Himalayan tectonics explained by extrusion of a low-viscosity crustal channel coupled to focused surface denudation

Recent interpretations of Himalayan–Tibetan tectonics have proposed that channel flow in the middle to lower crust can explain outward growth of the Tibetan plateau, and that ductile extrusion of high-grade metamorphic rocks between coeval normal- and thrust-sense shear zones can explain exhumation of the Greater Himalayan sequence. Here we use coupled thermal–mechanical numerical models to show that these two processes—channel flow and ductile extrusion—may be dynamically linked through the effects of surface denudation focused at the edge of a plateau that is underlain by low-viscosity material. Our models provide an internally self-consistent explanation for many observed features of the Himalayan–Tibetan system.

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