Pyrophyllite zone
Chemical Process (Alteration) - Open system under ground (Acidic metasomatism)
Index Minerals
Pyrophyllite
Required Geological Setting
Occurrence
Metasomatic zone formed by acidic hydrothermal fluid of 250-350 degree associated with Rhyolitic magma activities. This alteration is called pyrophyllitization. Protoliths are felsic rocks. Pyrophylllite zone may be associated with Moderately high-T hydrothermal deposits.
Distribution of Pyrophyllite zones described in this site. Yellow lines are volcanic fronts.
Change of mineral assemblages
- [ Extinct ] Natroalunite-2c (Minamiite), Dickite, Nacrite
- [ Appear ] Pyrophyllite, Diaspore
Mineral Assemblages
- Alunite, Pyrophyllite, Diaspore, Rutile, Quartz, Pyrite, Illite, Chlorite, (Anhydrite, Zunyite, Topaz)
Localities
- Momura (B rich)
- Kyonosawa (B rich)
- Shima Mine (B rich)
- Hinomaru-Nako Mine (P rich)
- Yoji Mine (Al,F rich)
- Shin-yo Mine (Al,F rich)
- Mount Kawate (Zunyite)
- Mount Shoko (Al rich)
- Nekoyama (Al rich)
- Mitsuishi (Al rich)
- Isshiki Mine (Al rich)
- Toho Mine (Al rich)
- Hongo Mine (Sulfide deposit)
- Masutomi Mine (Sulfide 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)