Paper No. 275-14
Presentation Time: 11:20 AM
ANIMATION OF THE TECTONIC EVOLUTION OF CUBA
Cuba was formed by amalgamation of three tectonic domains of differing origin: the continental margin formed along the Bahamas-southern Florida portion of the North American margin in the Jurassic, a displaced part of the Yucatan margin, and arc-derived terranes formed along the Pacific margin of the evolving Caribbean region. The arc terranes form a complex thrust stack that is allochthonous onto the continental margin. Within the arc terranes there are rocks formed along two arc systems: the ‘Great Arc of the Caribbean’, an eastward directed subduction system that lasted from Jurassic to at least mid Cretaceous time, and a subsequent subduction system resulting from eastward motion of the Caribbean Plate. In spite of the complex structure that amalgamation of these diverse domains has created on Cuba, it is possible to define major blocks that can be used to illustrate formation of the island. From west to east there are four major blocks, starting with the Guaniguanico terrane in the west. This is interpreted as a continental margin terrane, probably originating from eastern Yucatan. This terrane is bounded on its east side by the left-lateral Pinar strike-slip fault. The other three major Cuban terranes that lie east of this fault are arc-derived. The westernmost is the La Habana/Santa Clara Block that extends eastwards to the left-lateral La Trocha fault. Next is the Camaguey block, reaching to the Cauto and Nipe basins. Finally there is the southeastern most block of Cuba, the Sierra Maestra/Oriente block. In this presentation we illustrate evolution of Cuba with an animation showing rifting of Pangea, formation of the terranes, and their subsequent amalgamation into present-day Cuba. We emphasize some of the parts of this evolution that are still poorly understood, including the extent of the North American continental margin that underlies Cuba. Some interpretations show margin all the way to the southern edge of Cuba such that the North American limit of Jurassic oceanic crust is along the southern margin of Cuba. Although possible, we show that pushing the southern edge of North America this far outboard is difficult to reconcile with pre-rift Pangea reconstructions. We will also address how the Callovian evaporite deposits of Cuba may be connected to the similar aged Louann salt deposits of the northern Gulf of Mexico.