Very Large Cryoturbation Structures of Last Permafrost Maximum Age at the Foot of the Qilian Mountains (NE Tibet Plateau, China)

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• 作者：J. Vandenberghe ; X. Wang and D. Vandenberghe
• 关键词：cryoturbation ; (periglacial) loadcasting ; Last Permafrost Maximum ; NE Tibet Plateau
• 刊名：Permafrost and Periglacial Processes
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：27
• 期：1
• 页码：138-143
• 全文大小：7092K
• ISSN：1099-1530

文摘

Unusually large cryoturbation structures (4–4.5 m amplitude), developed in channel gravels and overbank fine-grained deposits of a river terrace on the NE Tibet Plateau, China, were formed by loadcasting as late Pleistocene-age permafrost degraded. It is suggested that the oversaturation and liquefaction of the thawed sediments could have been achieved only if the amount of ice in the upper 4–4.5 m of terrace sediments had been very high. The structures, dated at around 26–20 ka by OSL, point to the presence of a massive icy layer existing within a permafrost body during the Last Permafrost Maximum. Copyright