Abstract: Biostratigraphy of Pleistocene Depocenter: Texas-Louisiana Continental Shelf

C. Wylie Poag, Page C. Valentine

The major depocenter for Pleistocene marine sediments of the northern Gulf Coast lies beneath the outer edge of the present Texas-Louisiana continental shelf. The middle of the depocenter contains more than 3,600 m (12,000 ft) of alternating sand and shale deposits. Wells drilled in the thickest part penetrate at least seven major cycles of transgressive-regressive strata, most of which are related to eustatic changes. Nineteen new foraminiferal zones provide closely spaced correlations in facies that range from coastal-plain sands to continental slope shales. These correlations show that wells along the margin of the depocenter contain erosional unconformities that formed during regressions. Planktonic foraminifers and calcareous nannofossils define the transition betwee Pliocene and Pleistocene sediments and allow correlation with the Pleistocene stratotype in Italy and with paleomagnetically dated deep-sea cores. Detailed analyses and illustrations have been made of foraminiferal and calcareous nannofossils in the Phillips Continental Offshore Stratigraphic Test (COST) 1 well, drilled in November 1974, off Brownsville, Texas.

AAPG Search and Discovery Article #90975©1976 GCAGS- GC Section SEPM Annual Meeting Shreveport, Louisiana