Earth Science Frontiers ›› 2023, Vol. 30 ›› Issue (2): 57-67.DOI: 10.13745/j.esf.sf.2022.8.56

• Special Section on The India-Eurasia Collision and Its Long-Range Effect (Part 6) • Previous Articles     Next Articles

Moho geometry in the eastern North Himalayan tectonic belt: An example of the receiver function 3DCCP method

LI Chunsen1,2(), XU Xiao1,2,*(), XIANG Bo1,2,*(), GUO Xiaoyu1,2, WU You1,2, WU Jiajie1,2, LUO Xucong1,2, YU Jiahao1,2, TONG Xiaofei1,2, YUAN Zizhao1,2, LIN Yanqi1,2   

  1. 1. School of Earth Sciences and Engineering, Sun Yat-sen University, Zhuhai 519082, China
    2. Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China
  • Received:2022-05-21 Revised:2022-08-25 Online:2023-03-25 Published:2023-01-05
  • Contact: XU Xiao,XIANG Bo

Abstract:

The India-Eurasia collision zone remains uncertain with respect to deep geological contacts beneath the eastern North Himalayan tectonic belt. In order to confirm the specific Moho interface beneath the dominant collision zone, we obtained high-resolution 3D Moho geometry in the region based on data generated by the deployed short-period dense array and previously published broadband station, by tele-seismic P-wave 3DCCP stack method using the improved Moho picking algorithm. Together with previous 2DCCP profiles, tomography and magnetotelluric profiles, we obtain the following results: (1) the Moho depth increases from ~60 km beneath the Great Himalayas to ~70-75 km beneath the dominant collision zone (YZSZ, the Yarlung-Zangbo suture zone). (2) An 120 km-long east-west-oriented depth gradient of the Moho interface exists at about 28.9°N to the south of YZSZ, where appears opposite Moho dip direction constituting the depth gradient. (3) The Moho interface dipping to the north represents the subducting Indian crust and indicates no further extension of the Indian crust beyond YZSZ to the north. In a broader context, this Moho depth gradient to the south of YZSZ in the eastern North Himalayas is resulted from subduction resistance by the juvenile southern Lhasa terrane and the contemporaneous clockwise rotation of the Indian continent that is pulled by the ongoing subduction of the Indian oceanic crust to the east of the Eastern Himalayan Syntax.

Key words: northern Himalayan tectonic belt, receiver function, 3DCCP stack, 3D Moho structure

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