Kinjo Mine
Kakino, Yamagata city, Gifu pref., Japan
Occurrence
Moderately high-T hydrothermal skarn deposit
Skarn formed by the early Paleocene (65 Ma) Koka Granite intruded in the Middle Jurassic (170 Ma) Nabi unit, a member of the Tamba-Mino-Ashio accretionary complex. The moderate temperature hydrothermal deposit associated with skarn was formed by the quartz porphyry and granodiorite porphyry arc-shaped dikes of the Okumino Rhyolites. Various arsenate minerals were reported from the oxidation zone. The Koka Granite is I-type (Magnetite-series), and approximately 1 km apart from this locality. The sulfide deposits are in contact with the quartz porphyry and the granodiorite porphyry dikes. The age of limestone is probably Permian (270 Ma). The Arc-shaped dikes and the Koka Granite are considered as members of the Cretaceous Horado Caldera Complex. Ages of sedimentary rocks were determined by radiolarians, and granite by K-Ar radiometric dating.
![Kinjo Mine](kinjoGIFU.jpg)
Adit on the skarn outcrop in the Nabi Unit. There are outcrops of fresh Permian limestones around this adit. Various arsenate secondary minerals were recovered from the dump. There are a lot of leeches in this locality.
Reported Minerals
- Galena
- Sphalerite
- Pyrite
- Chalcopyrite
- Arsenopyrite
- Greenockite
- Tyrolite
- Adamite
- Aurichalcite
- Cerussite
- Linarite
- Hemimorphite
- Scorodite
- Mimetite
- Pharmacosiderite
- Olivenite
- Hedenbergite
- Grossular
- Epidote
- Tremolite
- Axinite
- Quartz
Mineral Assemblages
- Chalcopyrite - Tyrolite
- Chalcopyrite - Adamite - Olivenite
History
- The deposit was found during Edo period (1600-1850).
- Around 1850: Mr. Ishigami mined the deposit.
- Around 1910: Mr. Kanno mined the deposit.
- 1914: Ceased to mine.
Localities
- Kinjo Mine (Arsenate)