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Kenjaku Member Ooi and Yokoyama, 2011

Invalid synonym: upper Kamiiwahashi Formation, middle Miwa Formation

• Type locality: Kenjaku, Ibaraki city, Higashiibaraki county, Ibaraki prefecture
• Coherent formation
• Pleistocene

• Sedimentary facies: Marine
• Sedimentary facies: Submarine canyon fill deposit
• Lithofacies (Upper): Silt
• Lithofacies (Basal): Conglomerate
• Sedimentary structures (Sandstone): Hummocky cross-stratification
• Sedimentary structures (Interbedded sandstone and mudstone): Lenticular stratification

• Thickness: ca. 5 - 35 m
• Thickness (Gravels): ca. 6.5 - 13 m
• Upper limit (Northernmost): Conformity (Joso Formation)
• Upper limit: Unconformity (Namegata Member)
• Lower limit: Unconformity (Yokota Formation, Kiyokawa Formation, Yabu Formation, Kamiizumi Formation)

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

• Distribution: Namegata terrace, Higashi-Ibaraki terrace, Lake Hinuma, Naka terrace, Ibaraki pref.
• Distribution: Hongo - Kenjaku, Ibaraki city, Higashiibaraki county, Ibaraki pref.; Onuki town - Kamiyama - Matsukawa, Oarai city, Higashiibaraki county, Ibaraki pref.
• Fossils: Oysters
• Tephra: ArP (Araya Pumice Bed = Nk-Yt), OiP (Oiwata Pumice Bed = Nk-Nm), Br-Sc, Bk-Sc, Ob (= TAu-9), Med, TAu-11

• Ooi et al. (2013) Jour. Geol. Soc. Japan, vol.119, no.7, pp.488-505 DOI
• Ooi and Yokoyama (2011) Jour. Geol. Soc. Japan, vol.117, Supplement, pp.103-120 DOI
• Sakamoto et al. (1981) Geology of the Ishioka District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 50p. (in Japanese with English abstract 3p.)
• Sakamoto (1975) Geology of the Isohama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 55p. (in Japanese with English abstract 4p.)
• 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.)