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Katsurabuchi Formation Inoue, 1960

• Type locality: Iriminai river, Katsurabuchi, Nishinagano, Kakunodate town, Senboku city, Akita prefecture
• Volcanic rocks
• early Miocene (21.8 Ma, U-Pb, 19.0 Ma, FT)
• Correlation: Kitanomatasawa Formation (as Okuramata Formation)

• Lithofacies: Pumice volcanic lapilli tuff, Pumice tuff breccia, Tuff
• Lithofacies (Minor): Conglomerate
• Sedimentary structures (Conglomerate): Graded bedding, Trough cross-stratification

• Thickness: ca. 1,500 m or thinner
• Upper limit: Unconformity (Yamaya Formation), Abut unconformity (Shiotezawa Formation)
• Lower limit: Abut unconformity (Yamayakawa Formation)

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

• Distribution: Iriminai river, Katsurabuchi, Nishinagano, Kakunodate town, Senboku city, Akita pref.; Shizukuda, Kawaki, Yamaya, Kakunodate town, Senboku city, Akita pref.

• Hosoi et al. (2019) Jour. Geol. Soc. Japan, vol.125, no.4, pp.279-295 DOI