Daioin
Daioin, Miyata village, Hitachi city, Ibaraki pref., Japan
Occurrence
Limestone of the Cambrian (500 Ma) Daioin Formation subjected to Greenschist facies metamorphism in the Late Cretaceous (100 Ma) medium-P Abukuma metamorphic belt. Age of limestone was determined by coral fossil, and metamorphic age by K-Ar radiometric dating of muscovite.
The white bed under the coin is crystalline limestone of theDaioin Formation. Both sides of the limestone bed is greenschist with clear schistosity. Pelitic schist is also distrubuted near this outcrop.
Reported Minerals
- Calcite
- Fuchsite?
- Cordierite
Mineral Assemblages
- Calcite - Fuchsite?
- Pelitic schist(Host) - Cordierite - Muscovite - Quartz
Localities
- Shiroishi (Sanbagawa belt, High-P)
- Daioin (Hitachi-Takanuki belt, Medium-P)
- Hanazono Cave (Hitachi-Takanuki belt, Medium-P)