Parental Melts of the Last Volcanic Pulse in the Sedanka Field, Sredinny Range, Kamchatka

摘要

Compositions of melts for the youngest and located hypsometrically below others eruption centers of Sedankinskiy field of areal volcanics were studied by the olivine-hosted melt inclusions method. The trace-element content in the melts is reported for the first time. It is argued that the previously described low-potas-sium melt group is a melting product of heterogeneous inclusions. The melts of these eruptions differ from those of the Kekunai field of areal volcanic rocks in trace element content within the measurement uncertainty. Having similar geochemical characteristics, they are in equilibrium with more magnesian olivine and, therefore, are the most primitive for the Holocene volcanic rocks of the Sredinny Range.The melts of the studied eruptions, which are in equilibrium with the most magnesian olivine, fall in the field of pyroxenite melting under hydrous conditions in the CMAS diagram and may be the result of nearly pure pyroxenite melting.