HETEROGENEITY OF MANTLE SOURCE OF LATER PLEISTOCENE-HOLOCENE MONOGENETIC VOLCANISM IN SREDINNY RIDGE OF KAMCHATKA

Petrography, petrochemistry and geochemistry of rocks, as well as major, trace and volatile (F, Cl) elements content in melt and solid phase inclusions in olivines of monogenetic basalts of South Cherpouk and Mt. Skalistaya have been studied, which are situated in Sredinny Ridge of Kamchatka, south-westward of Ichinsky volcano, more then in 200 km from volcanic front. Although the studied objects are very remote from present sudbuction zone, monogenetic field of Mt. Skalistaya is Later Pleistocene, and South Cherpouk’s eruptions took place only 6500 14С years BP [4]. Brief conclusions of the investigation: 1) All studied rocks of monogenetic lava fields of Ichinkaya zone of Sredinny Ridge are substantially enriched by all incompatible elements. Data on major and trace elements of melt inclusions and compositions of solid phase inclusions in olivines indicate the presence of enriched OIB-like source in this region. Presence of «sudbuction » signatures in all rocks indicates that melting took place most likely in the mantle wedge. 2) Melt compositions demonstrate that all chemically different rocks of South Cherpouk can be described by fractional crystallization processes and can be genetically related. On th