Isotope Chronostratigraphy of South Timbalier 198; Relationship of Paleo Sea-Level and Sediment Deposition

TRAINOR, D. M., and D. F. WILLIAMS, University of South Carolina, Columbia, SC

A high resolution geochronology is possible in Plio-Pleistocene sediments of the outer continental shelf-slope of the Gulf of Mexico using isotope chronostratigraphy. _O data from OCS well G-1267 Number A-1 from South Timbalier block 198 when integrated with the biostratigraphy enables the definition of 47 isotope stages in the Plio-Pleistocene section of the well. This oxygen isotope record is utilized to (1) refine the overall chronostratigraphy, (2) provide detailed

information relating to sediment accumulation rate changes, (3) compare the electric log data to the paleo sea-level record, and (4) relate the site-specific paleo sea-level record to the seismic section by converting the isotope record to travel time. O(18) stages 24-27 and 48-60 are separated by a hiatus from 0.9-1.41 Ma. O(18) stages 60-104 are missing due to a hiatus from 1.75-3.15 Ma. O(18) stages 104-133 are defined in the lower section of the well. The sedimentation is broken into three packages by two unconformities with sedimentation rates fluctuating from 33-2.4 ft/Ka. Comparing the resistivity and SP logs to the paleo sea-level record, 65% of the defined sand units are associated with lowstands or transgressions. Seismic sequence boundaries and depositional models derived f om the seismic sequence stratigraphy are directly compared to the paleo sea-level record from this South Tambalier 198 well site.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)