Abstract: Sequence Stratigraphy and Structure of Plio-Pleistocene Sediments in Northeast Gulf of Mexico--An Example of Continental Slope Sedimentation

Abu N. Chowdhury, Robert E. Sheriff, DeWitt C. Van Siclen

Sequence stratigraphic analyses and structural mapping on a series of sequence boundaries in a 20 sq. mile area on the continental slope of the northeastern Gulf of Mexico, approximately 100 miles southeast of New Orleans, reveal the depositional history of Plio-Pleistocene sediments. The integration and iterative interpretation of a dense grid of high-resolution seismic, a regional seismic grid, well log, and biostratigraphic data led to mapping seven sequence boundaries within the Plio-Lower Pleistocene sediments and establishing the chronostratigraphic framework of the area. The slope-fan systems tracts of the Pliocene sequences are characterized by prominent channel-levee facies. These facies, combined with the isochron maps of the slope-fan systems tract, indicate paleodeposition l pathways. A very high sedimentation rate in the Middle Pliocene and switching of depocenters indicated by the sequence-isochron maps suggest contemporaneous southeastward salt movement and generation of a new NW-SE fault system that show a right angle relationship with an older down-to-the-basin fault system. Migration of hydrocarbons probably occurred during this period of structural instability. Lower Pleistocene strata are very thin, reflecting much slower deposition in the lower slope-fan environment.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994