Boreholes at Great Isaac and Site 626 and the history of the Florida Straits

Abstract

The stratigraphy of the top 2100 m of the Great Isaac 1 well was tied to recent seismic surveys of the area and correlated with ODP Site 626. The Great Isaac succession includes shallow-water carbonate-evaporite deposits (late Cretaceous and older) overlain by deep-water deposits with upward increasing neritic debris (late Cretaceous-Tertiary) and capped by bank-margin deposits (Plio-Pleistocene). This succession is interpreted as a restricted carbonate platform that drowned in the Albian-Cenomanian and was subsequently reintegrated into the Great Bahama Bank by westward progradation of the platform. This and the fact that the drowned Cretaceous platform also underlies the Florida Straits in this area support the hypothesis that until the mid-Cretaceous, Florida and the Bahamas were welded into a single large platform, the mega-bank. -after Authors