JEE, JONATHEN L., University of Florida, Department of Geology, Gainesville, FL

ABSTRACT: Upper Cretaceous and Cenozoic Seismic Stratigraphy of the Western Florida Carbonate Platform

Analysis of 9,600 kilometers of multifold seismic lines and 29 wells, reveals the geologic history of the sedimentary section above the mid-Cretaceous sequence boundary (MCSB), offshore west Florida. Biostratigraphic data tied to magneto-biochronostratigraphic interpretations provide a chronostratigraphic framework of three main units, Upper Cretaceous, Paleocene-Eocene, and post-Eocene. Pre-existing basins and arches influenced the configuration of the MCSB surface which in turn affected thickness of the Upper Cretaceous-Cenozoic section.

There are two Upper Cretaceous subunits, UK1 (Cenomanian-Santonian) and UK2 (Campanian-Maastrictian). UK1 is fairly uniform, of continuous, parallel (even) seismic facies, but thickens in lows. Hummocky-to-contorted seismic facies and pronounced thickening of UK2 on a high on the MCSB, southwest of the Tenneco OCS-G-8363-1 suggests a constructional accumulation. A change to carbonate rock is indicated by sonic velocities in UK2 at this location, compared to Destin Dome wells where samples are fine-grained siliciclastic.

The Paleocene-Eocene unit is complex and contains several subunits. In the eastern Apalachicola Basin, these strata form two broad, en echelon, northwest-trending mounds with wavy, subparallel to hummocky seismic facies. About 50 km northeast of the Tenneco well, an arcuate zone of west-prograding complex clinoforms marks the Eocene shelf edge. Landward of the shelf edge, is a seismic "marbled zone" suggestive of dolomitic facies.

In the Apalachicola Basin, post-Eocene strata are continuous, parallel (even) and drape or infill Eocene structural features. In the Tampa Embayment, these strata form successive progradational sets of oblique, shingled, and sigmoid clinoforms.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.