The wedging of the Namjagbarwa syntaxis in southeastern Xizang and its geological effects

The Namjagbarwa syntaxis consists of three tectonic units: the central Himalayan tectonic unit, and marginal Gangdise and Yarlung Zangbo tectonic units. The Namjagbarwa wedge structures are represented by the Himalayan tectonic unit as a structural wedge, and its surrounding right- and left-dextral strike-slip faults systems. The wedging of the Namjagbarwa syntaxis, in turn, has permitted the transcurrent dislocation of the Yarlung Zangbo suture zone and the formation of the Yunnan-Xizang whirl structures, from which the Yarlung Zangbo Grand Canyon resulted as the most magnificent canyon in the world. The genesis of the Namjagbarwa wedge structures is interpreted to be related to the continuous northward compression and counterclockwise rotation generated during the northward shift of the Indian plate. The wedging processes include three stages of point collision (>45 Ma), collisional wedging (45-7 Ma) and rotational uplift (<7 Ma).