Spatial and temporal patterns of late Quaternary eolian deposition, eastern Colorado, USA

Three sand units are recognized on the basis of bedforms, topographic expression, and soil development. Preliminary age limits for the three units, based on 26 numerical ages, are 22.5-9 ka, 8-1 ka, and 1.0-0.15 ka. The middle unit is the product of multiple episodes of eolian activity that are not yet accurately dated. Loess is widespread but thin (generally < 2.4 m). Three units - middle Pleistocene, late Pleistocene, and Holocene - are recognized on the basis of differences in soil-profile development and stratigraphic position. -from Author