by middle to late Eocene ti me.