Seismic reflection imaging of crustal deformation within the eastern Yarlung-Zangbo suture zone

Various models have been proposed to explain formational mechanisms for the Himalayan orogeny but uncertainties 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 degrees 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 degrees into relatively gentle dips (6 degrees) 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.