The complex barrier/inlet system on the Gulf Coast of the Florida peninsula includes 30 barrier islands and a like number of tidal inlets. The diverse morphology of these elements gives rise to the most complicated barrier system in the world. Mean annual wave height is about 25cm and mean tidal range is less than one meter. Hurricanes are important but infrequent occurrences on this coast.

The siliciclastic, terrigenous component of this coastal complex is well-sorted, fine quartz sand with a mean grain size of about 2.6phi. The carbonate component is dominantly molluscan skeletal material although a few limestone rock fragments may also be present locally. Most of this molluscan skeletal material is from bivalves and is aragonitic in composition. The carbonate skeletal component of the barriers ranges in abundance from less than 10 percent to more than 80 percent locally. Although the gravel fraction of these sediments is essentially all skeletal, the sand fraction also contains abundant carbonate. This sand sized carbonate ranges from being essentially absent to more than 80 percent along the barrier coast.

Shell gravel is concentrated in the foreshore beach and in tidal-channel fill sequences. Carbonate sand is most abundant in the nearshore area. Such accumulations when preserved in the stratigraphic record could make excellent reservoirs upon dissolution of the carbonate fraction; both shell gravel and sand.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah