- 著者
- Mutsuko INUI Shuto KOJIMA Yoshiya NAGATSUMA
- 出版者
- Japan Association of Mineralogical Sciences
- 雑誌
- Journal of Mineralogical and Petrological Sciences (ISSN:13456296)
- 巻号頁・発行日
- pp.221219c, (Released:2023-10-04)
Albite porphyroblasts occur in schists in higher-grade zones of the Sanbagawa metamorphic belt, Japan. In this study of pelitic schists from the Nagatoro area of the belt, various microstructures in albite porphyroblasts were identified and indicate that grain size reduction of the albite porphyroblasts occurred after their formation. Schists with recognizable porphyroblasts contain fine grains of albite aligned in the matrix. In comparison, schists without recognizable albite porphyroblasts contain lenticular aggregations of albite grains in quartz-rich layers that suggest grain size reduction of the original porphyroblasts. These observations suggest that the absence of albite porphyroblasts does not necessarily indicate different pressure, temperature, or chemical conditions but can instead be explained by grain size reduction of albite porphyroblasts during deformation.