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Kobana Formation

• Coherent formation
• Miocene (? - 12.0 Ma, Ar-Ar)
• Correlation (Lower): Oya Formation, Ozo Formation

• Sedimentary facies: Marine
• Lithofacies (Upper, Main): Muddy sandstone
• Lithofacies (Upper, Minor): Tuff, Pumice tuff
• Lithofacies (Middle, Main): Calcareous sandstone, Muddy sandstone
• Lithofacies (Middle, Minor): Pumice tuff
• Lithofacies (Lower, Main): Gravel-bearing sandstone, Calcareous sandstone
• Lithofacies (Lower, Minor): Muddy sandstone, Sandy mudstone
• Lithofacies (Bottom): Conglomerate

• Upper limit: Conformity (Ogane Formation)
• Lower limit: Unconformity (Motegi Formation)

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

• Distribution: Motegi city, Haga county, Tochigi pref.
• Fossils: Brachiopods
• Fossils (Middle - Upper, Shiobara fauna, Yama fauna): Cyclocardia siogamensis, Thracia sp., Neptunea hukusimensis
• Fossils (Lower, Kadonosawa fauna): Nipponopecten akihoensis, Chlamys cf. arakawai

• Matsui et al. (2011) Jour. Geol. Soc. Japan, vol.117, Supplement, pp.89-102 DOI
• Tagiri et al. (2008) Jour. Geol. Soc. Japan, vol.114, no.6, pp.300-313 DOI
• Hayashi et al. (2008) Jour. Geol. Soc. Japan, vol.114, no.3, pp.141-144 DOI