INTERACTIONS BETWEEN SALT TECTONICS AND SEDIMENTATION IN THE LOUISIANA OFFSHORE: PRELIMINARY RESULTS
Published:December 01, 1993
MARK G. ROWAN, PAUL WEIMER, BARRY C. MCBRIDE, PETER VARNAI, ZURILMA ACOSTA, FADJAR BUDHIJANTO, RAFAEL MARTINEZ, ALONSO NAVARRO, TOMAS VILLAMIL, J. CARL FIDUK, 1993. "INTERACTIONS BETWEEN SALT TECTONICS AND SEDIMENTATION IN THE LOUISIANA OFFSHORE: PRELIMINARY RESULTS", Salt, Sediment and Hydrocarbons, Adam’s Mark Hotel
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Seismic profiles, well logs, biostratigraphic data, and cross section restorations were integrated to investigate the relationships between salt tectonics and sedimentation in northern Green Canyon, Ewing Bank, and southwestern Eugene Island. Preliminary results address three aspects of salt-sediment interaction.
First, minibasins have characteristic stratigraphic stacking patterns that evolve from ponded to bypass settings. The transition may occur entirely within the slope environment or be associated with shelf progradation through the minibasin. The shift can sometimes be related to salt evacuation, and in other cases to regional variations in the location and volume of clastic input.
Second, different types of salt bodies have varying bathymetric expressions that may affect sequence thicknesses and facies development: reactive diapirs are overlain by graben at the sea floor; passive diapirs usually create asymmetric highs, with smooth slopes on some flanks and steep scarps on others; and diapirs modified by contraction are marked by broad topographic highs.
Third, models of salt sheet emplacement by extrusion at the sea floor have important implications for the spatial and temporal shifting of sedimentation patterns. Salt bodies originally covered by condensed sections become major minibasins, while bathymetric lows that serve as turbidite conduits and depocenters may be overridden by allochthonous salt sheets.
Because complex salt/sediment geometries in any area are genetically linked to surrounding basins and salt bodies, the interactions between deformation and sedimentation can be understood only by reconstructing the regional evolution of both salt and sediments. Although a daunting task, such efforts will aid in the exploration for hydrocarbons, especially in the sub-salt province.