Lower Cretaceous-Upper Jurassic Carbonate Complex of Southern Margin of Florida-Bahama Platform in Northern Cuba

George O. Winston

Examination of core samples and cuttings from seven wells in northern Cuba has shown that the southern margin of the Florida-Bahama platform is composed largely of dolomitized carbonate mound and talus material. Dolomitization is possibly due to reflux of the highly saline waters from the South Florida evaporite basin to the north.

At least four separate episodes of mound construction are present, accompanied by seaward talus material. South of the dolomitized carbonate complex, three wells penetrated a deeper water continental slope facies consisting principally of light-colored limestone with uncommon beds of shale and radiolarian limestone. Zones of shallower facies appear to be intercalated. Farther to the south beyond the scope of this study, volcanics and serpentine are reported in the literature.

The northernmost wells on the island are cut by one or more high-angle thrust faults. Intense crumpling and faulting are present in the deeper water facies between the continental margin complex and the oceanic volcanic-serpentine province. The intense crumpling was probably caused as the deep-water sediments were scraped off by the subduction of an oceanic plate from the south beneath the continental crust of the Florida-Bahama platform.

Certain beds in the northern Cuba carbonate complex can be correlated with the standard section in Florida, as exhibited in the Cay Sal well to the north.

Three anhydrite beds in the Cayo Coco well appear to correlate with thick anhydrites in the Punto Gorda, Pumpkin Bay, and Bone Island formations. In the Collazo well to the south, a limestone-anhydrite section appears to correlate with the Pumpkin Bay.

Three limestone intervals in the Blanquizal well seem to correlate with portions of the Rattlesnake Hammock, Pumpkin Bay, and Bone Island formations in the Cay Sal well.

AAPG Search and Discovery Article #91036©1988 GCAGS and SEPM Gulf Coast Section Meeting; New Orleans, Louisiana, 19-21 October 1988.