Yangtze craton modification initiated by tearing of the subducted Indian slab: New image from a short-period dense seismic array in eastern Tibetan Plateau

Most cratons are ancient and stable due to their dry, buoyant and thick lithospheric roots, but some experienced keel deformation and crustal destruction during continental collisions, with the triggers remaining unclear. Here, we construct a fine structure of the crust beneath the Western Yangtze Craton (WYC) underlying a inferred Indian slab tear zone formed since ∼ 50 Ma, by deploying a 400 km long short-period dense seismic array across the eastern Tibetan Plateau. Our receiver function images reveal that the WYC lithosphere underwent severe intra-crustal deformation, including crustal thickening prior to 40 Ma and subsequent fragmentation by collision-induced strike-slip faulting since the Eocene. Combining seismic imaging with geologic records, we demonstrate that the cratonic lower crust above the tear zone suffered partial melting, mantle-melt injection, and vertical rupture during the Cenozoic India-Asia collision. Based on the previously established model of a torn window formed by the vertical tearing of Indian slab subducting beneath the WYC, we propose that the upward and lateral asthenospheric flow through this window induced thermal weakening of the overlying WYC lithosphere, ultimately leading to its rupture and crustal destruction. This process also controls the focused distribution of Eocene magmas along the tear zone and the abrupt change in crustal thickness across the same region. Our study provides a novel insight into the mechanism of cratonic destruction, highlighting the role of slab tearing in driving lithospheric weakening and crustal recycling.