ABSTRACT

The Upper Jurassic Norphlet Formation is an eolian sandstone and important hydrocarbon reservoir that overlies the Louann Salt in the Gulf of Mexico (GOM). Because the sand was concentrated into dunes formed by Late Jurassic winds, determining the source areas and paleotransport direction of the sand can improve predictions of the distribution of the dune facies around the GOM. Paleo–wind-blown sediment transport into the proto-GOM was controlled by wind direction and magnitude and the extant topography of the basin and adjacent uplands. Analysis of the Norphlet Formation in the eastern GOM shows that wadis and alluvial fans controlled by the location of highs were the primary route for introducing sediment of varied provenance into the eolian erg. Eolian transport directions interpreted from dip-log analyses are south directed in southern Alabama and west to northwest directed in western Florida. Interpretations of regional, two-dimensional, prestack-depth-migrated seismic data show that erosional incision of the Middle Ground arch occurred prior to and during the time of Norphlet deposition; this as well as preexisting lows in the basement topography may have facilitated basinward sand transport of sediment that fed the Norphlet Formation erg preserved in the deep-water subsurface eastern GOM.

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