TURBIDITE SYSTEMS AND THEIR TEMPORAL AND SPATIAL DISTRIBUTION, DEEP GULF OF MEXICO BASIN

Abstract

ABSTRACT A detailed seismic stratigraphic analysis of the deep Gulf of Mexico basin allows the subdivision of post mid-Cretaceous deep water clastic sediments into eighteen seismic sequences. Each sequence consists mainly of lowstand systems tracts bounded by regional correlative conformities, which are characterized by regionally extensive, continuous, high-amplitude reflections. A chronostratigraphic framework for the eighteen seismic sequences has been established by using seismic and well data. Seismic facies analysis allows the identification of fifteen seismic facies and reveals diverse turbidite systems, suggesting equally diverse depositional processes operating in the deep Gulf of Mexico basin. Each sequence consists of several submarine fans, which were deposited along the margins of the deep basin and characterized by various turbidite systems, including sand-rich turbidite/lobe complexes, sand-rich mounded turbidite/lobe complexes, unchannelized turbidite systems, partially channelized turbidite systems, and channel/levee/overbank turbidite systems. Basinal low energy mud-rich turbidites and hemipelagic/pelagic sediments dominate the rest of the deep basin. The vertical occurrence of seismic facies reflects the progradational infill of the deep basin by submarine fans through time, as indicated by the successive appearance of unchannelized, partially channelized, and channel/levee/overbank turbidites systems. The spatial distribution of submarine fan systems is closely related to the shifting in position of time equivalent shelf margin depocenters, suggesting the existence of sediment fairways across the continental slope.