MESOZOIC AND CENOZOIC SALT MIGRATION PATHWAYS IN OFFSHORE TEXAS, NORTHWESTERN GULF OF MEXICO
Published:December 01, 1993
BARRY E. BRADSHAW, JOEL S. WATKINS, 1993. "MESOZOIC AND CENOZOIC SALT MIGRATION PATHWAYS IN OFFSHORE TEXAS, NORTHWESTERN GULF OF MEXICO", Salt, Sediment and Hydrocarbons, Adam’s Mark Hotel
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Interpretation of seismic data in the northwestern Gulf of Mexico reveals complex migration pathways of Louann Salt. The salt was originally deposited in Jurassic salt basins distributed checkerboard-fashion across rifted basement. These basins were segmented along strike by northwest-southeast trending strike slip (transfer) faults. During a period of low sedimentation in the Late Cretaceous and Paleogene, salt migrated vertically out of the basins via feeder stocks into regionally coalescing allochthonous canopies. Contemporary evidence of the mother salt layer consists of salt rollers and salt domes rooting at depths of 7,400-10,700 m.
Migration of salt into canopies was probably driven by depositional loading and gravity spreading. The migration began during deposition of Mesozoic carbonates and siliciclastics and continued through the Paleogene. Basins and canopies appear to have been offset systematically to the southeast across the transfer faults.
From Late Oligocene through Late Miocene, large delta systems prograded over the salt canopies. The prograding wedges created pressure gradients that squeezed salt seaward and out of the canopies. The salt then rose to a level near the sea floor where it spread laterally into allochthonous sheets. Loading and spreading combined to displace salt over 100 km onto the Sigsbee slope. Seaward migration of salt created extensive salt withdrawal and basins. Large, laterally continuous growth fault systems bound most basins on their landward margins. Thicknesses of sedimentary units may expand several fold across these faults. Remnants of salt canopies are locally evident in seismic data.