Cenozoic tectonic history of the North America‐Caribbean plate boundary zone in western Cuba

Abstract

Structural studies of well‐dated Jurassic to lower Miocene rocks in western Cuba constrain the sequence of structural events affecting this oblique collisional zone between the late Cretaceous island arc and the Jurassic‐Cretaceous North America passive margin in the southeastern Gulf of Mexico and Straits of Florida. Results of detailed mapping and collection of fault slip data at 34 sites define a regionally consistent, five phase tectonic model for the period from the late Paleocene to the post‐early Miocene. During the late Paleocene to the early Eocene, the Cuban island arc collided with the North American passive margin (Bahamas Platform). Northwest‐ward overthrusting during the collision defines tectonic phase I. A NNE‐SSW compression concurrent with early Eocene left‐lateral strike‐slip faulting along the Pinar fault zone defines phase II. This result is consistent with structural mapping showing sinistral shear within the 065° striking Pinar fault zone. An ENE‐WSW to E‐W compression defining phase III overprinted phase II faults in the lower Eocene and older rocks. Post‐early Miocene normal faulting characterizes phase IV. Inversion of fault slip data indicates two contemporaneous directions of tension of 120 and 170. Strike‐slip faults that overprint phase IV normal faults yield a 120 compression (phase V). The direction of compression associated with the arc/continent 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 middle Eocene (phase III). The rotation in the compression direction occurred because the arc turned toward an oceanic area in the present‐day area of central and eastern Cuba. Progressive collision led to complete subduction of the remnant oceanic crust by middle to late Eocene time.