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Lower sequence

Synonym: Lower metamorphics

• Low P/T metamorphic rocks (0.7 GPa, 870 degrees Celsius)
• Protolith: Nakanokawa Group
• Metamorphism: Miocene (19 Ma, U-Pb)

• Metamorphic facies: Section of crust shallower than 23 km
• Metamorphic facies: Granulite, Amphibolite
• Lithofacies (Upper): Hornblende-biotite gneiss
• Lithofacies (Upper, Minor): Biotite gneiss, Hornblende amphibolite, Garnet-biotite gneiss
• Lithofacies (Middle): Hornblende amphioblite
• Lithofacies (Middle, Minor): Garnet-biotite gneiss, Gedrite-cordierite gneiss, Garnet amphibolite, Garnet-cordierite-biotite gneiss
• Lithofacies (Lower): Sandy - pelitic granulite (Garnet-orthopyroxene- cordierite gneiss, Garnet-cordierite-biotite gneiss), Medium - mafic granulite (Orthopyroxene geniss, Orthopyroxene amphibolite), Hornblende amphibolite
• Lithofacies (Protolith): MORB-type basaltic rocks
• Lithofacies (Protolith, Minor): Graywacke sandstone

• Distribution: Westerm part
• Lower limit: Thrust (Hidaka Main Thrust)

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

• Distribution: Menashunbetsu river, Urakawa city, Urakawa 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
• Osanai et al. (2007) Jour. Geol. Soc. Japan, vol.113, Supplement, pp.29-50 DOI