Iri-Karuizawa
Iri-Karuisawa, Soehi, Sanada village, Ueda city, Nagano pref., Japan
Occurrence
Neutral metasomatic rocks of Illite-Chlorite zone
Epidote Group minerals formed by hydrothermal alteration of dacitic-rhyolitic tuff, dacite, and rhyolite of Taroyama Formation by late Miocene (9 Ma) Sugadaira Quartz Diorite. Sugadaira Quartz Diorite is I-type (Magnetite-series). Approximately 5 km apart from the Sugadaira Quartz Diorite, the heat source. Ages of sedimentary rocks were determined by microfossils, quartz diorite by K-Ar radiometric dating of whole rock.
Reported Minerals
- Thulite
- Epidote
- Quartz
- Beta quartz
Mineral Assemblages
- Thulite
- Epidote - Quartz
- Rhyolite(Host) - Beta quartz
Details of the mine
Production of thulite has been known since 1900's.
Localities
- Awashiro Mine (Sericitization)
- Harimichi Pass (Sericitization)
- Iri-Kruizawa (Thulite)
- Kami-Takeshi (Epidote, Nodule)
Related Occurrences
- Halloysite zone (Alunite zone, Argillized zone)
- Kaolinite zone (Alunite zone, Argillized zone)
- Minamiite-Alunite zone (Alunite zone)
- Pyrophyllite zone
- Smectite zone (Argillized zone)
- Interstratified mineral zone (Argillized zone)
- Illite-Chlorite zone (Propylite zone)
- Epidote-Actinolite zone
- Stilbite-Mordenite zone (Zeolite zone)
- Heulandite-Analcime zone (Zeolite zone)
- Laumontite-Albite zone (Zeolite z., Propylite z.)
- Wairakite-Albite zone (Zeolite zone)