EVIDENCE FOR A MIDDLE TO LATE MIOCENE REGIONAL TECTONIC EVENT IN THE FLORIDA PENINSULA

The prevailing paradigm for deposition in Florida during Tertiary time is sedimentation in a tectonically quiescent environment in which the dominant structural process was slow subsidence. Data from multiple sources indicate that a tectonic deformation event impacted the Florida peninsular during the Miocene Epoch. Seismic reflection profiles and well data reveal the presence of subsurface folds with documented amplitudes of up to 100 m. The subsurface folds are completely buried by younger strata. Structural uplift in the southern Appalachians increased stream gradients, which allowed for the transport of coarse sand to pebble-sized quartz and feldspar down the length of the Florida peninsula. Chronostratigraphic data indicate that the main deformation in southern Florida occurred during the late middle to late Miocene (Serravallian to Tortonian, and perhaps into the Messinian). Some deformation may have continued into the Pliocene concurrent with continued deposition. The subsurface folding documented in Florida is a manifestation of regional tectonic activity, which includes a pulse of uplift of the South Appalachians and deformation on the Bahamian Platform related to the interaction of the Caribbean and North American plates.