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Upper Nanakura Tuff Member Chitani, 1928

• Type locality: Nibunanai river, Futatsui town, Noshiro city, Akita prefecture
• Volcanic rocks
• Pliocene - Pleistocene

• Lithofacies: Pyroxene-bearing hornblende biotite rhyolite
• Lithofacies (Upper): Interbedded sandy tuff and mudstone
• Lithofacies (Middle): Hornblende-bearing biotite dacite - rhyolite
• Lithofacies (Middle): Pumiceous tuff, Sandy - silty tuff
• Lithofacies (Lower): Interbedded sandy tuff and mudstone
• Lithofacies (Minor):Acidic lapilli tuff, Acidic tuff breccia

• Thickness: 0 - 600 m
• Host: Funakawa Formation, Fujikotogawa Formation
• Lower limit: Interfingered (Main part)

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

• Distribution: Futatsui town, Noshiro city - Fujisato city, Yamamoto county, Akita pref.; Nibunanai river, Futatsui town, Noshiro city, Akita pref.

• Murakami et al. (2008) Jour. Geol. Soc. Japan, vol.114, Supplement, pp.111-120 DOI
• Ozawa et al. (1985) Geology of the Moritake District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 69p. (in Japanese with English abstract 5p.)
• Ozawa et al. (1984) Geology of the Noshiro District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 91p. (in Japanese with English abstract 9p.)
• Hirayama and Sumi (1963) Takanosu, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 90p. (in Japanese with English abstract 7p.)