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Futaba Group

• Type locality: Futaba county, Fukushima prefecture
• Coherent formation
• southern Yezo Forearc basin (Jobanoki basin)
• Late Cretaceous, Coniacian - Santonian (Ammonoids, Inoceramus)

• Sedimentary facies: Terrestrial, Marine
• Sedimentary facies: small scale alluvial fan facing the sea, Alluvial plain, Continental shelf
• Sedimentary facies: Talus, Alluvial fan, Meandering river, Braided river, Shoreface - Inner shelf
• Lithofacies (Main): Sandstone
• Lithofacies (Minor): Mudstone, Conglomerate

• Thickness: ca. 300 - 350 m
• Area: 15 km from north to south, 2 - 3 km from east to west
• Upper limit: Unconformity (Shiramizu Group, Sodetamayama Formation)
• Lower limit (West): Unconformity (Obisagawa Granodiorite)
• Lower limit (Southwest): Unconformity (Takakurayama Group)

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

• Distribution: Tamayama, Yotsukura town, Iwaki city, Fukushima pref.; Osaka, Naraha city, Futaba county, Fukushima pref.; Kotakidaira, Kamiasamigawa, Hirono city, Futaba county, Fukushima pref.
• Fossils: Ammonoids, Inoceramus

• Ando et al. (2011) Jour. Geol. Soc. Japan, vol.117, Supplement, pp.49-67 DOI
• Kubo et al. (2002) Geology of the Kawamae and Ide District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 136p. (in Japanese with English abstract 6p.)
• Iwao and Matsui (1961) Taira and Kawamae, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 103p. (in Japanese with English abstract 17p.)