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Ryubasan Andesites

• Voclanic rocks
• middle Miocene

• Lithofacies: Andesite hyaloclastite
• Lithofacies (Minor): Volcanic breccia, Tuff breccia, Lapilli tuff, Tuff, Mudstone, Sandstone

• Upper limit: Bottom of the intermediate volcanic rocks-bearing horizon
• Upper limit: Conformity (Taya Tuff Member, Kyunozoki Tuff Member, Nakada Tuff and Mudstone Member)
• Lower limit: Conformity (Sotosawa Mudstone Member)

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

• Distribution: Yamagata pref.

• Ozawa and Sumi (1961) Uzenkaneyama, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 66p. (in Japanese with English abstract 5p.)