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Taga Group (Makiyama, 1920) Ando et al., 2011

Kokozura Formation is recognized as a member of Takaku Group, and the upper part of Taga Group is separated as Hitachi Group.

Invalid synonym: Taga Formation, Urizura Formation, Isozaki Formation, Mito Formation, Joban Formation, Genjigawa Group

• Coherent formation
• southern Yezo Forearc basin (Jobanoki basin)
• middle Miocene (15 - 9 Ma)

• Sedimentary facies: Marine
• Sedimentary facies: Shelf - Upper continental slope
• Sedimentary facies: Submarine channel-fill deposit, Submarine slump scar-fill deposit
• Lithofacies: Diatomaceous siltstone, Calcareous sandstone
• Lithofacies (Minor): Tuff

• Thickness: ca. 50 - 330 m
• Upper limit: Unconformity (Dainenji Formation, Sodetamayama Formation, Terushima Formation, Yotsukura Formation, Sukegawa Formation, Kume Formation, Hanareyama Formation, Kamiizumi Formation)
• Lower limit: Unconformity (Takaku Group, Shirado Group, Kunugidaira Formation, Shiramizu Group, Oarai Formation)

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

• Distribution: Hisanohama bay, Hisanohama village, Iwaki city, Fukushima pref.; Yotsukura town, Iwaki city, Fukushima pref.; Yusuji seashore, Hirono city, Futaba county, Fukushima pref.; Cape Kunosaki, Hirakata village, Kitaibaraki city, Ibaraki pref.; Otsu village, Kitaibaraki city, Ibaraki pref.: Namekawa village - Ayukawa ?, Hitachi city, Ibaraki pref.
• Fossils: Echinoids, Sponges (Spicules, Makiyama chitanii), Diatoms, Radiolarians, Dinoflagelates, Calcareous nannofossils
• Fossils (Shellfishes): Acila submirabilis, Lucinoma acutilineata, Macoma sp., Portlandia sp.
• Fossils (Foraminifera): Dentalina? sp., Discorbis? sp., Epistomina elegans, Globorotalia tumida, Lagena globosa, Lagena striata, Nodosaria insecta, Nonion pompilioides, Orbulina universa, Pullenia bulloides, Robulus limbosus, Robulus pseudorotulatus, Sphaercidina austriaca, Uvigerina subperegrina
• Tephra: Ayukawa Tephra, Izura Tephra

• 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.)
• Kubo et al. (1994) Geology of the Namie and Iwaki-Tomioka District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 104p. (in Japanese with English abstract 7p.)
• Sakamoto et al. (1972) Geology of the Nakaminato District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 94p. (in Japanese with English abstract 5p.)
• 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.)