Mantle sources of Permian-Triassic Siberian traps (West Siberian Plate and Siberian craton)
V.N. Sharapov a , Yu.V. Perepechko a , L.N. Perepechko b , I.F. Rakhmenkulova c
a Institute of Geology and Mineralogy, Siberian Branch of the RAS, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
b Institute of Thermal Physics, Siberian Branch of the RAS, 1 prosp. Akad. Lavrentieva, Novosibirsk, 630090, Russia
c Novosibirsk State University, 2 ul. Pirogova, Novosibirsk, 630090, Russia
Keywords: Mantle-crust magmatic systems; melting; mathematical modeling
Pages: 492-502
Abstract
We investigate the dynamics of multilevel subcontinental melting beneath a lithosphere of variable thickness as a model simulating generation of melts that produced flood basalt in the Siberian Trap province. The inferred sequence of volcanic events correlates with upper mantle decompression melting above hotspots and related conductive melting of metasomatized depleted lithosphere. Numerical experiments show that complex mafic magmatic systems of this kind are at least two-stage with a zone of decompression melting in upwelling mantle flow and a sub-Moho lithospheric melting region; the shallower lithospheric melting region can be disconnected from the mantle zone of decompression melting along the edges of the magmatic system; the lithospheric melting region has a particular layered structure with its top at a depth of 60-70 km and a maximum size exceeding the length of the erupted lava field; mafic melts produced at different levels of the system have different compositions.
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