Title

Cosmogenic Be-10 Surface Exposure Dating and Glacier Reconstruction for the Last Glacial Maximum in the Quemuqu Valley, Western Nyainqentanglha Mountains, South Tibet

Authors

Dong, GC;Xu, XK;Zhou, WJ; Fu, YC ;Zhang, L;Li, M

Abstract

The nature and timing of glaciations enable inferences to be made about glacial climates. However, the paucity of reliable glacial chronologies impedes a full understanding of the Last Glacial Maximum (LGM) climate in the western Nyainqentanglha Mountains, south Tibet. In this study, we investigated the LGM glacial history in the Quemuqu Valley, western Nyainqentanglha, using Be-10 surface exposure dating. We used a physically based glacier model to reconstruct the LGM glacial surfaces, and estimated the LGM equilibrium-line-altitude (ELA) using integrated methods. Combined with previously published Be-10 exposure ages from the western Nyainqentanglha, ten Be-10 exposure ages imply a relatively restricted glacial extent in the LGM but extensive growth in the early last glacial. The modeled LGM glaciers had ice areas of approximate to 36.3km(2), 3.21km(3) in volume and 89mm in average thickness in the Quemuqu Valley. The reconstructed LGM ELAs have values of 5463-5583masl, with a depression of approximate to 244-364m. By combining the reconstructed ELAs with an equation deduced from glacier mass balance, we concluded that the temperature dropped by approximate to 2.6-4.6 degrees C in the LGM relative to the present, with 30-70% lower precipitation than the present. Global cooling induced the LGM glacial advance in the western Nyainqentanglha despite decreased precipitation.

Corresponding author

Dong Guocheng，Xu Xiangke

Volume

32

Issue

5

Page

639-652

Pub year

2017

Publication name

JOURNAL OF QUATERNARY SCIENCE

Details

http://onlinelibrary.wiley.com/doi/10.1002/jqs.2963/abstract