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Minamiimogawa Formation (Tsuda et al., 1984) Kudo et al., 2011

Invalid synonym: Kubiki Formation, Deto Formation

• Type locality: Ikarashi river, Minamiomogawa, Shimoda, Sanjo city, Niigata prefecture
• Coherent formation
• middle - late Miocene (ca. 12.3 - 7.2 Ma, Diatoms)

• Sedimentary facies: Marine
• Depth of water: Bathyal
• Lithofacies: Mudstone, Diatomaceous mudstone, Biotite/Hornblende-deficient Rhyolite pumice lapilli tuff, Tuff
• Lithofacies (Minor): Glauconite sandstone

• Thickness: 0 - ca. 900 m
• Upper limit: Unconformity (Kakuma Formation, Minagawa Formation, Lower II Terrace Deposit)
• Lower limit: Conformity (Nanatani Formation)

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

• Distribution: Ikarashi river - Komade river, Kitaimogawa, Shitada, Sanjo city, Niigata pref.; Nigorisawa, Sanjo city, Niigata pref.; Nanatani, Kamo city, Niigata pref.; Araya, Gosen city, Niigata pref.; Futsuka town, Nagaoka city, Niigata pref.
• Fossils: Dinoflagellates
• Fossils (Radiolarians): Cromyodruppa concentrica, Spongodiscus spp.
• Fossils (Diatoms): Actinoptychus senarius, Aulacoseira spp., Cavitatus spp., Coscinodiscus marginatus, Denticulopsis dimorpha var. dimorpha, Denticulopsis praedimorpha var. minor, Denticulopsis praedimorpha var. praedimorpha, Denticulopsis simonsenii, Denticulopsis vulgaris, Goniothecium odontella, Nitzschia pliocena, Paralia sulcata, Thalassionema schraderi, Thalassiosira antiqua, Thalassiosira temperei
• Tephra: Kmgg, Dtbt

• Kudo et al. (2011) Geology of the Kamo District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 162p. (in Japanese with English abstract 4p.)
• Kudo et al. (2011) Jour. Geol. Soc. Japan, vol.117, no.5, pp.277-288 DOI
• Hiranaka et al. (2009) Jour. Geol. Soc. Japan, vol.115, no.4, pp.177-186 DOI