EPMA study on Sr content of plagioclase in the Hakusan volcanic rocks

Abstract

Strontium content of plagioclase in volcanic rocks from Hakusan were determined using EPMA techniques. Interiors of dusty zone of phenocrysts are constantly poor in Sr (<0.20 wt. % SrO), while the Sr content outside the zone is rather high (up to 0.40 wt. %). Results of calculation using partition coefficients of Sr suggests that the interiors coexisted with felsic melts with <400 ppm Sr, while the exteriors crystallized from mafic melts varyingly rich in Sr up to 1200 ppm.