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Hata Formation (Imamura et al., 1958) Ministry of International Trade and Industry, 1967

Invalid synonym: Iruma Formation, Hata volcanic rocks, Hata Subgroup, Fukuyose Volcaniclastic Rocks, Kisa Volcaniclastic Rocks, Hosshoji Tuff, Kadou Volcaniclastic Rocks

• Type locality: Hata, Kakeya town, Unnan city, Shimane prefecture
• Volcanic rocks
• Kakeya Caldera fill deposits
• early Miocene (19.5 - 14.6 Ma, FT; 16.9 - 9.2 Ma, K-Ar; 18.3 Ma, U-Pb)
• Correlation: Koura Formation
• Intruded by: Uzuki Gabbro, Rhyolite dikes, Augite dolerite sills, Augite andesite sills

• Sedimentary facies: Terrestrial, Marine
• Sedimentary facies: Pyroclastic density current deposits
• Lithofacies (Upper): Dacite pumiceous lapilli tuff, Tuff
• Lithofacies (Lower, Upper): Breccia
• Lithofacies (Lower): Dacite lapilli tuff, Tuff
• Lithofacies (Lower, Minor): Breccia
• Lithofacies (Basal): Dacite lapilli tuff (Reworked deposits)
• Sedimentary structures: Eutaxitic
• Sedimentary structures (Lava): Palty joints, Lamp structure

• Thickness: 800 - 1,700 m
• Thickness (Upper): 900 m
• Thickness (Lower): 580 m
• Thickness (Basal): 260 m
• Upper limit: bottom of the felsic tuff bed
• Upper limit: Unconformity (Kawai Formation, Kuri Formation, Omori Formation, Noro Basalt)
• Lower limit: Unconformity (Toburodani Formation, Toriyago Metamorphic Rocks, Shimokuno Granite, Fube Granite, Neu Granite)

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

• Distribution: Hata - Nakaya, Unnan city, Shimane pref.; Mount Tenguyama - Mount Kyoragisan - Mount Otsujiyama - Hinami - Fukutomi - Hakutagawa river - Hosshojigawa river - Mount Kiyomizusan - Mount Dakesan, Yasugi city, Shimane pref.

• 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.)