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Kiwada Formation (Ueda, 1930) Nakajima and Watanabe, 2005

Invalid synonym: Takamizo Formation

• Type locality: hatake, Kiwada, Kimitsu city, Chiba prefecture
• Coherent formation
• Fore-arc basin sediments (Kazusa trough)
• early Pleistocene
• Contemporaneous heterotopic facies: Kurotaki Formation
• Correlation (Lower): Nojima Formation

• Sedimentary facies: Abyssal plain, lower Submarine fan, slope base of Submarine fan
• Depth of water: ca. 1,500 m (Foraminifera)
• Lithofacies: Mudstone, Sandy mudstone, Muddy sandstone
• Lithofacies (Minor): Turbidite
• Sedimentary structures: Slump structures, Sandstone dikes

• Thickness: ca. 51 - 720 m
• Upper limit: Bottom of O27
• Upper limit: Conformity (Otadai Formation), Unconformity (Daitozaki Shell Bed)
• Lower limit: Bottom of Kd38, Top of Oh1
• Lower limit: Conformity (Tomiya Formation)

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

• Distribution: hatake, Kiwada, Kimitsu city, Chiba pref.; Mutsuno - Daihara - Minato - Tomiya seashore, Futtsu city, Chiba pref.; Isumi city - Katsuura city - Otaki city, Chiba pref.; underground of Toshimaen park, Nerima-ku, Tokyo; underground of Tokyo Dome, Bunkyo-ku, Tokyo
• Fossils (Shellfishes): Ancistrolepis trochoideus, Fusitriton oregonensis, Halicardia sp.
• Fossils (Foraminifera): Pulleniatina sp.
• Fossils (Calcareous nannofossils): Calcidiscus macintyrei, Gephyrocapsa caribbeanica, Gephyrocapsa oceanica, Helicosphaera sellii, Reticulofenestra asanoi
• Fossils (Pollen): Alnus sp., Picea sp., Pinus sp., Taxodiaceae, Tsuga sp.
• Fossils (Trace fossils): Chondrites isp., Phoebichnus bosoensis, Phycosiphon isp., Planolites isp., Skolithos isp., Thalassinoides isp., Zoophycos isp.
• Tephra: Goshoyama (GS = Kd11)
• Tephra: Kd6, Kd7, Sr-Asn-Kd8, Kd9, HM-Kd16, Sr-Aki-Kd18, Kd18.5, Kd18.8, Kd19, Kd19.1, Kd19.2, Kd19.3, Kd19.5, Kd20, Kd20.3, Kd20.4, Sr-Kmd, Kd21, Kd21.5, Kd22, Kd22.1, Kd22.2, Kd22.3, Kd23, Kd23.5, Kd24, Kd25, Kd26, Kd27-1, Kd27-2, Kd28-1, Kd28-2, Kd28-3, Kd28-4, Kd28-5, Kd28-6, Kd28-7, Kd28-8, Kd28-9, Kd28-10, Kd29, Kd30, Kd31A, Kd31B, Kd32, Kd36, Kd38, Ho-Kd39, Kd40, Kd41, Kd42, Kd43, Kd44-Nk, Kd48, Kd48.1, Kd48.2

• Utsunomiya and Ooi (2019) Geology of the Kazusa-Ohara District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 127p. (in Japanese with English abstract 4p.)
• Tamura et al. (2019) Jour. Geol. Soc. Japan, vol.125, no.1, pp.23-39 DOI
• GSSP proposal group (2019) Jour. Geol. Soc. Japan, vol.125, no.1, pp.5-22 DOI
• Suzuki and Murata (2011) Jour. Geol. Soc. Japan, vol.117, no.7, pp.379-397 DOI
• Chiyonobu et al. (2007) Jour. Geol. Soc. Japan, vol.113, no.6, pp.223-232 DOI
• Nakajima and Watanabe (2005) Geology of the Futtsu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 102p. (in Japanese with English abstract 8p.)