Halloysite zone
Chemical Process (Alteration) - Open system under ground (Acidic metasomatism)
Synonym
Alunite zone (Low temperature), Argillized zone (Halloysite)
Index Minerals
Halloysite
Required Geological Setting
Occurrence
Metasomatic zone formed by acidic hydrothermal fluid of 50-100 degree associated with Rhyolitic magma activities. This alteration is called halloysitization and is a part of alunitization or argillization. Protoliths are felsic rocks. Halloysite zone may be associated with Hydrothermal Au-Ag deposits or Hot spring deposits.
Distribution of Halloysite zones described in this site. Yellow lines are volcanic fronts.
Change of mineral assemblages
- [ Appear ] Alunite, Halloysite, Pyrite
Mineral Assemblages
- Alunite, Halloysite, Cristobalite, Pyrite, Smectite, (Gypsum)
Localities
- Joshin Mine (Halloysite deposit)
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)