An enormous carbonate megabank formed and thrived on the Nicaragua Rise in the Oligocene and early/middle Miocene, portions of which form the segmented platform/basin geometry seen today. Current intensification caused by this platform blocking the northward flow of the Caribbean Current resulted in widespread unconformities in the Florida-Bahamas region. The present study will connect three previous study sites by a network of high- resolution seismic profiles. Dredging of exposed outcrops and piston coring will provide samples of the older substrata. Eventually an ODP drilling program will be proposed for the Nicaragua Rise, based partly on the results of this program.