Continental Extrusion and Laterally Heterogeneous Deformation Characteristics Within Southeast Tibet

Abstract

Southeast Tibet provides a weak window for continental extrusion and plateau expansion, yet there is still limited understanding regarding specific deformation patterns in this region. Here, we construct a 3‐D crustal anisotropic S‐wave velocity model for the SE Tibetan Plateau. Our new observation retrieved from ambient noise interferometry sheds light on the belt of high‐velocity in the Emeishan Large Igneous Province. This belt is strengthened by the potential trajectory of the mantle plume and serves as a relatively rigid block, which obstructs the possible weak crustal materials from the northwest and transmits compressive stress onto the Xiaojiang fault system. With lower strength, the Xiaojiang fault region accommodates continental extrusion by preferentially deforming, while partial melting of the felsic mid‐lower crust shapes extensive low‐velocity anomalies. Within the context of the continental extrusion, lateral heterogeneity in lithospheric rigidity dominates the non‐uniform deformation of SE Tibet.