A thermotectonic numerical model of collisional metamorphism in the Mongolian Altai

A mathematical model based on thermomechanical equations of mechanics of deformable solids was suggested to study the mechanism of collision and metamorphism in rocks of the Mongolian Altai orogen. The problem of crust deformation and distribution of the P–T parameters of metamorphism in the Tsogt block in the course of convergence of the Edren island-arc terrane and the Gobi–Altai back-arc terrane was considered. The results of mathematical modeling explain the 1.5-fold thickening of the crust (rock subsidence by 15–18 km), which is consistent with pressure estimates of metamorphism obtained from the data of geothermobarometry. Modeling provides estimates of the plate convergence rate by comparison of the calculated temperatures with the data of thermobarometry for rocks of the Tsogt metamorphic complex within the Tseel terrane.