[ Top ] [ Japanese ]

Upper sequence

Synonym: Upper metamorphics

• Low P/T metamorphic rocks (0.7 GPa, 870 degrees Celsius)
• Protolith: Nakanokawa Group
• Metamorphism: Eocene - Oligocene (40 - 30 Ma, K-Ar; 39.6 Ma, U-Pb; 55 Ma, Rb-Sr)

• Metamorphic facies: Section of crust shallower than 23 km
• Metamorphic facies: Amphibolite, Greenschist
• Lithofacies (Upper, East): Meta-sedimentary rocks, Hornfels, Biotite-muscovite-chlorite schist
• Lithofacies (Lower, West): Biotite-muscovite gneiss, Biotite-muscovite schist
• Lithofacies (Protolith): Graywacke sandstone, Pelitic rocks, (Mafic rocks are not included.)

• Distribution: Eastern part
• Upper limit: Transitional (Nakanokawa Group)

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

• Distribution: Shoya, Erimo city, Horoizumi 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