Fragmentation of continental subduction is ending the Himalayan orogeny

Xiaofeng Liang; Yang Chu; Bo Wan; Ling Chen; Lin Chen; Eric Sandvol; Stephen P Grand; Yibing Li; Minling Wang; Xiaobo Tian; Yun Chen; Tao Xu; Yang Li; Wei-Qiang Ji

doi:10.1016/j.scib.2023.10.017

Fragmentation of continental subduction is ending the Himalayan orogeny

Sci Bull (Beijing). 2023 Dec 15;68(23):3048-3054. doi: 10.1016/j.scib.2023.10.017. Epub 2023 Oct 27.

Authors

Xiaofeng Liang¹, Yang Chu², Bo Wan², Ling Chen³, Lin Chen², Eric Sandvol⁴, Stephen P Grand⁵, Yibing Li², Minling Wang⁶, Xiaobo Tian², Yun Chen³, Tao Xu², Yang Li², Wei-Qiang Ji²

Affiliations

¹ State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences (CAS), Beijing 100029, China. Electronic address: liangxf@mail.iggcas.ac.cn.
² State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences (CAS), Beijing 100029, China.
³ State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences (CAS), Beijing 100029, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China.
⁴ Department of Geological Sciences, University of Missouri, Columbia MO 65211, USA.
⁵ Department of Geological Sciences, University of Texas at Austin, Austin TX 78712, USA.
⁶ College of Earth Sciences, Guilin University of Technology, Guilin 541004, China.

PMID: 37919155
DOI: 10.1016/j.scib.2023.10.017

Abstract

After two continents collide, plate convergence and orogenesis are sustained because subducted continental lithosphere continues pulling the surface plate. It remains controversial how, why, and when continental plate convergence and collision slow down and eventually cease. We use an unprecedented data coverage and present a regional-scale seismic tomographic image of the mantle structure beneath the Tibetan Plateau. In the mantle transition zone, we identify multiple high-velocity anomalies and interpret them as detached pieces of the Indian continental slab. Facilitated by internal heterogeneity of the continental lithosphere, piecewise slab detachments could reduce the slab pull force, resulting in the Miocene slowdown of the India-Eurasia convergence and coeval diachronous potassic volcanism in southern Tibet. We propose that slab detachment is a mechanism that eventually will lead to the end of the Indo-Eurasian continental collision and the Himalayan orogeny.

Keywords: Continental collision; Seismic tomography; Slab fragmentation; Slab pull; Tibetan Plateau.