Kanasaki
Kanasaki, Minano city, Chichibu county, Saitama pref., Japan
Occurrence
Besshi massive sulfide deposit
Very small scale of Besshi Massive Sulfide Deposit associated with tuff in Sanbagawa Metamorphic Rocks subjected to Greenschist facies metamorphism. The protolith is tuff.
Outcrop of greenschist paralle to its schistosity Sanbagawa Metamorphic Rocks. Rectangular crystals of euhedral yellow pyrites are scattered on the surface of greenschist. Brown dirt around pyrite crystals are limonite formed by weathering of pyrite. Dark green parts around pyrite crystals are fibrous chlorite. This fibrous chlorite shows distribution of pressure shadow around rigid pyrite crystals when it was in high pressure. By studying detailed direction of pressure shadow, high pressure direction during metamorphism is revealed. Very fine white crystals all over the surface of greenschist are albite spots which are good index of higher metamorphic condition.
Reported Minerals
- Pyrite
- Magnetite
- Stilpnomelane
Mineral Assemblages
- Greenschist - Pyrite - Albite
- Greenschist - Magnetite - Albite
- Stilpnomelane schist
Localities
- Hitachi Mine (Cu, EA facies)
- Besshi Mine (Cu, EA facies)
- Iwadono Mine (Pyrite, EA facies)
- Hidaka Mine (Cu, GS facies)
- Shizuka Mine (Ni, GS facies)
- Kanasaki (Pyrite, GS facies)
Related Occurrences
- Greenschist facies
- Blueschist facies
- Epidote-Amphibolite facies
- Amphibolite facies
- Eclogite facies
- Low-P granulite facies
- High-P granulite facies