Sedimentology of the Rush Springs Sandstone (Permian/Guadalupian), western Oklahoma: Evidence of an erg-erg margin depositional system.

摘要

The Rush Springs Sandstone (Permian/Guadalupian) of western Oklahoma has traditionally been interpreted as a shallow marine/fluvial-deltaic unit. Based on 23 measured sections and a 177 m core, a new model for the Rush Springs Sandstone is presented. I interpret the Rush Springs Sandstone as an ancient erg-erg margin depositional system. Based on facies relationships, the Rush Springs Sandstone can be divided into three paleoenvironmental belts in west-central Oklahoma. These belts are erg center, erg margin and extradune environments. Outcrop observations suggest that the central portion of the Rush Springs Erg was characterized by compound eolian bedforms several tens of meters high with wet/damp interdunal areas. Paleocurrent data from the Rush Springs Sandstone is in agreement with paleocurrent data from Late Paleozoic eolian sandstones in the Colorado Plateau, and indicates that regional atmospheric circulation controlled eolian deposition in western Pangea.