Intra‐Continental Collision of the Tarim Basin and the Northern Tibetan Plateau.

The seismic data recorded at 48 broadband stations on an 1,800‐km‐long linear array have been used to image the deep structure and deformation in the intra‐continental collision between the Tarim Basin and the Northern Tibetan Plateau (NTP). Common Conversion Point (CCP) stacking imaging along the linear array and joint inversion of receiver function and surface wave dispersion defined the crustal and upper mantle structure, indicating that the Tarim block underthrusts the Altyn Tagh Range–Qaidam Basin. Whereas Moho is flattened, the lithospheric mantle beneath the Qaidam Basin has unusually low velocity, which is thought to be the consequence of the delamination in the lower crust and mantle lithosphere. Strong positive phase occurring at depths of 150–200 km on the CCP stacking imaging is likely to be associated to the remnant subducted oceanic lithospheric slab or the underthrusting Tianshan lithospheric slab beneath the collision zone. The removal of the Altyn Tagh Range–Qaidam Basin orogenic root may be due to convection‐driven delamination underneath it and subsequent underthrusting of the Tarim block. The spatial variation of the SKS splitting is manifested as the large‐scale pattern of lithospheric deformation and local abrupt changes, transitioning from pure shear on the NTP to simple shear in the Altyn Tagh Range. A comprehensive analysis of SKS splitting and GPS data reveals a simple shear pattern of vertical coherent deformation in the Altyn Tagh Range and its adjacent areas, which is evidence of the lithospheric shear zones. Plain Language Summary: The seismic wave data received by 48 broadband stations on the newly 1,800 km long linear array were used to determine the deep structure and deformation of the crust and upper mantle caused by the intra‐continental collision between the Tarim block and the Northern Tibetan Plateau by the joint inversion of the receiver function and the surface wave dispersion method. The results of this study reveal that the Tarim block underthrusts the Altyn Tagh Range–Qaidam Basin, and the Moho discontinuity below it appears nearly flat, indicating that the underlying orogenic roots have been removed. The mantle lithosphere below the Qaidam Basin is a low‐velocity anomaly zone which is thought to be evidence of the delamination of the lower crust and upper mantle. Convection‐driven delamination underneath the Qaidam Basin and subsequent underthrusting of the Tarim block resulted in the removal of the orogenic roots below the Altyn Tagh Range–Qaidam Basin. The delamination and uplift resulted in the shortening and thickening of the Altyn Tagh Range–Qaidam Basin. A comprehensive analysis of SKS splitting and GPS data reveals the vertical coherent deformation of the Altyn Tagh Range. The consistency between the coherent SKS fast direction and the strike of the crustal faults is considered evidence of simple shear of the Altyn Tagh Range. Key Points: Flat Moho and anomalous low‐velocity lithospheric mantle beneath the Qaidam Basin are thought to be the consequence of delaminationStrong positive phases of receiver function at depth of 150–200 km may be related to the remnant subducted Tarim oceanic lithospheric slabSimple shear pattern of vertical coherent deformation resulting from SKS splitting suggests that the Altyn Tagh Range is a lithospheric shear zone [ABSTRACT FROM AUTHOR]