Identification of a - 15 m middle Wisconsin shoreline on the Texas inner continental shelf

The maximum sea level position during the middle Wisconsin (oxygen isotope stage 3) is controversial, it being interpreted as anywhere from at or abov e present-day levels to -85 m. High-resolution seismic, lithologic, paleont ologic, and radiocarbon data from the east Texas continental shelf were use d to map a stage 3 shoreline. The shoreline was placed in a regional contex t with a study of the Texas shelf, based on seismic profiles, core, and pla tform boring descriptions, that identifies the stage 3 maximum flooding sur face and the stage 2 sequence boundary. These surfaces were then traced up- dip on the east Texas shelf where a shore parallel escarpment was recognize d. Landward of the escarpment the stage 3 maximum flooding surface is amalg amated with the stage 2 sequence boundary. Therefore, the location of the e scarpment marks the up-dip limit of stage 3 deposits and a stage 3 shorelin e. Lagoonal sediments with in situ brackish water fossils on-lap the escarp ment. Seaward of the escarpment, remnants of barrier island facies have bee n preserved as a bank, Freeport Rocks Bathymetric High, located in -18 m of water. The shoreline (adjusted for subsidence) is located at -15 +/- 2 m, which is shallower than what oxygen isotope and coral records indicate. (C) 2000 Elsevier Science B.V. All rights reserved.