The geology of the Florida Keys

The Florida reefs have evolved over the last 7000 years during rising sea level. An ancient reef existed from sand shoals on which Miami and Key West are now sited before the last glaciation (100 000 to 125 000 years ago). During the glacial period sea level fell to >300 feet below its present level. Since sea level rose again invading the south Florida shelf again, corals have returned. The bulk of the Florida reef tract is composed of carbonate sand, some coming from corals but most from calcified algae. Future scenarios are considered for the Florida reefs assuming sea level to remain stable or to continue to rise. -J.G.Harvey