158 D29. Quaternary Geology II

Wednesday, 28 October 2020
5:30 PM - 8:00 PM
Meeting Rooms

LATEST HOLOCENE AEOLIAN ACTIVITY IN THE WHITE RIVER BADLANDS DUNE FIELDS, SOUTH DAKOTA, NORTHERN GREAT PLAINS, USA

Paper number: 158-7
Program: Technical Sessions
Time: 6:25 PM – 6:35 PM

Authors

Abstract

Preserved aeolian landscapes provide insight into the intensity and regional extent of drought events, as well as wind direction. The White River Badlands (WRB) dune field, a relatively small dune field located in southwestern South Dakota, 60 km upwind of the western Nebraska Sand Hills, is one of the northernmost dune fields in the western Great Plains. Understanding the timing of aeolian activity in the WRB is critical to distinguishing local versus regional and global climate forcing events, as well as determining provenance of midcontental sand and loess on the central Great Plains.

Previous work constructed a chronology of WRB aeolian activity using 37 optically stimulated luminescence (OSL) ages of samples collected throughout the WRB. OSL ages support three periods of aeolian activity that stabilize at 21.0 to 12.4 ka, 9.2 to 6.1 ka, and 720 to 210 a. OSL ages also support that dune forms from these periods are preserved, providing evidence of dominant wind direction throughout the Holocene.

This presentation includes a new dataset of high-resolution drone imagery to support interpretations of timing aeolian activity and paleo wind direction. Interpretation of high-resolution digital elevation models (DEMs) supports the following observations 1) low-relief and attenuated dunes and blowouts formed in the early to middle Holocene and were not reactivated by subsequent aeolian events, 2) no evidence of Medieval Climate Anomaly aeolian activity was found but significant aeolian activity occurred during the Little Ice Age, and 3) dominant NW wind direction in the WRB, as recorded in dune forms and blowouts, has changed little from the early Holocene to present. Taken together, the OSL chronology and the DEMs can be used to plan future investigations in the WRB to find 1) preserved older sand that records the timing of the initiation of the three periods of aeolian activity, and 2) evidence for reactivation during the Medieval Climate Anomaly.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-355516

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