THE MAGMATIC EVOLUTION OF THE PLOSKIE SOPKI VOLCANO, KAMCHATKA (ANALYSIS OF THE SR ISOTOPE GEOCHEMISTRY)

First results concerning the study of both geochemistry and Sr isotope systematics in the volcanic series from Ploskie Sopki volcano are presented. Sr isotope data differ significantly for basalts from the shield volcano (0.70342 +/- 2), andesitic basalts of the strata volcano (0.70357 +/- 2), andesites of caldera (0.70370 +/- 5), thes testifying to the existence of both deep (initial)-and subsurface (secondary) magmatic chambers. Fractional crystallization is considered as the main process responsible for diversity of rocks derived from the certain unit of magma generation. Assimilation of crust metamorphic rocks by primitive basaltic melt corresponds to the change between the deep source of magma generation and the within-crust magmatic chamber, where the mixing between 87 wt.% of basaltic magma and 13 wt.% of minimum-temperature granitic crust-derived melt occurs in the presence of water fluid.