T188 Eolian Processes and Landscape Evolution (Posters)

Tuesday, 24 September 2019
9:00 AM - 6:30 PM
Hall AB, North Building

USING AN INTEGRATED SURFICIAL AND SUBSURFACE APPROACH TO UNDERSTAND PERIODS OF ACTIVITY IN THE DUNES OF SOUTHERN BOUQUET TABLE, WHITE RIVER BADLANDS SOUTH DAKOTA, USA

Paper number: T188-8
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

Aeolian systems provide insight into changes in local and regional climate. Periods of activity generally correlate to times of increased aridity and/or landscape and vegetation destabilization. Understanding the timing and intensity of aeolian activity improves reconstruction of regional and local climatic impacts. The White River Badlands (WRB) aeolian dunes are located on the western section of the northern Great Plains in southwestern South Dakota. Vegetation stabilized aeolian deposits, including parabolic dunes and sand sheets, are found on mesas known locally as tables. On Bouquet Table (BT), previous work has identified a complex of dune forms that have been episodically active during the Holocene. Dates of activity are constrained through previously-reported Optically Stimulated Luminescence dating (OSL) and suggest stabilization ages that range from modern to ~11 kya.

A small subset of eastern BT was surveyed using high-resolution, UAV-based photogrammetry and ground penetrating radar (GPR). UAV-based imagery was used to create digital elevation models and orthophoto mosaics while the GPR for imaging the subsurface architecture of dune systems. GPR surveys were primarily acquired along the axes of blowouts and parabolic features, as well as crossing locations of previously reported OSL samples. The integration of previous work with the new subsurface GPR facies models, including paleosol interpretations, with surficial morphology using orthophotos and 3D models is designed to provide a more comprehensive geomorphic and palaeogeographic reconstruction. Early results suggest a complex vertical and shingled relationship exists between landforms with younger dunes climbing over older dune forms progressively to the southeast.

While data analysis and integration are ongoing, early outcomes show promising results. A complete analysis of surficial morphology and subsurface architecture will provide a palaeogeographic reconstruction of the dune field at times of stabilization that can be correlated to OSL absolute ages. Ultimately, this approach will be extrapolated from BT to surrounding tables in the WRB in an effort to elucidate the relationships between aeolian activity, climate, and local forcings.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-339590

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