Okura Mine
Minamikawa, Hanno city, Saitama pref., Japan
Occurrence
Prehnite-Pumpellyite facies bedded manganese deposit
Chert-hosted bedded manganese deposit in a chert block of Sumaizuku unit, a member of accretionary complexes of Northern Chichibu Belt.
Mine adits of Okura mine. Various colored chert of Sumaizuku unit is observed in the dump. Red chert contains hematite, and black chert contains magnetite and carbonecious materials.
Reported Minerals
- Pyrite
- Hausmannite
- Jacobsite
- Manganosite
- Hematite
- Rhodochrosite
- Baryte
- Caryopilite
- Greenalite
- Rhodonite
- Sepiolite
- Gageite
Mineral Assemblages
- Hausmannite - Jacobsite - Manganosite - Rhodochrosite
- Rhodonite - Quartz - Rhodochrosite
- Caryopilite - Quartz - Baryte
- Hematite - Quartz - Calcite - Sepiolite
Details of the mine
This deposit was mined from 1939 to 1943.
Localities
- Okura Mine (Chichibu belt, Jurassic)
- Agano Mine (Chichibu belt, Jurassic)
- Kamado Mine (Chichibu belt, Jurassic)
- Naguri Mine (Chichibu belt, Jurassic)
- Yamanaka Mine (Chichibu belt, Jurassic)
- Masutomi Mine (Koma Group, Miocene)
- Ochiai Mine (Koma Group, Miocene)
- Tomisato Mine (Koma Group, Miocene)
- Inago Mine (Tanzawa Group, Miocene)
- Takamatsu Mine (Tanzawa Group, Miocene)
- Dainichi Mine (Tanzawa Group, Miocene)
Related Occurrences
- Bedded Mn (Diagenesis)
- Bedded Mn (Low-T zeolite facies)
- Bedded Mn (High-T zeolite facies)
- Bedded Mn (Prehnite-Pumpellyite facies)
- Bedded Mn (Pumpellyite-Actinolite facies)
- Bedded Mn (Greenschist facies)
- Bedded Mn (Epidote-Amphibolite facies)
- Bedded Mn (Amphibolite facies)
- Bedded Mn (Albite-Epidote-hornfels facies)
- Bedded Mn (Hornblende-hornfels facies)
- Bedded Mn (Pyroxene-hornfels facies)