The early Last Glacial Maximum in the Gissar Range, Tajikistan, based on 10Be surface exposure dating

Roland Zech1, Ines Röhringer2, Pjotr Sosin3, Hamdam Kabgov4, Silke Merchel5, Shavkat Akhmadaliev5, Wolfgang Zech6
1 Geological Institute, ETH Zurich, Switzerland
2 Chair of Geomorphology, University of Bayreuth, Germany
3 Institute of Soil Science, Tajik Academy of Agriculture, Dushanbe, Tajikistan
4 Institute of Chemistry, Tajik Academy of Sciences, Dushanbe, Tajikistan
5 Helmholtz Zentrum, Dresden-Rossendorf, Germany
6 Institute of Soil Science and Soil Geography, University of Bayreuth, Germany

V 5.8 in Klima und Umwelt der letzten 130.000 Jahre

18.09.2012, 11:30-11:50, H6

Mountain glaciers are sensitive indicators for climate change, especially with regard to summer temperature and precipitation. Glacial chronologies from Central Asia have therefore been suggested to provide valuable information about past changes in temperature, as well as precipitation and related changes in atmospheric circulation. However, available age control is still sparse. Here we present a glacial chronology for the Gissar Range, Tajikistan, based on thirteen 10Be surface exposure ages. Prominent moraine lobes document glacial advances in phase with the global last glacial maximum (LGM) during marine isotope stage (MIS) 2. Rapid and significant deglaciation occurred already at ~20 ka as inferred from recessional stages. An older and slightly more extensive glaciation could be dated to MIS 4, whereas the timing of the most extensive glaciation remains speculative. In contrast to the glacial chronologies from the nearby, more arid Pamir and Tien Shan, where MIS 3 and MIS 5 moraines likely document past periods with increased precipitation, glaciers in the more humid Gissar Range predominantly recorded past changes in temperature and summer insolation.

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Letzte Änderung 26.07.2012