Permian magmatism and lithospheric deformation in the Altai caused by crustal and mantle thermal processes
A.G. Vladimirov a , N.N. Kruk a , S.V. Khromykh a , O.P. Polyansky a , V.V. Chervov b , V.G. Vladimirov a , A.V. Travin a , G.A. Babin a , M.L. Kuibida a , V.D. Khomyakov a
a Institute of Geology and Mineralogy, Siberian Branch of the RAS, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
b Institute of Petroleum Geology and Geophysics, Siberian Branch of the RAS, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
Keywords: Geodynamics; plate tectonics; plume tectonics; mathematical modeling; lithospheric deformation; heat and mass transfer; petrological markers of plume activity; Altai collisional shear zone
Pages: 468-479
Abstract
New structural and petrological data have been obtained for the zone of Siberia-Kazakhstan oblique collision for Permian time. In terms of classical tectonics, the area coincides with the Zaisan folded area produced by closure of the Char paleo-ocean in the Late Carboniferous. However, the extent, structure, and composition of magmatism at the Carboniferous-Permian (280 ± 10 Ma) and Permian-Triassic (250 ± 5 Ma) boundaries require an active control from Morgan-type lower mantle plumes (Tarim and Siberian plumes). Structure formation in the lithosphere and heat sources of magmatism have been simulated in a 3D model including lithospheric strain rates (with regard to viscosity layering) and subcontinental upper mantle convection. According to our model, heat supply from slab break-off and/or delamination of lithosphere is insufficient to maintain large-scale mantle-crustal magmatism in the case of oblique collision between 80-100 km thick plates (
|
