Osanai Tuff Member

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Osanai Tuff Member (Inoue, 1960) Usuda et al., 1979

Invalid synonym: Osanai Member

Volcanic rocks
Marginal facies of lava dome of Yonegamori Dacite
Miocene

Sedimentary facies: Marine
Sedimentary facies (Partly): Submarine pyroclastic flow deposit
Lithofacies: Dacitic pumice tuff, Tuff breccia, Lapilli tuff
Lithofacies (Minor): Tuffaceous sandstone

Lower limit: Conformity (Onnagawa Formation)

Funakawa Formation (Kariwano , Akita pref.)
[ Upper ]
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Osanai Tuff Member / Yonegamori Dacite
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[ Lower ]

Oga peninsula, Akita pref.
[ Upper ]
~~~~~~~~~~~~~~
Shibikawa Formation
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Wakimoto Formation
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Kitaura Formation
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Nishimizuguchi Formation
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Minamihirasawa Formation
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Funakawa Formation
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[ Lower ]

Oga peninsula - Dewa hills, Akita pref.
[ Upper ]
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Sasaoka Formation
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Tentokuji Formation
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Funakawa Formation
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[ Lower ]

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

Distribution: Yonegamori - Chojamori - Hatayama, Kyowa, Daisen city, Akita pref.

Tsuchiya and Yoshikawa (1994) Geology of the Kariwano District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 72p. (in Japanese with English abstract 4p.)