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Yoneyama Formation Yoneyama Research Group, 1967

• Type locality: Tanne river, Kashiwazaki city, Niigata prefecture
• Volcanic rocks
• Volcanic edifice
• early - late Pliocene (2.75, 2.48 Ma, K-Ar)
• Contemporaneous heterotopic facies: upper Takegahana Formation
• Interfingered (Upper): upper Tamugigawa Formation
• Correlation: middle Nishiyama Formation, Kurohime Formation, Hachikokusan Formation
• Intruded by: Tanne Intrusive Rock

• Sedimentary facies: Marine
• Sedimentary facies: Submarine lava dome
• Lithofacies: Olivine-bearing pyroxene andesite, Pyroxene andesite, Hornblende pyroxene andesite
• Lithofacies: Lava (Feeder dike, Hyaloclastite), Volcanic breccia, Volcanic conglomerate, Tuff breccia, Lapilli tuff, Tuff
• Lithofacies (Minor): Mudstone, Sandstone, Volcanic sandstone, Volcanic conglomerate

• Thickness: 400 - 2,000 m
• Upper limit: Unconformity (Omigawa Formation, Komanoma Formation, Higher Terrace Deposit, Kume Conglomerate)
• Lower limit: Unconformity (Oshimizu Formation, Ogaya Formation)

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

• Distribution: Tanne river - Banjin - Yoneyamadai - Benten island - Cape Kamomegahana - Omigawa - Agewa - Kasajima - Harai river, Kashiwazaki city, Niigata pref.; Mount Okami, Joetsu city, Niigata pref.
• Fossils: Shellfishes

• Takeuchi et al. (1996) Geology of the Kakizaki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 48p. (in Japanese with English abstract 5p.)
• Kobayashi et al. (1995) Geology of the Kashiwazaki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 102p. (in Japanese with English abstract 4p.)
• Kobayashi et al. (1989) Geology of the Okanomachi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 112p. (in Japanese with English abstract 5p.)