EGU21-9901, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-9901
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Large recent counterclockwise rotations in the Tajik Basin and implications on the Pamir salient formation

Lin Li1,2, Guillaume Dupont-Nivet1,3, Pierrick Roperch1, Yani Najman4, Mustafa Kaya3, Niels Meijer3, and Jovid Aminov5
Lin Li et al.
  • 1University of Rennes 1, CNRS, Géosciences Rennes-UMR 6118, Rennes, France (li.lin8611@gmail.com)
  • 2Department of Environmental Sciences, Rochester Institute of Technology, Rochester, NY, USA
  • 3Institute of Geosciences, Potsdam University, Potsdam, Germany
  • 4Lancaster Environment Centre, Lancaster University, Lancaster, UK
  • 5Institute of geology, earthquake engineering and seismology, Academy of Sciences, Dushanbe, Republic of Tajikistan

Contrasting models have been proposed to explain the formation of the Pamir salient: either largely inherited from a Mesozoic arcuate structure or recently formed by Indian northward indentation and possibly related to syn-orogenic lateral extrusion. The vertical-axis counterclockwise rotations observed in the Tajik Basin are key constraints on testing these models, but the timing of these rotations remains hindered by poor age control on the basin sediments. We report a combined analysis of vertical-axis rotation and magnetostratigraphic dating of a long sedimentary section in the eastern Tajik Basin, which yields strong counterclockwise rotations (~56°) in early Late Cretaceous to late Miocene strata. This result suggests that rotation in the Tajik Basin occurred after ~8 Ma, much later than previously suggested. Combining with a regional compilation of previous paleomagnetic studies as well as structural and GPS constraints including Pamir and Tarim, we explore potential implications on models of the Pamir salient. We infer that after 8 Ma (probably even later), the Pamir (North, Central, and South) began to overthrust west- and northwest-ward, causing counterclockwise rotations in the Tajik Basin. This reconstruction allows for ~150 km of post-8 Ma northwestward indentation into the Tajik Basin, in agreement with coeval underthrusting of the Indian mantle lithosphere into Asia.

How to cite: Li, L., Dupont-Nivet, G., Roperch, P., Najman, Y., Kaya, M., Meijer, N., and Aminov, J.: Large recent counterclockwise rotations in the Tajik Basin and implications on the Pamir salient formation, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9901, https://doi.org/10.5194/egusphere-egu21-9901, 2021.

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