Greenschist facies
Chemical Process (Solid-phase growth) - Middle-P metamorphic facies series
Index Minerals
Epidote, Actinolite, Muscovite
Required Geological Setting
Accretionary complexes + High-P metamorphic rocks
Accretionary complexes + Middle-P metamorphic rocks
Accretionary complexes + Low-P metamorphic rocks
Occurrence
Metamorphic rocks formed by regional metamorphism in the following condition: 350-500 degree and 0.2-1.2 GPa (5-30 km depth). A metamorphic facies formed in subduction zones. Greenschist facies metamorphic rocks are in Sanbagawa-type intermediate high-P metamorphic rocks, Barrovian-typ middle-P metamorphic rocks, and in Ryoke-type low-P metamorphic rocks.
Distribution of metamorphic rocks subjected to Greenschist facies regional metamorphism described in this site. Protolith of blue dots is bedded Mn deposit, protolish of red dots is serpentinite, and protoliths of green dots are igneous rocks and sedimentary rocks. Yellow zones are metamorphic belts.
Change of mineral assemblages
- [ Extinct ] Illite, Pumpellyite, Zeolites
- [ Appear ] Muscovite, Actinolite/Tremolite, Spessartine
Mineral Assemblages
- [ Felsic Rocks ] Albite, Quartz, Epidote, Muscovite, (Stilpnomelane)
- [ Mafic Rocks ] Chlorite, Albite, Epidote, Actinolite
- [ Ultramafic Rocks ] Clinochlore, Serpentine (Antigorite), Brucite, Diopside, (Talc, Actinolite/Tremolite, Clinozoisite)
- [ Mudstone ] Muscovite, Chlorite, Albite, Quartz, Spessartine, Graphite
- [ Laterite ] Chloritoid, Chlorite, Muscovite/Paragonite, Quartz
- [ Bedded Mn ] Quartz, Muscovite, Piemontite, Braunite, Spessartine, Albite
- [ Carbonate Rocks ] Calcite/Dolomite, Quartz, (Talc, Tremolite)
Localities
- Kami-Nagatoro (Stilpnomelane, High-P)
- Banjo (Glaucophane, High-P)
- Yamabuki creek (Hematite, High-P)
- Yoshimi (Zeolite, High-P)
- Kami-Suwa (Chloritoid, Middle-P)
- Takarayama Mine (Quartz, Middle-P)
Related Occurrences
- Albite-Epidote-hornfels facies
- Hornblende-hornfels facies
- Pyroxene-hornfels facies
- Sanidinite-hornfels facies
- Pumpellyite-Actinolite facies
- Blueschist facies
- Epidote-Amphibolite facies
- Eclogite facies
- Ultrahigh-pressure faices