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The AAPG/Datapages Combined Publications Database

Houston Geological Society Bulletin

Abstract


Houston Geological Society Bulletin, Volume 35, No. 9, May 1993. Pages 6-6.

Abstract: Cenozoic Structural Evolution and Tectono-Stratigraphic Framework of the Northern Gulf Coast Continental Margin

By

Fred A. Diegel

Structural evolution of the northern Gulf Coast is controlled by progradation over deforming, largely allochthonous, salt structures derived from a Jurassic salt section. The variety of structural styles is due to a range of Mesozoic salt structures, a variety of slope depositional styles, and the degree of salt withdrawal. Non-genetic tectono-stratigraphic provinces describe regions of contrasting structural styles. Provinces include 1) autochthonous salt provinces around the salt basin margins, 2) detachment fault provinces onshore and on the shelf, 3) fault-bounded mini-basin/ peripheral salt provinces, 4) tabular salt provinces on the continental slope, and 5) fold and thrust provinces at the base of the continental slope. Shale-based detachment systems, dominated by lateral extension, and allochthonous salt-based detachment systems, dominated by subsidence, can be distinguished by geometry, reconstruction, and subsidence analysis. Many shale-based detachments are linked to deeper salt-based detachments. Large extensions above detachments are Previous HitbalancedTop by salt withdrawal. Salt withdrawal mini-basins with associated salt bodies occur as isolated structural systems and as a component of salt-based detachment systems. With progressive salt withdrawal during progradation, mini-basins evolve from slope basins above tabular salt to shelf basins bounded by arcuate growth faults. Associated salt bodies evolve from pillows, ridges, and massifs to leaning domes and steep-sided stocks. Allochthonous salt spreads from inclined salt bodies that appear as feeder faults when collapsed. Coalesced salt tongues from multiple feeders form canopies which provide subsidence potential for further cycles of salt withdrawal. The Sigsbee Escarpment is the expression of salt flows overriding the abyssal plain tens of kilometers since the Paleogene. The distribution and reconstruction of Oligo-Miocene salt-based detachments and mini-basins implies that a Paleogene salt canopy, covering large areas of the present onshore and shelf, may have extended as far as the Sigsbee salt mass.

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