Epidote-Amphibolite facies

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

Synonym

Epidote-Amphibolite subfacies of Greenschist facies, Upper greenschist subfacies

Index Minerals

Epidote, Hornblende

Required Geological Setting

Accretionary complexes + High-P metamorphic rocks

Accretionary complexes + Middle-P metamorphic rocks

Occurrence

Metamorphic rocks formed by regional metamorphism in the following condition: 500-700 degree and 0.6-1.2 GPa (20-40 km depth). A metamorphic facies formed in subduction zones. Epidote-Amphibolite facies metamorphic rocks are in Sanbagawa-type intermediate high-P metamorphic rocks.

Distribution of metamorphic rocks subjected to Epidote-Amphibolite facies regional metamorphism described in this site. Protolith of blue dots is bedded Mn deposit, and protoliths of green dots are igneous rocks and sedimentary rocks. Yellow zones are metamorphic belts.

Change of mineral assemblages

[ Extinct ] Serpentine
[ Appear ] Hornblende, Biotite, Oligoclase

Mineral Assemblages

[ Felsic Rocks ] Oligoclase/Albite, Quartz, Biotite, Epidote, Muscovite
[ Mafic Rocks ] Albite, Epidote, Hornblende/Actinolite
[ Ultramafic Rocks ] Tremolite, Talc, Diopside
[ Mudstone ] Muscovite, Chlorite, Oligoclase/Albite, Quartz, Spessartine, Biotite, Graphite
[ Laterite ]
[ Bedded Mn ] Quartz, Muscovite, Piemontite, Braunite, Spessartine, Albite
[ Carbonate Rocks ] Calcite/Dolomite, Quartz, Tremolite, (Wollastonite, Scapolite)

Localities

Asemi river (Piemontite)
Hitachi (Akazawa Formation)
Asahinata Mine (Talc)
Besshi

Related Occurrences

Other Occurrences