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Crustal resistivity structure of the Lunpola basin in central Tibet and its tectonic implications
  • Shuai Xue,
  • Zhanwu Lu
Shuai Xue
Institute of Geology, Chinese Academy of Geological Sciences
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Zhanwu Lu
Institute of Geology, Chinese Academy of Geological Sciences

Corresponding Author:[email protected]

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Abstract

In the central Tibetan Plateau, an east-west trending band of basins is developed. How such topography formed and the underlying geodynamic processes are still in debate. Magnetotelluric data were collected across the Lunpola basin to study the crustal structure beneath central Tibet. Phase tensors and 3-D inversion are employed to obtain the electrical resistivity model. Our model clearly portrays conductive sedimentary layers beneath the basins with average resistivity of 2.0 Ω·m. The low-resistivity mid-to-lower crust is revealed beneath the Lunpola basin with bulk resistivity of 20 Ω·m and fluid fraction of 1.3-3.0%, which would be attributed to partial melting. Compared to the significant conductive crust in southern Tibet, the crustal rheology is less well developed beneath central Tibet. We propose that the asthenospheric flow beneath central Tibet is responsible for the crustal partial melting and drives the eastward escape of the continental lithosphere in a rigid block fashion.
20 Sep 2023Submitted to ESS Open Archive
30 Sep 2023Published in ESS Open Archive