The basin-range system along the south segment of the Karakorum fault zone, Tibet

The Karakorum fault zone (KFZ), one of the most important faults in the western Tibetan Plateau, plays a significant role in accommodating crust rotating around the west syntaxis and lateral mass transfer. Our study on the south segment of the fault shows that both sides of the Aylari Range are controlled by right-lateral strike-slip fault branches of the KFZ with a normal fault component. The offset along the south fault segment of the KFZ is about 100 km. Sedimentary characteristics in the Zhada Basin demonstrate that the sediment source mainly was the Aylari Range; thus the basin is probably a half-graben controlled by the late Cenozoic uplift of the Aylari Range. Furthermore, the limited outcrops in the Namru-Menci Basin, together with the main branch of the KFZ passing through the southwestern side of the basin, show that the Aylari Range is the main source of basin sediment. We conclude the Namru-Menci Basin is another graben controlled by the KFZ. Thus, the Zhada Basin, Aylari Range, and Namru-Menci Basin together form a basin-range system along the southeastern portion of the KFZ. The right-lateral KFZ strike-slip was gradually transferred to the extensional system southeast of Gar, which is the basin-range system composed of the Zhada and Numru-Menci basins and Aylari Range, together with the Gurla Mandhata detachment system. The basin-range system in this study confirms that the KFZ reflects distributed deformation of lateral mass transfer during the Indian-Asian block convergence.