Typical Soft–Sediment Deformation Structures Induced by Freeze/Thaw Cycles: A Case Study of Quaternary Alluvial Deposits in the Northern Qiangtang Basin, Tibetan Plateau
Author:
Affiliation:

Clc Number:

Fund Project:

During this study, the authors carefully read the book “Soft sedimentary deformation structures-earthquake and ancient earthquake records” by Qiao Xiufu et al., 2017, which has greatly helped us to understand, assess and interpret the soft sedimentary deformation structures in the area. We thank Drs. Qiao Xiufu, Su Dechen, Pan Jiawei, He Xiangli and Chen Andong for their fruitful discussion. We are also grateful A.J. (Tom) Van Loon for valuable suggestions and the English improvement. This work is supported by projects from the National Natural Science Foundation of China (41807298, 41702372, 41672211), the China Postdoctoral Science Foundation (2019M650788), National Key Research and Development Project of China (2016YFC0600310), the China Geological Survey (DD20160022, DD20190059), and the Basic Research Funds (JYYWF201810) of the Institute of Geology, CAGS.

  • Article
  • |
  • Figures
  • |
  • Metrics
  • |
  • Reference
  • |
  • Related
  • |
  • Cited by
  • |
  • Materials
  • |
  • Comments
    Abstract:

    With the objective of establishing a distinction between deformation structures caused by freeze/thaw cycles and those resulting from seismic activity, we studied three well–exposed alluvial deposits in a section at Dogai Coring, northern Qiangtang Basin, Tibetan Plateau. Deformation is present in the form of plastic structures (diapirs, folds and clastic dykes), brittle structures (micro–faults) and cryogenic wedges. These soft–sediment deformation features (except the micro–faults) are mainly characterized by meter–scale, non–interlayered, low–speed and low–pressure displacements within soft sediments, most commonly in the form of plastic deformation. Taking into account the geographic setting, lithology and deformation features, we interpret these soft–sediment deformation features as the products of freeze/thaw cycles, rather than of earthquake–induced shock waves, thus reflecting regional temperature changes and fluctuations of hydrothermal conditions in the uppermost sediments. The micro–faults (close to linear hot springs) are ascribed to regional fault activity; however, we were unable to identify the nature of the micro–faults, perhaps due to disturbance by subsequent freeze/thaw cycles. This study may serve as a guide to recognizing the differences between deformation structures attributed to freeze/thaw cycles and seismic processes.

    Reference
    Related
    Cited by
Get Citation

ZHONG Ning, LI Haibing, JIANG Hanchao, LU Haijian, ZHENG Yong, HAN Shuai, YE Jiachan.2020. Typical Soft–Sediment Deformation Structures Induced by Freeze/Thaw Cycles: A Case Study of Quaternary Alluvial Deposits in the Northern Qiangtang Basin, Tibetan Plateau[J]. Acta Geologica Sinica(),94(1):176-188

Copy
Share
Article Metrics
  • Abstract:
  • PDF:
  • HTML:
  • Cited by:
History
  • Received:February 11,2019
  • Revised:December 20,2019
  • Adopted:
  • Online: March 03,2020
  • Published: