Structure and Stress Field of the Lithosphere Between Pamir and Tarim
Wasja Bloch, Bernd Schurr, Xiaohui Yuan, Lothar Ratschbacher, Sanaa Reuter, Sofia‐Katerina Kufner, Qiang Xu, Junmeng Zhao
Abstract
Abstract The Pamir plateau protrudes ∼300 km between the Tajik‐ and Tarim‐basin lithosphere of Central Asia. Whether its salient location and shape are caused by forceful indentation of a promontory of Indian mantle lithosphere is debated. We present a new local‐seismicity and focal‐mechanism catalog, and a P‐ wave velocity model of the eastern part of the collision system. The data suggest a south‐dipping Asian slab that overturns in its easternmost segment. The largest principal stress at depth acts normal on the slab and is orientated parallel to the plate convergence direction. In front (south) of the Asian slab, a volume of mantle with elevated velocities and lined by weak seismicity constitutes the postulated Indian mantle indenter. We propose that the indenter delaminates and overturns the Asian slab, underthrusts the Tarim lithosphere along a compressive transform boundary, and controls the location and shape of the Pamir plateau.