T027-0013
Seismic reflection imaging of crustal deformation within the easternYarlung-Zangbo suture zone

Thursday, 10 December 2020
Poster
Xinyu Dong, Sun Yat-Sen University, School of Earth Sciences and Engineering, Guangzhou, China, Wenhui Li, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, China, Zhanwu Lu, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China, Xingfu Huang, School of Earth Sciences and Engineering, Sun Yat-Sen University, Guangzhou, China and Rui Gao, Sun Yat-Sen University, Guangzhou, China
Abstract:
Various models have been proposed to explain formational mechanisms for the Himalayan orogeny but un-
certainties remain concerning uplift processes and deeper crustal structure of the orogen. Imaging of the orogen's
deep structure can help resolve these uncertainties. This paper describes one migrated deep seismic reflection
profile across the eastern Yarlung-zangbo suture (YZS) at 92° E, which provides a high resolution image of
crustal structure that reveals (1) Yarlhashampo dome is divided into upper, middle and lower tectonic units by
two detachments from rim, mantle to the core of dome, (2) one blind north-dipping reverse fault that offsets the
South Tibet detachment (STD) developed along the northern flank of the Yarlhashampo dome, (3) a shift of the
Main Himalayan thrust (MHT) dip angle from 18° into relatively gentle dips (6°) in the central part of the profile
(18–20 s, t.w.t). Meantime, further inferring that (4) North-south compression event happened after ca.10 Ma in
North Himalayas, (5) multi-stage duplexing as the primary mechanism for crustal thickening in the eastern YZS
based on interpreted structures.
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