Geochemical Features of Magmas of the Largest Holocene Eruption of Khangar Volcano (Sredinny Range, Kamchatka): Melt Inclusion Evidence

Abstract

Melt inclusions were investigated in the minerals of dacite tephra of the largest Holocene eruption (7900 years) of Khangar volcano, Sredinny Range of Kamchatka. Melt compositions correspond to rhyolite (SiO2 = 70–77 wt %, Na2O+K2O = 6–7 wt %) with ~5 wt % H2O. The melts show a minor negative Nb anomaly and lesser HREE depletion (La/Yb is ~7.1) compared to those of Ichinsky Volcano, another active volcano of the Sredinny Range of Kamchatka. It was determined that different phenocryst assemblages were formed within temperature ranges of 750–785 and 830–870°C. Evidence for the assimilation of granite-gneiss basement by magmas of Khangar volcano are discussed.