Very Large Cryoturbation Structures of Last Permafrost Maximum Age at the Foot of Qilian Mountains (NE Tibet Plateau, China): a Discussion
Intensely cold conditions occurred during part of the last major glaciation of the mountains and Qinghai–Tibet Plateau in northeast China but their chronology is constrained by few limiting ages. At the Mengyuan section, on the northeastern margin of the Qilian Mountains, sandy silt provided three O...
Published in: | Permafrost and Periglacial Processes |
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Online Access: | https://doi.org/10.1002/ppp.1942 |
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ftrepec:oai:RePEc:wly:perpro:v:28:y:2017:i:4:p:757-762 2023-05-15T16:37:30+02:00 Very Large Cryoturbation Structures of Last Permafrost Maximum Age at the Foot of Qilian Mountains (NE Tibet Plateau, China): a Discussion Stuart A. Harris Huijun Jin Ruixia He https://doi.org/10.1002/ppp.1942 unknown https://doi.org/10.1002/ppp.1942 article ftrepec https://doi.org/10.1002/ppp.1942 2020-12-04T13:31:03Z Intensely cold conditions occurred during part of the last major glaciation of the mountains and Qinghai–Tibet Plateau in northeast China but their chronology is constrained by few limiting ages. At the Mengyuan section, on the northeastern margin of the Qilian Mountains, sandy silt provided three OSL ages that suggest deposition during a very cold, dry period in northeastern China between c. 29 and 19 ka (early part of marine isotope stage (MIS) 2). Load‐casting into the underlying outwash gravel occurred during climate amelioration. In some cases, the sandy silt infilled the spaces left by underlying thawing blocks of ice without collapse of the surrounding gravel. The gravel must therefore be older than c. 30 ka and was probably deposited by outwash from glaciers on the higher parts of the Qilian Mountains during MIS 3. Included in them were buried contemporaneous or remnant blocks of glacial ice. Subsequently the surface became flat by unknown processes and was finally covered by a thin loess dating from 2.7 ka, indicating it was deposited in the first warmer period in the Neoglacial sequence of events. Thus, the last major cold event spanned the period through isotope stages 2 and 3 in this area (57 to c. 19 ka), during which the dominant effects of glaciation of the mountain tops were replaced by intensely dry, cold permafrost conditions for c. 10 ka. Copyright © 2017 John Wiley & Sons, Ltd. Article in Journal/Newspaper Ice permafrost RePEc (Research Papers in Economics) Permafrost and Periglacial Processes 28 4 757 762 |
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RePEc (Research Papers in Economics) |
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ftrepec |
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Intensely cold conditions occurred during part of the last major glaciation of the mountains and Qinghai–Tibet Plateau in northeast China but their chronology is constrained by few limiting ages. At the Mengyuan section, on the northeastern margin of the Qilian Mountains, sandy silt provided three OSL ages that suggest deposition during a very cold, dry period in northeastern China between c. 29 and 19 ka (early part of marine isotope stage (MIS) 2). Load‐casting into the underlying outwash gravel occurred during climate amelioration. In some cases, the sandy silt infilled the spaces left by underlying thawing blocks of ice without collapse of the surrounding gravel. The gravel must therefore be older than c. 30 ka and was probably deposited by outwash from glaciers on the higher parts of the Qilian Mountains during MIS 3. Included in them were buried contemporaneous or remnant blocks of glacial ice. Subsequently the surface became flat by unknown processes and was finally covered by a thin loess dating from 2.7 ka, indicating it was deposited in the first warmer period in the Neoglacial sequence of events. Thus, the last major cold event spanned the period through isotope stages 2 and 3 in this area (57 to c. 19 ka), during which the dominant effects of glaciation of the mountain tops were replaced by intensely dry, cold permafrost conditions for c. 10 ka. Copyright © 2017 John Wiley & Sons, Ltd. |
format |
Article in Journal/Newspaper |
author |
Stuart A. Harris Huijun Jin Ruixia He |
spellingShingle |
Stuart A. Harris Huijun Jin Ruixia He Very Large Cryoturbation Structures of Last Permafrost Maximum Age at the Foot of Qilian Mountains (NE Tibet Plateau, China): a Discussion |
author_facet |
Stuart A. Harris Huijun Jin Ruixia He |
author_sort |
Stuart A. Harris |
title |
Very Large Cryoturbation Structures of Last Permafrost Maximum Age at the Foot of Qilian Mountains (NE Tibet Plateau, China): a Discussion |
title_short |
Very Large Cryoturbation Structures of Last Permafrost Maximum Age at the Foot of Qilian Mountains (NE Tibet Plateau, China): a Discussion |
title_full |
Very Large Cryoturbation Structures of Last Permafrost Maximum Age at the Foot of Qilian Mountains (NE Tibet Plateau, China): a Discussion |
title_fullStr |
Very Large Cryoturbation Structures of Last Permafrost Maximum Age at the Foot of Qilian Mountains (NE Tibet Plateau, China): a Discussion |
title_full_unstemmed |
Very Large Cryoturbation Structures of Last Permafrost Maximum Age at the Foot of Qilian Mountains (NE Tibet Plateau, China): a Discussion |
title_sort |
very large cryoturbation structures of last permafrost maximum age at the foot of qilian mountains (ne tibet plateau, china): a discussion |
url |
https://doi.org/10.1002/ppp.1942 |
genre |
Ice permafrost |
genre_facet |
Ice permafrost |
op_relation |
https://doi.org/10.1002/ppp.1942 |
op_doi |
https://doi.org/10.1002/ppp.1942 |
container_title |
Permafrost and Periglacial Processes |
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28 |
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4 |
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757 |
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762 |
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1766027788586844160 |