Sessho Creek
Hoshimata, Tsumagoi city, Agatsuma county, Gunma pref., Japan
Synonym
Sesshozawa
Occurrence
Acidic metasomatic rocks of Minamiite-Alunite zone
Alunite deposit of alunitization alteration by volcanic gas in andesite of the early Pliocene Takai Volcanic Rocks.
Outcrop of andesite subjected to alunitization alteration by volcanic gas. The gray host is andesite of Takai Volcanic Rocks. The andesite turns gray by alunitization. The white veins around the coin is alunite. Brown dirts on the outcrop is limonite crusts formed by oxidation of pyrite in altered andesite.
Reported Minerals
- Minamiite
- Huangite
- Alunite
- Natroalunite
- Sulphur
- Pyrite
- Crandallite
- Woodhouseite
Mineral Assemblages
- Alunite - Natroalunite - Minamiite - Huangite - Sulphur - Pyrite
- Andesite(Host) - Sulphur
- Andesite(Host) - Pyrite
Localities
- Sessho creek (Vein type)
- Funabara mountain pass (Replaced type)
- Ukusu Mine (Replaced type)
Related Occurrences
- Halloysite zone (Alunite zone, Argillized zone)
- Kaolinite zone (Alunite zone, Argillized zone)
- Minamiite-Alunite zone (Alunite zone)
- Pyrophyllite zone
- Smectite zone (Argillized zone)
- Interstratified mineral zone (Argillized zone)
- Illite-Chlorite zone (Propylite zone)
- Epidote-Actinolite zone
- Stilbite-Mordenite zone (Zeolite zone)
- Heulandite-Analcime zone (Zeolite zone)
- Laumontite-Albite zone (Zeolite z., Propylite z.)
- Wairakite-Albite zone (Zeolite zone)