Late-Holocene dune activity linked to hydrological drought, Nebraska Sand Hills, USA

Abstract

Dunefields of the Great Plains contain stratigraphic records of episodic Holocene aeolian activity, potentially providing a valuable record of climatic change. It has been dif” cult to establish unambiguous links between activity at speci” c sites and regional palaeoclimate, however. Here we demonstrate that widespread late-Holocene aeolian activity in the Nebraska Sand Hills, the largest dune” eld on the Great Plains of North America, occurred during a period of hydrological drought. Aeolian sand sheets are interbedded with peat that accumulated in interdunes throughout much of the Holocene. The youngest of these sand sheets was deposited between 950 and 650 cal. BP, about the same time as the most recent major episode of aeolian activity at upland sites up to 120 km apart. Sand sheets could only have advanced across the interdunes if the local groundwater‘ ow systems that maintain interdune wetlands were temporarily reduced or eliminated by a reduction in recharge. Both reduced recharge and upland aeolian activity are best explained by regional megadrought.