Glacial fluctuations during the Last Glacial Maximum and Lateglacial in the Zhuxi and Songlong valleys, eastern Nyainqêntanglha Range, southeastern Tibet

Abstract

ABSTRACTThis study outlines the paleoglacial history and paleoclimatic conditions that were present during the Last Glacial Maximum (LGM) and Lateglacial (LG) in the Songlong and Zhuxi valleys in the eastern Nyainqêntanglha Range, southeastern Tibet. Two sets of moraines were identified at the valley mouths, and were dated using cosmogenic 10Be exposure and optically stimulated luminescence (OSL) dating. The ages suggest that two glaciations occurred at ~20–21 and ~14–16 ka, respectively, coinciding with the LGM and LG. Using glacier–climate modeling, temperature drops were calculated to have ranged from 6.3 to 7.8 °C during the LGM–LG, with precipitation being 40–60% of the present‐day value. The results in the modeled domain appear generally consistent with other climatic records from the Tibetan Plateau. Glacial advances in monsoon‐dominated southeastern Tibet during the LGM–LG were probably driven by low temperatures rather than by high precipitation, which was usually produced by an enhanced Indian Summer Monsoon during periods of climatic warming.