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Information × Registration Number 0206U004195, 0101U000449 , R & D reports Title Sources of magmatism and mechanisms of magma transport in the upper mantie and the Earts's crust popup.stage_title Head Khazan Y., Registration Date 14-02-2006 Organization S.I.Subbotin Institute of geophysics HASU. popup.description2 The project goal: study of physical mechanisms and implications of generation and migration of melts in the Earth's upper mantle and crust.Investigation methods: mathematical and numerical modeling.The conditions are studied under which the propagation of a fluid driven crack can result in formation of a shear fracture at its edge. The pressure dependence of the structure of the process zone, which most probably is the source of xenoliths entrained by magmatic dikes, is investigated. It is shown that propagation of fluid driven cracks can result in formation of a shear fracture at their edge implying the roof break and a seismic event. It is shown that such a scenario is possible in a case of an internal pressure fluctuation large enough for the both shear and tensile yield thresholds were overcome. It is demonstrated that in the lower crust and upper mantle the process zone at the edge of a magmatic dike is elongated in the direction perpendicular to the crack plane. Most probably this zone is the source of the xenoliths entrained by the magmatic dikes including kimberlites.It is shown that while a melt percolates through a solid matrix a trace element pattern develops that in the limit of the full saturation turns out to be independent neither of melt fraction nor of the source rock modal composition. Most probably this independence is the main reason of the similarity of trace element patterns observed in the world provinces.The evolution of friction in a seismic fault after a frictional melting have occurred is considered. A numerical model is developed that accounts for heat generation due to dry friction prior to melting, viscous dissipation in the melt, selective melting of a polimineral rock, consumption and release of latent heat, temperature dependence of viscosity and heat conductivity and the viscosity dependence on a melting degree. The model is tested against the high velocity laboratory experiments and used to treat the pseudotachilite observations. Product Description popup.authors popup.nrat_date 2020-04-02 Close