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Nanakita Formation Nakamura, 1941 ex Kitamura et al., 1983

• Type locality: Nanakita river, Rifu city, Miyagi county - Nanakita - Neshiroishi, Izumi ward, Sendai city, Miyagi prefecture
• Coherent formation
• late Miocene (Diatoms)
• Contemporaneous heterotopic facies: Omatsuzawa Formation
• Correlation: Tsunaki Formation
• Intruded by: Nanatsumori Lava

• Sedimentary facies: Shallow marine
• Lithofacies (Upper): Sandstone
• Lithofacies (Lower): Interbedded sandstone and pumice tuff
• Lithofacies (Lower, Minor): Conglomerate
• Lithofacies (Minor): Siltstone, Tuff, Conglomerate
• Sedimentary structures: Cross stratification, Bioturbation

• Thickness: 50 - 200 m or thicker
• Upper limit: Bottom of the tuff-dominant horizon
• Upper limit: Conformity (Shirasawa Formation), Unconformity (Arakawa Pyroclastic Rocks, Miyatoko Tuff Member, Kameoka Formation)
• Lower limit (Aoso Formation): Top of K8
• Lower limit: Conformity (Aoso Formation, Otsutsumi Formation), Abut unconformity (Sauramachi Formation)

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

• Distribution: Nanakita - Neshiroishi, Izumi ward, Sendai city, Miyagi pref.; Tomiya, Tomiya city, Miyagi pref.; Rifu city, Miyagi county, Miyagi pref.
• Fossils: Shellfishes (Mercenaria? sp., Miyagipecten matsumoriensis), Brachiopods (Terebulatulina sp.), Foraminifera (Globorotalia conomiozea, Globorotalia lenguaensis, Globorotalia plesiotumida)
• Fossils (Diatoms): Actinocyclus ellipticus, Actinoptychus splendens, Actinoptychus undulatus, Cocconeis costata, Cocconeis scutellum, Cocconeis vitrea, Coscinodiscus marginatus, Coscinodiscus cf. nodulifer, Coscinodiscus temperei, Coscinodiscus cf. yabei, Denticulopsis dimorpha, Denticulopsis katayamae, Goniothecium tenue, Grammatophora sp., Paralia sulcata, Rhizosolenia barboi, Rossiella tatsunokuchiensis, Thalassionema nitzschioides
• Tephra: K14

• Kitamura et al. (1986) Geology of the Sendai District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 134p. (in Japanese with English abstract 9p.)
• Kitamura et al. (1983) Geology of the Yoshioka District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 50p. (in Japanese with English abstract 5p.)