Northward thinning of Tibetan crust revealed by virtual seismic profiles

Abstract

A new approach of constructing deep‐penetrating seismic profiles reveals significant, regional variations in crustal thickness under near‐constant elevation of Tibet. Over distances of hundreds of kilometers, the crust is as thick as 75 km in southern Tibet but shoals to just over 60 km under the Qiangtang terrane in central Tibet where the deviation from Airy isostasy is equivalent to a thickness of over 10 km in missing crust. Northward thinning of crust occurs gradually over a distance of about 200 km where mechanical deformation, instead of pervasive magmatism, also seems to have disrupted the crust‐mantle interface.