DETRITAL ZIRCON PROVENANCE STUDY OF SILICICLASTIC STRATA IN WESTERN AND CENTRAL CUBA: IMPLICATIONS FOR CARIBBEAN TECTONICS

Jurassic siliciclastic deposits in the greater Gulf of Mexico (GOM) region associated with the early Mesozoic breakup of western Pangea, host important hydrocarbon plays in the United States and Mexico. However, the origins, tectonic setting, and palinspastic position of the Jurassic deposits, in particular the siliciclastic deposits in western and central Cuba, remain enigmatic. In particular, the Mesozoic geology of Cuba is crucial for understanding the plate tectonics evolution of the greater Caribbean. The Pinar del Rio block of western Cuba contains outcrops of expansive Jurassic sandstone (San Cayetano Formation), while the internal portion of the Northern Cuban Fold Belt only has limited outcrops of Jurassic sandstone (Constancia Formation). While bio-and lithostratigraphic similarities suggest that the San Cayetano and Constancia strata are potentially correlative, the sedimentary provenance of these siliciclastic units is unknown, hampering tectonic and palinspastic reconstructions. Some tectonic models link the San Cayetano to the Maya block, while others attributed the San Cayetano and Constancia to the North American continental margin. Implementing a detailed detrital zircon (DZ) U-Pb provenance study of the Cuban Jurassic strata and comparing them to regional Jurassic siliclastic units will aid in our understanding of the origins of Cuban, Yucatan and the regional GOM area. The outcomes of this research will provide critical insights into Caribbean tectonic reconstructions and depositional environments in the early rifting stages of Pangea. Preliminary results from five western Cuban samples show a strong Grenvillian (Proterozoic) and Chiapas batholith (Permian-Triassic) signature while the central Cuban sample has a mid-late Paleozoic mode. By comparing this Cuban DZ data with that of the Jurassic Todos Santos formation in southern Yucatan, and the Norphlet formation in offshore Florida, we propose that that western Cuban Jurassic siliciclastic units are correlative with to the Todos Santos formation, adjacent to the Chiapas Massif. The central Cuban Constancia Formation appears to be related from the SW margin of the Maya Block and Yucatan but was eventually sheared off the Maya/Yucatan block during late Cretaceous emplacement of the Caribbean Plate.