TECTONIC DEVELOPMENT OF THE CUBAN ACCRETIONARY BELT

The Cuban segment of the Antillean orogenic belt formed during the Mesozoic-Cenozoic at the boundary zone between the North American and Caribbean Plates. This Cuban segment is made of distinctive geologic units including Neoproterozoic rocks, Mesozoic oceanic elements, Cretaceous and Paleogene volcanic arc suites, Mesozoic continental passive margin elements, as well as Latest Cretaceous trough Eocene foreland and piggyback synorogenic basins. Latest Eocene and younger post-orogenic sedimentary rocks overlie the foldbelt. The process of formation of accretionary wedges was initiated within an oceanic environment at the Lower Cretaceous (Aptian-Albian), documented in serpentinite-matrix mélanges formed and exhumed at 120-110 Ma. But the major features of the architecture of the Cuban belt formed during the latest Campanian through Eocene, and ended with the amalgamation of Mesozoic continental margin, oceanic crust and Cretaceous volcanic arc terranes. During this process took place a) the exhumation of the subducted Pinos and Escambray terranes and of oceanic lithosphere slices within the Escambray terrane about 70-65 Ma ago, b) the extinction of the Upper Cretaceous volcanic-arc activity in the Campanian, and c) the metamorphism of volcanic-arc rock sections during the Maastrichtian. Only in Eastern Cuba (Sierra Maestra-Cayman ridge) volcanic activity started at the Paleocene and lasted until the Middle Eocene. Such scenario of coeval convergence, arc-volcanism, and tectonic extension during this stage of development of the accretionary belt was likely the result of an important plate-tectonic reconfiguration of the Caribbean region at the Paleocene. This tectonic history agrees with a Pacific origin for the Caribbean plate, but do not accommodate into any of the available plate tectonic models for the Caribbean.