GEOMORPHIC FORCING UPON THE WHITE RIVER BADLANDS IN THE CONTEXT OF THE MEDIEVAL CLIMATE ANOMALY, AS RECORDED BY PROXIES ACROSS THE MID-CONTINENT, NORTH AMERICA

This research has involved well over 100 undergraduate students participating in expeditions that have spanned two decades of rigorous field investigation. The goal of this study is to better understand the impacts of the Medieval Climate Anomaly (MCA) upon the Great Plains of North America. Our previous work documented an incision of slopes throughout the White River Badlands around1,000 to 1,300 AD, as dissection cut across datable paleosols, for which we possess almost three dozen radiocarbon ages. This interval coincides with the MCA (900 to 1,300 AD), which prompts us to postulate that MCA aridity in the Great Plains affected both vegetation and the landscape. To better place our findings into context, we sought proxy records of paleoclimate spanning the Rocky Mountains and Great Plains. These proxy records include paleohydrology, dune mobility, channel incision, lacustrine sediments, loess, and tree rings. If climate change triggered incision of slopes across the White River Badlands, synchronous perturbation of additional geomorphic systems would be expected. In response to this conjecture, we expanded our study to include OSL ages of dunes throughout the badlands, in order to evaluate eolian activity. We present a regional synthesis describing our understanding of slopes and dunes, in the context of mid-continental climate during this interval. Recent refinement of our field procedures, learned through surmounting myriad challenges, leaves us well poised to make significant progress during the 2017 field season.