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Porosiri Ophiolite

Invalid synonym: Western zone of Hidaka Metamorphic Belt

• Low P/T metamorphic rocks
• Accreted oceanic crust
• Middle Cretaceous
• Protolith: Ophiolite

• Metamorphic facies: Greenschist, Amphibolite
• Metamorphic facies: 550 - 700 degree, 0.4 - 0.6 GPa
• Lithofacies (East): Meta-gabbro, Amphibolite (Gabbro origin, Sheet dyke origin), Meta-cumulate, Meta-dolerite
• Lithofacies (West): Greenschist, Pelitic schist, Epidote amphibolite, Green hornblende amphibolite, Meta-dolerite
• Lithofacies (Protolith): MORB
• Lithofacies (Protolith, East): Lower part of typical ophiolite sequence
• Lithofacies (Protolith, East): Gabbro, Sheet dyke, Dunite, Harzburgite, Wehrlite, Troctolite, Dolerite
• Lithofacies (Protolith, West): Upper part of typical ophiolite sequence
• Lithofacies (Protolith, West): Sandy and muddy sediments, Basalt (Pillow lava, Hyaloclastite), Dolerite

• Distribution (East-West): 1 - 4 km
• Distribution (South-North): ca. 70 km
• Upper limit: Hidaka Main Thrust (Hidaka Metamorphic Belt)
• Lower limit: Western Boundary Thrust (Idonnappu Belt)

------ Conformity, ~~~~~~ Unconformity, ~~~--- Local unconformity, '''/,, Interfingered, :::::: Fault, /--/-- Thrust, +__+__ Ground surface, ?--?-- Unknown

• Distribution: Shunbetsu river - Chiroro river - Futamatazawa river, Hidaka county, Hokkaido

• Nanayama et al. (2019) Jour. Geol. Soc. Japan, vol.125, no.6, pp.421-438 DOI
• Takahashi et al. (2018) Jour. Geol. Soc. Japan, vol.124, no.6, pp.399-411 DOI
• Tanaka et al. (2012) Jour. Geol. Soc. Japan, vol.118, no.11, pp.723-740 DOI
• Miyashita et al. (2007) Jour. Geol. Soc. Japan, vol.113, no.5, pp.212-221 DOI
• Niida and Takazawa (2007) Jour. Geol. Soc. Japan, vol.113, Supplement, pp.167-184 DOI
• Osanai et al. (2007) Jour. Geol. Soc. Japan, vol.113, Supplement, pp.29-50 DOI