SEQUENCE STRATIGRAPHY OF PLIOCENE AND PLEISTOCENE TURBIDITE SYSTEMS, NORTHERN GREEN CANYON AND EWING BANK (OFFSHORE LOUISIANA), NORTHERN GULF-OF-MEXICO

Neogene turbidite systems are major reservoirs in the northern deep Gu lf of Mexico. Few publications have described the stratigraphic variat ions or the three-dimensional geometries of these turbidite systems in detail; hence, an understanding of the stratigraphic characteristics of the producing sands is important for deep-water exploration in the Gulf of Mexico and similar basins worldwide. This study focuses on the northern Green Canyon and central Ewing Bank protraction (lease) area s, where the Pliocene-Pleistocene turbidite systems were mapped using an integrated exploration database. Interpretation of 10,000 km of two -dimensional seismic, 185 well logs, and biostratigraphy from 180 well s allowed us to define the regional sequence stratigraphic framework f or this area and potential areas for future exploration. A complex Pli ocene-Pleistocene geologic evolution of the area is indicated by the s eismic and geologic facies, depositional rates, nature of turbidite sy stems, and sand content. Significant sand deposits (basin-floor fans) were deposited in most sequences and directly overlie sequence boundar ies, Salt tectonics and faulting greatly influenced the loci of these fans' deposition. Large, thick fans fill entire salt-withdrawal miniba sins at the base of the Pliocene sequences. In the Pleistocene sequenc es, where the rate of salt withdrawal was less, smaller and thinner fa ns were deposited downdip of faults and adjacent to shallow salt bodie s. Channel systems, interbedded with overbank shales, constitute most of the sediments in the sequences. The older sequences contain more ch annels and sandier channel fills than the younger sequences. Analysis of all sequences indicates a complex depositional history where signif icant sands were deposited where abrupt decreases in bathymetric gradi ent are associated with salt tectonics or faulting.