The timing and cause of glacial activity during the last glacial in central Tibet based on 10Be surface exposure dating east of Mount Jaggang, the Xainza range

Mountain glaciers are sensitive to climate change, and can provide valuable information for inferring former climates on the Tibetan Plateau (TP). The increasing glacial chronologies indicate that the timing of the local Last Glacial Maximum (LGM) recorded across the TP is asynchronous, implying different local influences of the mid-latitude westerlies and Asian Summer Monsoon in triggering glacier advances. However, the well-dated sites are still too few, especially in the transition zone between regions controlled by the two climate systems. Here we present detailed last glacial chronologies for the Mount Jaggang area, in the Xainza range, central Tibet, with forty-three apparent Be-10 exposure-ages ranging from 12.4 +/- 0.8 ka to 61.9 +/- 3.8 ka. These exposure-ages indicate that at least seven glacial episodes occurred during the last glacial cycle east of Mount Jaggang. These include: a local LGM that occurred at similar to 61.9 +/- 3.8 ka, possibly corresponding to Marine Isotope Stage 4 (MIS 4); subsequent glacial advances at similar to 43.2 +/- 2.6 ka and similar to 35.1 +/- 2.1 ka during MIS 3; one glacial re-advance/standstill at MIS3/2 transition (similar to 29.8 +/- 1.8 ka); and three glacial re-advances/standstills that occurred following MIS 3 at similar to 27.9 +/- 1.7 ka, similar to 21.8 +/- 13 ka, and similar to 15.1 +/- 0.9 ka. The timing of these glacial activities is roughly in agreement with North Atlantic millennial-scale climate oscillations (Heinrich events), suggesting the potential correlations between these abrupt climate changes and glacial fluctuations in the Mount Jaggang area. The successively reduced glacial extent might have resulted from an overall decrease in Asian Summer Monsoon intensity over this timeframe. (C) 2018 Elsevier Ltd. All rights reserved.