岡山県久米郡坪井地域の三部変成岩類の残存火成鉱物

The Sangun metamorphic rocks of the Maniwa Group are well developed in the Tsuboi district, Okayama Prefecture. These metamorphic rocks consist mainly of psammitic and pelitic sedimentary rocks and lavas and pyroclastics of basic to acidic compositions that recrystallized during the Sangun low-grade regional metamorphism. The metamorphic rocks in this district underwent to a considerable extent a mineralogical and textural transformation, but still preserve in parts their original, mineralogical and textural features. Unaltered, relict clinopyroxenes and hornblendes are commonly observed in the metamorphic rocks derived from basic lavas and intermediate pyroclastics. Microprobe analyses of these relict minerals suggest that their host rocks were probably derivatives of magma(s) with a non-alkaline affinity.

原著論文 (Original Papers)