Teleseismic imaging of subducting lithosphere and Moho offsets beneath western Tibet

Teleseismic images suggest that the Tarim plate plunges ∼45°S, down to ∼300 km depth, beneath NW Tibet. The 410 km discontinuity shallows by ∼10 km under the plateau, implying ∼100°C cooler upper mantle. The deepest Moho on record (∼90 km) lies under W Qiangtang. It rises abruptly by ∼20 and ∼10 km beneath the Altyn Tagh Fault and Bangong Suture, respectively. Vp/Vs ratios are normal, except in the Yecheng flexural basin and deep under the south Karakax volcanics (∼1.92). W Kunlun’s Neogene tectonics are simply accounted for by oblique subduction of lithospheric mantle beneath an upward-extruding thrust wedge of the Tarim crust.