Amphibolite facies

Chemical Process (Solid-phase growth) - Middle-P metamorphic facies series

Index Minerals

Hornblende, Biotite, Andesine

Required Geological Setting

Accretionary complexes + Middle-P metamorphic rocks

Accretionary complexes + Low-P metamorphic rocks

Occurrence

Metamorphic rocks formed by regional metamorphism in the following condition: 500-800 degree and 0.2-0.8 GPa (5-30 km depth). A metamorphic facies formed in subduction zones. Epidote-Amphibolite facies metamorphic rocks are in Barrovian-type middle-P metamorphic rocks and Ryoke-type low-P metamorphic rocks.

Distribution of metamorphic rocks subjected to Amphibolite 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 ] Epidote
[ Appear ] Diopside, Andesine

Mineral Assemblages

[ Felsic Rocks ] Quartz, Andesine/Oligoclase/Albite, Biotite, Muscovite, (Hornblende/Actinolite)
[ Mafic Rocks ] Hornblende/Actinolite, Andesine/Oligoclase/Albite, (Garnet, Cummingtonite, Diopside, Biotite)
[ Ultramafic Rocks ] Tremolite, Chrysotile, Talc, Diopside
[ Mudstone ] Muscovite, Biotite, Quartz, Andesine/Oligoclase/Albite, Spessartine, (Hornblende/Actinolite, Kyanite/Sillimanite)
[ Laterite ] Muscovite, Biotite, Quartz, Andesine/Oligoclase/Albite, Staurolite, (Kyanite/Sillimanite)
[ Bedded Mn ]
[ Carbonate Rocks ] Calcite/Dolomite, Quartz, Tremolite, (Wollastonite, Scapolite)
[ Carbonate Rocks ](Higher grade) Calcite/Dolomite, Quartz, Diopside, (Wollastonite, Forsterite)