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Yotsuzawa Formation Kitamura et al., 1972
Invalid synonym: Okunosawa Formation, Yotsuzawa Tuff
- Type locality: Yotsuzawa creek, Sakuta river, Shichinohe city, Kamikita county, Aomori prefecture
- Volcanic rocks
- Miocene (Nishikurosawa stage, Foraminifera)
- Correlation: Itadome Formation?
- Metamorphic facies: Zeolite (Laumontite)
- Lithofacies: Andesitic - dacitic volcanic breccia, tuff breccia, Dacitic pumice tuff
- Lithofacies (Minor): Dacitic tuff, Rhyolite lava, Andesite lava
------ Conformity, ~~~~~~ Unconformity, ~~~--- Local unconformity, '''/,, Interfingered, :::::: Fault, /--/-- Thrust, +__+__ Ground surface, ?--?-- Unknown
- Distribution: Yotsuzawa creek, Sakuta river, Shichinohe city, Kamikita county, Aomori pref.; Asamushi, Aomori city, Aomori pref.; Sotodoji, Hiranai city, Higashitsugaru county, Aomori pref.; Nishinosawa creek, Shimizu river, Hiranai city, Higashitsugaru county, Aomori pref.; Ogawame creek, Takizawa, Aomori city, Aomori pref.
- Fossils (Foraminifera): Globigerina angustiumbilicata, Globoquadirina altisoira, Globorotalia (Turborotalia) praeschtula
- Uemura (1983) Geology of the Asamushi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 40p. (in Japanese with English abstract 4p.)