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Palaeoglaciology of Bayan Har Shan, NE Tibetan Plateau: exposure ages reveal a missing LGM expansion

Author:
  • Jakob Heyman
  • Arjen P. Stroeven
  • Marc W. Caffee
  • Clas Hattestrand
  • Jonathan M. Harbor
  • Yingkui Li
  • Helena Alexanderson
  • Liping Zhou
  • Alun Hubbard
Publishing year: 2011
Language: English
Pages: 1988-2001
Publication/Series: Quaternary Science Reviews
Volume: 30
Issue: 15-16
Document type: Journal article
Publisher: Elsevier

Abstract english

The Bayan Har Shan, a prominent upland area in the northeastern sector of the Tibetan Plateau, hosts an extensive glacial geological record. To reconstruct its palaeoglaciology we have determined Be-10 exposure ages based on 67 samples from boulders, surface pebbles, and sediment sections in conjunction with studies of the glacial geology (remote sensing and field studies) and numerical glacier modelling. Exposure ages from moraines and glacial sediments in Bayan Har Shan range from 3 ka to 129 ka, with a large disparity in exposure ages for individual sites and within the recognised four morphostratigraphical groups. The exposure age disparity cannot be explained by differences in inheritance without using unrealistic assumptions but it can be explained by differences in post-depositional shielding which produces exposure ages younger than the deglaciation age. We present a palaeoglaciological time-slice reconstruction in which the most restricted glaciation, with glaciers less than 10 km long, occurred before 40-65 ka. More extensive glaciations occurred before 60-100 ka and 95-165 ka. Maximum glaciation is poorly constrained but probably even older. The Bayan Hat Shan exposure age dataset indicates that glaciers on the northeastern Tibetan Plateau have remained surprisingly restricted for at least 40 ka, including the global last glacial maximum (LGM). This case of a missing LGM is further supported by high-resolution glacier modelling experiments. (C) 2011 Elsevier Ltd. All rights reserved.

Keywords

  • Geology
  • Tibetan plateau
  • Palaeoglaciology
  • Bayan Har
  • Exposure dating

Other

Published
  • ISSN: 0277-3791
Helena Alexandersson
E-mail: helena [dot] alexanderson [at] geol [dot] lu [dot] se

Professor

Quaternary Sciences

+46 46 222 44 83

435

16

Aeolian sand project

Project members
Members of the aeolian sand project: Martin Bernhardson, Sara Florén, Edyta Kalińska-Nartiša and Helena Alexanderson.

Read more about the project here.