ABSTRACT: Eustatic and Salt-Tectonic Controls on Sequence Development, Northern East Texas Basin

James M. Demarest, II, Kenneth D. Ehman

Detailed log and seismic interpretation of the Woodbine/Eagle Ford interval in the vicinity of the Hainesville dome of east Texas resulted in the recognition of salt-tectonic and eustatic controls on depositional patterns. Major cycles of transgression and regression within this interval correspond to eustatic cycles recognized worldwide. The late Cenomanian lowstand resulted in the deposition of fluvial Woodbine sandstones above the marine Maness Shale (93 Ma). Transgressive and highstand marine shales of the Eagle Ford rest above the fluvial Woodbine sands. A late Turonian sequence boundary (90 Ma) separates the highstand shales of the Eagle Ford from the lowstand and transgressive marine sands and shales of the sub-Clarksville. The section is capped by the transgressiv Austin Chalk. Between the Woodbine (93 Ma) and the sub-Clarksville (90 Ma), the Hainesville salt dome evolved from a nonpiercement to a piercement salt dome. This evolution of the Hainesville dome caused the area adjacent to the present-day dome to change from a structural high to a rapidly subsiding basin adjacent to the dome. With the rapid loss of salt into the piercement dome around 92 Ma, conditions adjacent to the dome changed from subaerial onlapping of the Woodbine fluvial facies to distal downlapping of the Eagle Ford marine shales into the center of the Hainesville withdrawal syncline. Thus, the detailed timing of salt movement is recorded in the thickness and facies distribution around the salt dome within the context of major global eustatic cycles.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990