Abstract

The sandstones and siltstones which dominate the mid-Permian in the Delaware Basin (Texas, New Mexico) are reinterpreted by comparison with the Pleistocene eolo-marine sediments off the Saharan west coast. We suggest that the separation of sands and silts occurred during eolian transport across deserts. Dust was directly contributed to the basin by fallout, yielding topography-mantling, laminated sandy siltstones. Dunes reached the shelf break during a low sea-level stand (peak glaciation) and gave rise to turbidites that deposited the massive channel sands of Brushy Canyon time. Subsequently (Cherry Canyon and Bell Canyon times), dune sands and eolian silts were blended on the platform before aqueous delivery to the shelf break, to yield silty and micaceous channel sands and overbank turbidites interbedded with eolo-marine silt beds. The black-white laminated eolo-marine silstones may record seasonal fluctuations in organic productivity related to the dustborne nutrient supply and to upwelling in a strong seasonal wind regime such as that recorded in the Sahara.

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