Crustal channel flows: 2. Numerical models with implications for metamorphism in the Himalayan-Tibetan orogen

摘要: [1] Results from a thermal-mechanical model (HT1) that includes midcrustal channel flow are compatible with many features of the Himalayan-Tibetan system. Radioactive self-heating and rheological weakening thickened orogenic crust lead to formation hot, low-viscosity broad plateau. Channel material, corresponding Greater Himalayan Sequence (GHS), flows outward beneath plateau in response topographically induced differential pressure. At flank it is exhumed by focused surface denudation juxtaposed cooler, newly accreted material Lesser (LHS). The bounded coeval thrust normal sense ductile shear zones, interpreted represent Main Central Thrust (MCT) zone South Tibetan Detachment system, respectively. Inverted metamorphism associated MCT results distributed along extrusion hot channel. A variety P-T-t path styles, resembling those observed GHS LHS, produced for points traveling through contrasting tectonic regimes coexist different parts model. Predicted times peak metamorphism, cooling, erosion metamorphic facies generally observations, although cooling ages too young. M1 M2 “events” correspond maximum burial heating, highlight need integrate tectonics continental collision models demonstrate importance lateral transport both heat large orogens.