Pleistocene Deposition and Structure: Galveston South OCS, Offshore Texas

S. E. Brooks, J. S. Watkins

Mapping of four Pleistocene sequences in the Galveston South and northern East Breaks areas shows three depopods containing over 1,000 m of sediment. Depopods A, B, and C are located in (A) East Breaks Block 108, (B) Galveston South Blocks 244-245, and (C) Galveston South Blocks 219-220. Depopod A shifts slightly landward with time because of salt withdrawal. The later position of the depopod coincides with the shelf break for that unit as indicated by sigmoidal progradation. The other two depopods shift slightly basinward and are centered on faults with rollover. All depopods contain hydrocarbon indicators.

Faults dominate the southern portion of the region. The faults cut the present shelf edge at 30°, suggesting that the Pleistocene shelf edge lay roughly 30° to the present one. Salt diapirs evident in the southern part of the area formed because of sediment loading at the shelf edge. The diapirism dies out northward on the shelf.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.