LATE-PLEISTOCENE CLIMATE CONTROLS ON AEOLIAN ACTIVITY, CORAL PINK SAND DUNES, UTAH

This study investigates late Pleistocene climate controls on aeolian activity on the northwest Colorado Plateau. In the Coral Pink Sand Dunes, Utah, the Sevier normal fault scarp forms a topographic barrier that has trapped alluvial, fluvial, and aeolian sediments. Timing of past aeolian activity preserved in the sediment aprons will be used to understand how controls on aeolian activity have changed over glacial cycles, as well as identify changes in sediment source and wind direction.

Sediment apron stratigraphy was described in vertical exposures in channels incised through the aprons. Five aeolian deposits were identified and dated with optically stimulated luminescence (OSL). The aeolian chronology will be compared to paleoclimate reconstructions and nearby geomorphic records to test the hypothesis that aeolian activity was caused by changes in climate that resulted in either increased sediment supply or sediment availability.

Preliminary OSL results from this study record aeolian activity at the late Pleistocene-Holocene transition (OSL 12±2 ka) and during Marine Isotope Stage (MIS) 5 (OSL ~90 ka and ~100 ka). These new OSL ages provide the first evidence of aeolian activity during MIS 5 on the Colorado Plateau, and an opportunity to understand how this landscape responded to climate change during the last major interglacial period.