Pumpellyite-Actinolite facies

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

Synonym

Pumpellyite-Actinolite subfacies of greenschist facies, Lower greenschist subfacies

Index Minerals

Pumpellyite, Actinolite

Required Geological Setting

Accretionary complexes + High-P metamorphic rocks

Occurrence

Metamorphic rocks formed by burial or regional metamorphism in the following condition: 200-350 degree and 0.4-0.6 GPa (15-20 km depth). A metamorphic facies formed in the lower part of oceanic crusts near mid-ocean ridges or in subduction zones. Pumpellyite-Actinolite facies metamorphic rocks are in accretionary complexes near the boundaries of Franciscan-type and Sanbagawa-type high-P metamorphic rocks.

Distribution of metamorphic rocks subjected to Pumpellyite-Actinolite 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 distribution of high-P metamorphic belts.

Change of mineral assemblages

[ Extinct ] Prehnite, Zeolite, Celadonite, Illite/Smectite, Caryopilite, Hausmannite
[ Appear ] Actinolite/Tremolite, Pumpellyite, Albite, Epidote, Illite/Chlorite, Antigorite, Talc

Mineral Assemblages

[ Felsic Rocks ] Quartz, Illite/Chlorite, Albite, Pumpellyite, Epidote, (Stilpnomelane)
[ Mafic Rocks ] Illite/Chlorite, Albite, Pumpellyite, Actinolite, Epidote, (Calcite)
[ Ultramafic Rocks ] Clinochlore, Serpentine (Chrysotile, Lizardite), Talc, Actinolite/Tremolite, (Clinozoisite)
[ Mudstone ] Illite/Chlorite, Albite, Quartz, Graphite
[ Laterite ]
[ Bedded Mn ] Braunite, Quartz, Spessartine, Piemontite, Muscovite
[ Carbonate Rocks ] Calcite/Dolomite, Quartz, (Talc, Tremolite)

Localities

Kosugi (Lawsonite)
Asahine (Pumpellyite)
Kaiya (Omphacite)
Mount Nyukasa (Omphacite)

Related Occurrences

Other Occurrences