Sillimanite-cordierite bearing pelitic gneiss from the Mt. Sangun area, North Kyushu

Abstract

The Sangun-Renge belt (Sangun belt) is well known as the high-pressure type metamorphic belt. Here we report pelitic gneisses from both areas and discuss the implications for the pelitic gneisses from the Sasaguri and Iiduka areas, the Sangun belt. In the Sasaguri area the pelitic gneisses are composed mainly of quartz, plagioclace, muscovite and biotite with a minor amount of garnet. The pelitic gneisses from the Iiduka area comprise quartz, plagioclace, biotite with locally including andalusite, silimanite (fibrolite) and cordierite. Fibrolites and cordierites surround the corroded andalusite and form foliations together with biotites. Judging from mineral textures, the pelitic gneiss from the Iiduka area would, therefore, be suffered by regional metamorphism with low-P/high-T type.