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Okuhida Pyroclastic Flow Deposit Harayama, 1987

Invalid synonym: Momisawa Pyroclastic Flow Deposit, Momisawadake Dacite Tuff, Iwatsuboyama Welded Tuff

• Type locality: Mount Momisawadake, Takayama city, Gifu prefecture - Omachi city, Nagano prefecture
• Tephra
• middle Pleistocene (0.68 Ma, FT; 0.4 Ma, K-Ar)
• Correlation: Omachi APm Tephra, Kumonotaira Gravel Bed

• Lithofacies: Augite hypersthene hornblende biotite rhyolite - dacite welded tuff
• Sedimentary structures: Eutaxitic structure

• Source: Suiendani Vent
• Thickness: a few dozen - 200 m
• Area (Present): ca. 5 km²
• Area: ca. 70 km² or wider
• Volume: ca. 10 km³ or larger
• Upper limit: Unconformity (Odana Lava)
• Lower limit: Unconformity (Nyukawa Pyroclastic Flow Deposit, Kasagatake Rhyolites)

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

• Distribution: Mount Momisawadake - Nishikama ridge, Takayama city, Gifu pref.; - Omachi city, Nagano pref.; Kasadani valley - Mount Yumioridake - Kamatagawa river - Mount Nakasakiyama - Nabedaira - Yunosako ridge - Mount Iwatsuboyama - Raicho ridge - Imami - Fukuji, Okuhidaonsengo, Takayama city, Gifu pref.

• Harayama et al. (1991) Geology of the Yarigatake District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 190p. (in Japanese with English abstract 8p.)
• Harayama (1990) Geology of the Kamikochi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 175p. (in Japanese with English abstract 11p.)
• Kato et al. (1989) Geology of the Omachi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 111p. (in Japanese with English abstract 7p.)