Seismic image of the Tarim basin and its collision with Tibet

A broadband seismic deployment in 1998-1999 in southwestern Tarim provided data for imaging the crust and upper mantle across the contact between the Tarim block and the Tibetan Plateau. A profile composed of migrated telesei smic receiver functions clearly shows lateral structural changes. The crust under the Tarim basin is relatively simple, The Moho discontinuity is mapp ed at a depth of 42 km near the northern end of the array and dips gently t oward the south to similar to 50 km under the Kunlun foreland. The Tarim ba sin appears to be rigid, with little shortening. Farther to the south, the imaging reveals a complex of reflectors in the lower crust and the upper ma ntle. There are both north- and south-dipping upper mantle structures under the Kunlun foreland and Kunlun Shan region. We found the observations to b e more consistent with a model of lithospheric collision in which the crust and the upper mantle on both sides interpenetrate and deform.