Kami-Nagatoro
Kami-Nagatoro, Nagatoro city, Chichibu county, Saitama pref., Japan
Closed to collecting as it is a natural monument.
Occurrence
Greenschist facies metamorphic rocks
Sanbagawa Metamorphic Rocks subjected to Blueschist facies - Greenschist facies metamorphism. The protolith is volcaniclastic rocks such as tuff.
Outcrop of stilpnomelane schist of Sanbagawa Metamorphic Rocks. Local peoplecalled this outcrop "Tora-iwa" ("Tiger rock" in Japanese) because it looks like the pattern of tiger fur. Dark brown parts are rich in stilpnomelane. The white veins perpendicular to the schistosity are fibrous calcite, and it grows perpendicular to the vein walls. There are tiny octahedral magnetite crystals on the surface of the outcrop.
Reported Minerals
- Stilpnomelane
- Calcite
- Magnetite
- Malachite
- Copper
Mineral Assemblages
- Stilpnomelane - Calcite - Magnetite
- Malachite - Copper
Localities
- Kami-Nagatoro (Stilpnomelane, High-P)
- Banjo (Glaucophane, High-P)
- Yamabuki creek (Hematite, High-P)
- Yoshimi (Zeolite, High-P)
- Kami-Suwa (Chloritoid, Middle-P)
- Takarayama Mine (Quartz, Middle-P)
Related Occurrences
- Albite-Epidote-hornfels facies
- Hornblende-hornfels facies
- Pyroxene-hornfels facies
- Sanidinite-hornfels facies
- Pumpellyite-Actinolite facies
- Blueschist facies
- Epidote-Amphibolite facies
- Eclogite facies
- Ultrahigh-pressure faices