ABSTRACT
The middle and late Pliocene (early and late Piacenzian Age) saw the return of extended periods of warm, tropical climates and biogenic carbonate deposition on the Florida Platform. By the early Piacenzian, permanent upwelling systems had ceased off western Florida, and the Okeechobean Sea no longer received massive influxes of plankton blooms and nutrients. Because of the structural complexity of the pseudoatoll and its proximity to the Floridian mainland, the Tamiami subsea contained more types of tropical environments than were ever seen previously at any time in Florida's history. The main paleogeographical feature, the pseudoatoll, contained the highest number of depositional environments and ecological zones. The exceptionally diverse environments of the Tamiami Subsea created habitats for an unusually rich molluscan fauna that was replete with endemic local adaptive radiations. Within most units of the Tamiami formation, the remnants of these unique faunas exist as beautifully preserved, thick shell beds, often filling entire exposed sections.
