--> Abstract: Identification of Third-Order (Approx. 10<SUP>6</SUP> Yrs) and Fourth-Order (Approx. 10<SUP>5</SUP>/10<SUP>4</SUP> Yrs) Stratigraphic Cycles in the South Addition, West Cameron Lease Area, Louisiana Offshore, by A. Lowrie, P. Meeks, and K. Hoffman; #90950 (1996).

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Abstract: Identification of Third-Order (Approx. 106 Yrs) and Fourth-Order (Approx. 105/104 Yrs) Stratigraphic Cycles in the South Addition, West Cameron Lease Area, Louisiana Offshore

Allen Lowrie, Patricia Meeks, Karen Hoffman

In the highly explored South Addition of the West Cameron Lease Area, Louisiana offshore, interpretation of a six-mile (^approx10 km) seismic section across a single intraslope basin yielded 20 sediment packages. Several interpretive tools were necessary. Seismic stratigraphy indicated that the shallower zone was an outer shelf marked by 8 major sea level oscillations. In the portion between 1 and 3 seconds, seismic stratigraphy and paleontology led to the interpretation of depositional environments such as upper slope, and paleobathymetrically deeper intervals with descent through the section. The intraslope basin, while small, may be viewed as a micro-continental margin. Each sea level oscillation cycle apparently made a distinct progradational unit, decipherable in the seismic data. Fourth order cycles have been provisionally interpreted, throughout most of the entire 3.7 second section. Such precision is possible only in explored basins with excellent seismic data. The sequence thickness showed a seven-fold variability, from 0.08 to 0.58 seconds. The shallower section, deposited along an outer shelf, has an average individual sequence thickness of 0.13 seconds. Individual seismic sequences in the deeper section, interpreted to have been deposited on an upper slope, have average thicknesses of 0.25 seconds. The thinner sequences of the shallower section are compatible with the notion that the outer shelf was a bypass zone during a glacial epoch. The thicker sequences of the deeper section are the result of deposition onto an aggrading upper slope withi an intraslope basin during a highstand.

AAPG Search and Discovery Article #90950©1996 AAPG GCAGS 46th Annual Meeting, San Antonio, Texas