Very large cryoturbation structures of Last Permafrost Maximum age at the foot of the Qilian Mountains (NE Tibet Plateau, China)

• Published in: Permafrost and Periglacial Processes
• Main Authors: Vandenberghe, J.F., Wang, X., Vandenberghe, D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Ice; permafrost; Permafrost and Periglacial Processes
• Online Access: https://research.vu.nl/en/publications/c608e192-4971-450a-8b4f-3cfd76f2afb8; https://doi.org/10.1002/ppp.1847; http://hdl.handle.net/1871.1/c608e192-4971-450a-8b4f-3cfd76f2afb8

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.