三郡変成帯大佐山地域産ひすい輝石物の共生関係と化学組成

Jadeitites (OsaJd and OsaJd2) from the serpentinites of the Osayama ultramafic body in the Sangun metamorphic belt (Suo belt) are petrographically described. Wollastonite and albite are newly found in the jadeitite of OsaJd associated with jadeite, pectolite, grossular and analcite. Magnesiokatophorite has been found from the jadeitite of OsaJd2, and it is associated with jadeite, omphacite, diopside, phlogopite, rutile and titanite. The clinopyroxenes from the jadeitite (OsaJd2) are classified into jadeite, omphacite and diopside. The compositional gaps between jadeite and omphacite and omphacite and diopside have been revealed. Based on the textural relationship a successive formation of clinopyroxenes from jadeite through omphacite and up to diopside is recognized.
Ca-rich minerals such as diopside, wollastonite, pectolite and grossular occur along the cracks within the matrix of jadeites, suggesting later stage Ca-rich fluid infiltration and subsequent participation of such Ca-rich minerals.