Metasomatic sulphur deposit
Chemical Process (Alteration) - Open system under ground (Acidic metasomatism)
Synonym
Metasomatic sulfur deposit, Impregnated metasomatic sulphur deposit, Impregnated metasomatic sulfur deposit
Required Geological Setting
Occurrence
Sulphur deposit associated with Rhyolitic magma activities. Sulphur replaces dacite to andesite lava. Deposits are layered to massive form in lava flows, and covered with younger lava flows. Deposits are associated with various acidic metasomatc rocks. Plagioclase and mafic minerals such as pyroxenes, hornblende, and forsterite in the host rock are dissolved away. A part of Fe in pyroxenes and hornblende are combined with sulphur to be pyrite and/or marcasite.
Distribution of Metasomatic sulphur deposits described in this site. Yellow lines are volcanic fronts.
Mineral Assemblages
- Sulphur, Pyrite, Marcasite, Alunite, Cristobalite, Quartz, (Baryte)
Localities
- Ishizu Mine
- Agatsuma Mine
- Shirane Mine
- Numajiri Mine
- Jigoku Pond (Sulphur)
- Noboribetsu-Jigoku Valley (Sulphur)
Related Occurrences
- Halloysite zone (Alunite zone, Argillized zone)
- Kaolinite zone (Alunite zone, Argillized zone)
- Minamiite-Alunite zone (Alunite zone)
- Pyrophyllite zone