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Sanzugawa Formation Kato and Shimada, 1953

• Coherent formation
• Pliocene
• Correlation: Funakawa Formation
• Intruded by: Dacite

• Sedimentary facies: Lacustrine
• Lithofacies (Upper Member): Tuffaceous siltstone, Tuff
• Lithofacies (Main Member): Tuffaceous sandstone, Tuffaceous siltstone, Interbedded conglomerate and pumice tuff, Tuff
• Lithofacies (Breccia Member): Andesite tuff breccia

• Thickness: 200 - 400 m
• Upper limit: Unconformity (Bosawa Andesite, Kawaiyama Dacite)
• Lower limit: Unconformity (Kamuroyama Granites, Yunosawagawa Formation, Innai Tuff Member, Torakeyama Formation)

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

• Distribution: Sanzu river, Takamatsu river - Oyasu - Akinomiya - Hirajo - Otsubechi - Asahagi - Terasawabashi - Kabayama, Yuzawa city, Akita pref.
• Fossils (Plants): Abies sanzugawaensis, Acer palaeodiabolicum, Acer subukurunduense, Alnus protohirsuta, Alnus protomaximowiczii, Alnus subfirma, Betula miomaximowicziana, Betula onbaraensis, Castanea miocenata, Cercidiphyllum crenatum, Clethra maximowiczii, Cryptomeria miyataensis, Fagus palaeocrenata, Fagus protojaponica, Fraxinus sanzugawaensis, Juglans japonica, Kalopanax acerifolius, Lonicera protojaponica, Osmunda cf. japonica, Picea ugoana, Populus aizuana, Populus sanzugawaensis, Prunus protossiori, Pterocarya asymmetorosa, Quercus miocrespula, Rhamnus protocrenata, Rhamnus sanzugawaensis, Rhododendron minasense, Rhododendron sanzugawaense, Salix akitaensis, Salix hokkaidoensis, Salix k-suzukii, Salix muraii, Salix sanzugawaensis, Sorbus palaeojaponica, Sorbus uzenensis, Thuja nipponica, Tilia protojaponica, Tsuga miyataensis, Ulmus protojaponica, Weigela sanzugawaensis, Zelkova ungeri

• Takashima and Koshiya (2008) Jour. Geol. Soc. Japan, vol.114, Supplement, pp.97-109 DOI
• Ozawa et al. (1979) Geology of the Yuzawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 64p. (in Japanese with English abstract 4p.)
• 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.)