Xinjiang, China): the Case of the Hotan Anticline

Xinjiang, China): the Case of the Hotan Anticline

EGU21-7443 https://doi.org/10.5194/egusphere-egu21-7443 EGU General Assembly 2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Kinematics of Cenozoic shortening across the foothills of the Western Kunlun Range (Xinjiang, China): the case of the Hotan anticline Guillaume Baby1, Martine Simoes1, Laurie Barrier1, Christelle Guilbaud1, Jérôme Van der Woerd2, and Haibing Li3 1Université de Paris, Institut de physique du globe de Paris, CNRS, F-75005, Paris, France 2Institut de physique du globe de Strasbourg, Université de Strasbourg, CNRS, UMR 7516, Strasbourg, France 3Institute of Geology, Chinese Academy of Geological Sciences, Beijing, China Quantitative constraints on the Cenozoic deformation of the northwestern edge of the Tibetan Plateau remain limited, in particular in terms of shortening rates and of their possible evolution over time. This is indeed the case for the Western Kunlun Range, along the southwestern rim of the Tarim Basin, even though surface geological data and an extensive database of seismic profiles allow to explore the sedimentary record of Cenozoic deformation. Here, we take advantage of these data to document the structural geometry and Cenozoic kinematics of the large scale east-west striking Hotan anticline along the mountain front. Four balanced cross- sections are constructed, and the temporal evolution of deformation is deciphered from the exceptionally seismically well imaged growth strata on the forelimb of the anticline. The fold results from a broad unfaulted basement ramp anticline, subsequently deformed by a duplex structure that developed in the footwall units. The total shortening of the Hotan thrust system is relatively constant along strike, from ~40 to ~32 km. The shortening accommodated by the duplex varies laterally from west to east, from ~50-40 % to 0 % of the total shortening. Two distinct successive patterns of growth strata are recognised in the forelimb, and are interpreted to be representative of deformation on the basement ramp, followed by deformation related to the growth of the underlying duplex. Deformation on the basement ramp initiated by ~17 Ma, when calibrating growth seismic reflectors on surface magnetostratigraphic sections. Deformation of the underlying duplex began at ~12 Ma to the west and subsequently propagated eastward. From these results on shortening and timing of deformation, we determine a shortening rate of 4-3 mm/yr from ~17 to ~7 Ma across the Hotan anticline. We find a significant subsequent decrease in shortening rates, possibly down to <0.5 mm/yr since the uppermost Miocene. These rates are compared to existing values and their regional significance is discussed. Powered by TCPDF (www.tcpdf.org).

View Full Text

Details

  • File Type
    pdf
  • Upload Time
    -
  • Content Languages
    English
  • Upload User
    Anonymous/Not logged-in
  • File Pages
    1 Page
  • File Size
    -

Download

Channel Download Status
Express Download Enable

Copyright

We respect the copyrights and intellectual property rights of all users. All uploaded documents are either original works of the uploader or authorized works of the rightful owners.

  • Not to be reproduced or distributed without explicit permission.
  • Not used for commercial purposes outside of approved use cases.
  • Not used to infringe on the rights of the original creators.
  • If you believe any content infringes your copyright, please contact us immediately.

Support

For help with questions, suggestions, or problems, please contact us