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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 55 (1971)

Issue: 2. (February)

First Page: 369

Last Page: 370

Title: Plio-Pleistocene Geology, Outer Continental Shelf, Louisiana and Texas: ABSTRACT

Author(s): H. O. Woodbury, I. B. Murray, Jr., W. H. Akers, P. J. Pickford

Article Type: Meeting abstract

Abstract:

Pliocene and Pleistocene deposition on the outer continental shelf and upper continental slope offshore from Louisiana and Texas was a continuation of the process of prograding deltaic sedimentation with associated hydrocarbon accumulation that has been active in the northern Gulf of Mexico since the end of the Cretaceous. However, this more recent phase of the geologic history of the northern Gulf of Mexico basin differs from the earlier Tertiary history of the area in several significant aspects.

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1. The rate of sediment deposition was high. The Plio-Pleistocene embraced only 5 m.y., whereas the Miocene lasted 17 m.y., and the Oligocene and Eocene 32 m.y., yet the volume of sediment deposited during each epoch is comparable.

2. The center of deposition moved northeastward, from South Texas in the Eocene to southeastern Louisiana in the late Miocene-early Pliocene, and then shifted westward again in the Pleistocene. This shifting in depocenters was accompanied by a progradation of the continental shelf edge to its present position near the 600 ft isobath. Hydrocarbon productive trends follow these shifting depocenters.

3. Most of the Plio-Pleistocene sediment was deposited upon substrata which included several thousand feet of mobile salt plus a comparable thickness of mobile, deep water prodeltaic clay. The weight of the accumulating sediments has caused movement of the underlying mobile material so that today the structural condition of the strata in the Plio-Pleistocene depocenters is complicated by numerous large piercement salt domes and ridges, by domes and ridges of diapiric shale, and by many normal faults with displacements up to thousands of feet with omnidirectional strike and dip.

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