Sequence Stratigraphy of Upper Miocene to Pleistocene Sediments of the Central Mississippi Canyon and Northern Atwater Valley Areas, Northern Gulf of Mexico

Hector Gonzalez, Paul Weimer, Renaud Bouroullec, and R. Jay Austin
University of Colorado, Boulder, CO

Regional 2-dimensional seismic and well data were used to establish the sequence stratigraphic and structural framework of the central Mississippi Canyon and northern Atwater Valley protraction areas, northern Gulf of Mexico. The slope consists of a complex of allochthonous salt deposits including, one called the Rum Roho, two isolated salt stocks, and the Sigsbee salt nappe. Three deep intra-slope minibasins and one suprasalt minibasin characterize the depositional setting. The bulk of Oligocene-Pleistocene sediments that filled these minibasins are primarily turbidites comprised of sheet sands, channel-levee complexes, and overbank deposits that were sourced from the Mississippi delta system.

Twelve depositional sequences were recognized and correlated in the study area, lying between 13.05 and 1.3 Ma. Based on seismic facies analysis and well-log interpretation, the vertical succession of sediments ranging from the mid-Oligocene to late Miocene was interpreted as deposited primarily during periods of low standing sea level.

The study area includes seven petroleum fields or discoveries. Several additional undrilled prospects are present. Growth faults and turtle structures, associated with the extensional regime, formed during salt withdrawal and constitute the petroleum traps. Salt mobilization controls the geometry and thickness of the different depositional units, and creates the structural seal for petroleum entrapment.

AAPG Search and Discovery Article #90032©2004 GCAGS 54th Annual Convention, San Antonio, Texas, October 10-12, 2004