Recent Sedimentary Environment of Pensacola Bay, Florida

Sheri M. George, Wayne C. Isphording, Maurice A. Meylan

The Pensacola Bay system represents the largest coastal estuary in the Florida panhandle region and covers an area of nearly 400 km². The system includes Pensacola, Escambia, East, and Blackwater Bays, and serves as the terminus for rivers draining a watershed area of some 17,500 km². The Blackwater, Yellow, and Escambia Rivers are the major streams entering the bay system, with the latter originating over 250 km from the mouth of the bay, in eastern Alabama.

Because of the restricted water circulation patterns and the relatively narrow opening afforded to the Gulf of Mexico, most of the sediments that are carried into the bay become incorporated as bottom detritus. As a result, not only is the bay undergoing a gradual infilling but deltas also are prograding into the bay at the mouths of the three major rivers.

Unlike many other bays in the northern Gulf of Mexico, however, Pensacola Bay appears to have largely escaped the impact of man, at least with respect to changes in basic patterns of sedimentation. Prior studies of the sediments carried out 20 years ago bear a striking similarity to the results of the present investigation in terms of the areal distribution of sediment types and the mineralogy of the bottom sediments. Although a distinct coarsening of the sediments over time was observed at the head of Escambia Bay as a consequence of quarrying operations upstream, the overall distribution of sediment types throughout the remainder of the bay has remained essentially unchanged.

AAPG Search and Discovery Article #91036©1988 GCAGS and SEPM Gulf Coast Section Meeting; New Orleans, Louisiana, 19-21 October 1988.