NEW AGES OF DUNE ACTIVITY DURING AND FOLLOWING THE MEDIEVAL CLIMATIC ANOMALY ON THE EASTERN MARGIN OF THE GREAT PLAINS

Great Plains dune fields have provided much insight into the history of Holocene megadroughts—geographically extensive droughts much more severe than historic droughts such as the 1930s dust bowl. To date, most research has emphasized the timing of these droughts as expressed in activation chronologies of large central Great Plains dune fields. Recent research however, has explored the smaller dune fields along the eastern periphery of the Great Plains, not only to refine timing, but also to determine the geographical extent of these megadroughts. This study is the third in a series of ongoing studies of small peripheral dune fields along the eastern margin of the Great Plains that aim to determine the eastward extent of late Holocene megadroughts. The Hutchinson dune field is a 400 km², southeast-northwest oriented field, which mantles a Pleistocene high terrace (~60-90 ka) on the north side of the Arkansas River valley. Dating of the dune sand, via luminescence, has produced an activation chronology beginning about 1.0 ka and extending to 0.07 ka. While some activation occurred during the Medieval Climatic Anomaly (MCA), the majority occurred at and following its termination (~0.4-0.2 ka). These ages of dune activity, in concert with activity ages from other eastern-margin dune fields, suggest that geographically-extensive drought was prevalent throughout the Great Plains well after the MCA, up until only a few hundred years ago.