Bangong suture

The geology of the suture includes Jurassic marine shale and conglomeratic strata, melange and ophiolites and volcanic rocks from multiple pulses of magmatism.

[6] Each of these lithologies can be tied to specific terranes, either island arcs[7] or microcontinents, that were gathered in front of the Indian subcontinent as it drifted northward during the Mesozoic.

During the Jurassic-Cretaceous collision[8] of the Lhasa and Qiangtang terranes, the ancient Tethys ocean closed,[1][8] creating the Bangong suture zone.

[8] Suturing of microcontinents was followed by the continued northward drift of the Indian subcontinent, colliding with Eurasia during the Cenozoic, about 45-55 million years ago.

[9] The closure of the Neo-Tethys Ocean occurred at this time,[1] as the southern edge of Eurasia (marked by the Lhasa terrane), collided with India.

The "soft Tibet" model suggests that a series of small multiple faults along the suture zone would occur, due to the ductile nature of the lithosphere.

General map of central and southern Tibet depicting the Bangong suture (located between the BSZ and Qiangtang terrane) and Bangong suture zone (BSZ) and surrounding terranes . Map is modified from Guynn et al., 2011. [ 1 ]
Cross section depicting the tectonic evolution of the Bangong suture zone. 1. An oceanic backarc basin forms separating the Amdo basement from the Qiangtang terrane. Slab rollback is a possible explanation for this extension. 2. Continued subduction of oceanic crust in the early-middle Jurassic. Closure of the oceanic back arc basin causes ophiolite obduction and a period of metamorphism in the Amdo basement. 3. In the early Cretaceous, the Lhasa and Qiangtang terranes collide creating the Bangong suture. A foreland basin also forms at this time. Cross section is modified from Guynn et al., 2006. [ 8 ]