Kusama Mine
Shimobe, Minobu city, Minami-Koma county, Yamanashi pref., Japan
Synonym
Shimobe Mine
Occurrence
High-T zeolite facies bedded manganese deposit
Cu-Mn deposit in mudstone of the late Miocene (11 Ma) Shimobe Formation, the bottom member of the Fujikawa Group. The deposit is at the boundary between mudstone and upper basaltic pyroclastics. The deposit has been subjected to Zeolite facies metamorphism. The Fujikawa group can be interpreted as sediments at the back-arc basin of the old Izu-Ogasawara arc. Ages of sedimentary rocks were determined by microfossils.
Outcrop of mudstone of the Shimobe Formation near an adit. The adit is at the boundary between mudstone and basaltic lava. This deposit was classified to bedded manganese deposit here, although this can be a sediment-hosted copper deposit. This mine is generally known as copper mine but there is a record that this mine was developed for copper.
Reported Minerals
- Hausmannite
- Caryopilite
- Rhodochrosite
- Braunite
- Bustamite
- Piemontite
- Baryte
- Hematite
- Copper
- Laumontite
- Stilbite
- Mordenite
- Chalcopyrite
- Malachite
Mineral Assemblages
- Hausmannite - Rhodochrosite - Caryopilite
- Hematite - Bustamite - Piemontite
- Hematite - Copper
- Hematite - Chalcopyrite - Malachite
Localities
- Kusama Mine (Mudstone-hosted, Miocene)
- Kiyokawa Mine (Chichibu belt)
- Okutama Mine (Chichibu belt)
- Shiromaru Mine (Braunite, Chichibu belt)
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)