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Kawai Formation Imamura et al., 1958

Invalid synonym: Oro Formation, Anami Formation, Nabeyama Formation, Lower Tamatsukuri Formation, Yonago Andesite

• Type locality: Kawai, Oda city, Saitama prefecture
• Coherent formation
• middle Miocene (20 - 12.4 Ma, K-Ar)
• Correlation: Josoji Formation

• Sedimentary facies: Shallow marine
• Sedimentary facies (Minor): Lacustrine
• Sedimentary facies: Coastal - Offshore
• Lithofacies: Sandstone
• Lithofacies (Minor): Andesite hyaloclastite, Volcanic breccia, Dacite submarine pyroclastic flow deposit, Rhyolite lava, Volcanic debris flow deposit, Tuffaceous sandstone, Mudstone, Siltstone
• Lithofacies (Bottom, Minor): Sandstone
• Sedimentary structures (Minor): Graded bedding, Reversed graded bedding

• Thickness: 0 - 400 m
• Upper limit: Interfinggered (Kuri Formation), Unconformity (Omori Formation)
• Lower limit: bottom of the felsic tuff bed
• Lower limit: Unconformity (Sada Formation, Hata Formation, Daito Granodiorite, Hiyodori Granite)

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

• Distribution: Gotsu city, Shimane, Shimane pref.; Kawai - Ushibara - Nima, Oda city, Shimane pref.; Shinji town - Tamatsukuri - Sudani, Matsue city, Shimane pref.; Munakata, Yonago city, Shimane pref.; Takakubo - Suga - Sannoji - Kitamura, Unnan city, Shimane pref.; Kisa town - Kadou town, Yasugi city, Shimane pref.
• Fossils: Plants (Leaves), Shellfishes (Freshwater), Fishes, Diatoms
• Fossils (Shellfishes): Anadara daitokudoensis, Cardium sp., Dosinia sp., Gastropods, Macoma sp., Patinopecten (Kotorapecten) yamasakiensis ninohesis, Venericardia sp., Vicarya cf. japonica, Vicaryella sp.
• Fossils (Foraminifera): Ammodiscus incertus, Bathysiphon sp., Cribrostomoides cf. crassimargo, Cyclammina cancellata, Cyclammina pusilla, Discammina compressa Gaudryina ishikiensis, Gaudryina yabei, Globobulimina sp., Hippocrepinella sp., Martinottiella communis, Plectina nipponica, Recurvoides sp., Reophar spp., Spirosigmoilinella compressa

• Kano et al. (2025) Geology of the Yonago District (2nd Ed.), Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 84p. (in Japanese with English abstract 4p.)
• Kano (2018) Jour. Geol. Soc. Japan, vol.124, no.10, pp.781-803 DOI
• Sawada et al. (2013) Jour. Geol. Soc. Japan, vol.119, no.4, pp.267-284 DOI
• Hayashi et al. (2013) Jour. Geol. Soc. Japan, vol.119, no.4, pp.300-311 DOI
• Sato et al. (2011) Jour. Geol. Soc. Japan, vol.117, no.8, pp.439-450 DOI
• Utada (2007) Jour. Geol. Soc. Japan, vol.113, no.8, pp.438-453 DOI
• Kano et al. (1994) Geology of the Matsue District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 126p. (in Japanese with English abstract 5p.)
• Kano et al. (1991) Geology of the Imaichi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 79p. (in Japanese with English abstract 5p.)