ESTIMATION OF THERMODYNAMIC PARAMETERS OF THE MOHO DISCONTINUITY BENEATH THE AREA OF TRAP DEVELOPMENT ON THE SIBERIAN PLATFORM AND WEST SIBERIAN PLATE
V.N. Sharapov and O.V. Kudryavtseva*
Institute of Geology, Siberian Branch of the RAS, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
* Novosibisrk State University, 2 ul. Pirogova, Novosibirsk, 630090, Russia
Keywords: Eclogites, fluid, thermodynamic facies, zoning
Pages: 954-967
Abstract
Numerical modeling based on the Selektor-C software was used to analyze the thermodynamic conditions of eclogitization of basic rocks in the Earth's crust section of the Siberian Platform, which is associated with the coronite formation in differentiated basic rocks of the Yenisei Range. Schematic facies of development of equilibrium associations of metamorphic minerals have been constructed for initial compositions of layered basic rocks in the presence of a fluid of varying composition, and the behavior of the density of apobasitic rocks has been shown as a function of T and P. It is found that local variations of coronite composition are controlled first of all by the amount and composition of the fluid. An assemblage of ilmenite, K-feldspar, and biotite in coronas unambiguously indicate the presence of a water-bearing fluid at pressures of less than 9 kbar and temperatures of more than 750
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