Mapping and Spatial Analysis of Aeolian Deposits, White River Badlands, South Dakota

The goal of this study is to determine the timing of the latest episode of aeolian dune activity in the White River Badlands (WRB) south of the North Unit of the Badlands National Park (BNP), South Dakota. Our previous results indicate that alluvial pediments in the BNP experienced an episode of fluvial incision initiated by approximately 1,000 AD. We hypothesize that incision was caused by a regional drought that destabilized pediment surfaces and enhanced erosive power of periodic storms sometime in the interval known as the Medieval Climatic Anomaly (approximately 900 to 1200 AD). We further hypothesized that a regional drought would have driven change in other geomorphic systems in the WRB. WRB aeolian dune fields occur north of the White River on approximately 400 km2 of dissected strath terraces. Aeolian features include aeolian cliff-top deposits (ACT), sand sheets, and stabilized parabolic dunes. Previous 14C analyses of paleosols indicated that ACT accumulated rapidly post 1300 radiocarbon years before present (Rawlings et al., 2003), approximately the same time as pediment incision in BNP. Further study of these aeolian deposits could determine whether a regional drought occurred in the WRB and shed light on climate changes on the northern Great Plains. In summer 2014, we made a reconnaissance trip the WRB dune fields in preparation for more detailed study. We are using digital mapping technology and remote sensing analysis to map dune forms on strath terraces in the WRB. Surficial maps will be used to establish cross-cutting relationships and relative ages of WRB dune forms, as well as wind direction. GIS 3D technology was used to convert digital elevation models to triangulated irregular networks (TIN) for analysis. Remote sensing analysis was accomplished using SPOT 5 imagery of the dune complex classified using Principle Component Analysis (PCA) and an unsupervised classification. Investigators will discuss results of the summer 2014 WRB reconnaissance and subsequent digital mapping and remote sensing analysis of the White River dune fields