Florida keys

Abstract

The late Quaternary depositional system along the shallow Florida Keys shelf was physically and biologically predisposed to replicate the structures, forms, and processes of antecedent outer-shelf and shelf-edge morphologies. Primary controls were the position of sea-level maxima relative to antecedent topography. Reefs responded to the resultant ambient geomorphic settings in their growth habits, vitality, and distribution. Post-125-ka Pleistocene settings offered accommodation space and protection, and shelf-edge reefs flourished. The Holocene transgression flooded the shelf, ultimately creating conditions that allowed tidal exchange of coastal bay and cold gulf waters with the reefs, causing their decline. The rock record shows that reef growth varied locally through time—in location, dimension, structure, geometry, depth, age distribution, and accretionary direction. Yet the recurring regional theme is the replication of antecedent facies and geomorphic landforms, and thus repetition of stratigraphic shelf-edge asymmetry. Florida Keys reef morphologies are distinctly different from what would be generated at a classic steeply inclined windward margin.