Blueschist facies

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

Synonym

Graucophane-schist facies

Index Minerals

Glaucophane, Lawsonite, Aragonite

Required Geological Setting

Accretionary complexes + High-P metamorphic rocks

Serpentine mélange

Occurrence

Metamorphic rocks formed by regional metamorphism in the following condition: 200-500 degree and 0.6-1.2 GPa (20-40 km depth). A metamorphic facies formed in subduction zones. Blueschist facies metamorphic rocks are in Franciscan-type high-P metamorphic rocks.

Distribution of metamorphic rocks subjected to Blueschist facies regional metamorphism described in this site. Protoliths of green dots are igneous rocks and sedimentary rocks. Yellow zones are metamorphic belts.

Change of mineral assemblages

[ Extinct ] Zeolites, Pumpellyite, Actinolite, Calcite
[ Appear ] Glaucophane, Lawsonite, Aragonite

Mineral Assemblages

[ Felsic Rocks ] Quartz, Jadeite/Albite, Lawsonite, Phengite/Paragonite, Chlorite, (Glaucophane/Riebeckite)
[ Mafic Rocks ] Glaucophane/Riebeckite, Lawsonite, Chlorite, Jadeite/Albite, (Epidote, Phengite/Paragonite, Omphacite)
[ Ultramafic Rocks ] Serpentine (Antigorite), Brucite, Zoisite, (Talc)
[ Mudstone ] Phengite/Paragonite, Jadeite/Albite, Chlorite, Zoisite, Quartz
[ Laterite ] Kyanite, Phengite/Paragonite, Chlorite, Jadeite/Albite, Quartz, (Pargasite)
[ Bedded Mn ]
[ Carbonate Rocks ] Aragonite, Quartz