Inago Mine
Yadoriki, Matsuda city, Ashigara-Kami county, Kanagawa pref., Japan
Occurrence
Prehnite-Pumpellyite facies bedded manganese deposit
Tuff-hosted manganese deposit in basaltic to dacitic tuff of the early Miocene (17 Ma) Togatake Subgroup, the bottom member of the Tanzawa Group. The Togatake Subgroup has been subjected to Prehnite-Pumpellyite facies metamorphism by intrusion of the Tanzawa tonalite in the late Miocene (7 Ma). The Tanzawa Group is considered as the accreted Izu island arc. The Tanzawa tonalite is I-type (Magnetite-series). Approximately 4 km apart from quartz diorite, the heat source. Ages of sedimentary rocks were determined by microfossils, tonalite by radiometric dating.
Outcrop of tuff of the Togatake Subgroup at an old open pit of the low grade manganese mine. The reddish-brown host is Mn-bearing tuff, and reddish-brown color is due to pumpellyite-(Mn2+). The black crust on the surface is manganese dioxide formed by weathering of Mn-bearing tuff.
Reported Minerals
- Manganese dioxide
- Pumpellyite-(Mn2+)
Mineral Assemblages
- Pumpellyite-(Mn2+) - Manganese dioxide
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)