--> Abstract: Cenozoic Carbonate Platform Controls on a Modern Siliciclastic Coastal System, by A. C. Hine, S. D. Locker, G. Brooks, and R. A. Davis, Jr.; #90928 (1999).

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HINE, ALBERT C.1, STANLEY D. LOCKER1, GREGG BROOKS2, and RICHARD A. DAVIS, Jr.3
1 Department of Marine Science, University of South Florida
2 Department of Marine Science, Eckerd College
3 Department of Geology, University of South Florida

Abstract: Cenozoic Carbonate Platform Controls on a Modern Siliciclastic Coastal System

The modern barrier island/open-marine, marsh-dominated coastline of west central Florida is situated upon the middle of the Florida Platform — a major carbonate bank whose origins extend back into the Jurassic. Predominantly carbonate deposition ceased in the Neogene as the eastern portion of the Florida Platform received quartz sands from the north making the west Florida coastal plain, coastline, and shelf to be one of the largest mixed siliciclastic/carbonate depositional sites in the world.

Years of high resolution seismic reflection and side-scan sonar profiling coupled with numerous cores, bottom samples, and direct seabed observations have indicated that karst processes active since the Neogene have created antecedent topography that has controlled first-order coastal features such as the large estuaries situated on shelf valleys and headlands found along the modern coastal system. We propose that the two large estuaries on Florida's west coast resulted from deep-seated dissolution of underlying carbonates resulting from geothermally-stimulated Kohout-style groundwater convection.

In spite of a pronounced peneplanation of these Neogene age broadly folded and warped limestones, second order antecedent topography such as terraces have controlled the orientation of barrier islands and the size/shape of the back- barrier lagoons. Finally, numerous exposed limestone surfaces provide a substrate for carbonate producing organisms and more importantly, are subject to severe bioerosion which releases limestone rock fragments into the mobile sand cover. This is a third order influence that the former carbonate platform has on the modern depositional environment.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas