Cenozoic eastward growth of the Tibetan Plateau controlled by tearing of the Indian slab

Formation of the Tibetan Plateau is generally ascribed to the Cenozoic India–Asia collision. However, the origin of along-strike deformation of the Indian mantle lithosphere, especially beneath the eastern Tibetan Plateau region, and its effect on the plateau’s eastward growth remain unclear. Here, we conduct multiscale seismic tomography to provide a revised structure of the Indian mantle lithosphere beneath the eastern Tibetan Plateau region. Our results demonstrate that the Indian mantle lithosphere is currently torn vertically along ~26° N, with its northern portion shallowly subducting northeastwards and the southern portion steeply subducting eastwards into the mantle transition zone. Analysis of tectonic and magmatic records is consistent with advancing and retreating migration of the slab tear after about 50 Myr ago. We suggest that the rigid Yangtze cratonic lithosphere tore the intruding cratonic Indian mantle lithosphere approximately 35 Myr ago, resulting in diverging shallow subduction. The subsequent Miocene rollback of the southeastern Indian mantle lithosphere is proposed to induce a giant turbo-engine-like flow that caused clockwise rotation of the plateau crust and underlying mantle around the eastern syntaxis, leading to differential eastward growth of the Tibetan Plateau.