Late Pleistocene glaciers in Darhad Basin, northern Mongolia

Late Pleistocene glaciers around Darhad Basin advanced to near their maximum positions at least three times, twice during the Zyrianka glaciation (at similar to 17-19 ka and similar to 35-53 ka), and at least once earlier. The Zyrianka glaciers were smaller than their predecessors, but the equilibrium-line altitude (ELA) difference was <75 in. End moraines of the Zyrianka glaciers were similar to 1600 in asl; ELAs were 2100-2400 in asl. 14 C and luminescence dating of lake sediments confirm the existence of paleolake highstands in Darhad Basin before similar to 35 ka. Geologic evidence and Be-10 cosmic-ray exposure dating of drift suggests that at similar to 17-19 ka the basin was filled at least briefly by a glacier-dammed lake similar to 140 in deep. However, lake sediments from that time have not yet been recognized in the region. A shallower paleolake briefly occupied the basin at similar to 11 ka, but between similar to 11 and 17 ka and after similar to 10 ka the basin was probably largely dry. The timing of maximum glacier advances in Darhad appears to be approximately synchronous across northern Mongolia, but different from Siberia and western Central Asia, supporting the inference that paleoclimate in Central Asia differed among regions. (C) 2008 University of Washington. All rights reserved.