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Kitaura Formation (Ohashi ex Toyama, 1925) Chitani, 1930

• Type locality: Kitaura seashore - Hamamaguchi, Oga city, Akita prefecture
• Coherent formation
• early Pleistocene, Gelasian (1.8 - 1.6 Ma, Calcareous nannofossils)
• Correlation: Mamurogawa Formation

• Sedimentary facies: Marine
• Sedimentary facies: Submarine fan
• Sedimentary facies (Lower): Turbidite
• Depth of water: Upper bathyal (200 - 1,000 m, Foraminifera)
• Lithofacies (Upper): Interbedded tuffaceous sandstone and mudstone
• Lithofacies (Middle): Siltstone-dominant interbedded tuffaceous sandstone and siltstone
• Lithofacies (Middle, Minor): Sandstone
• Lithofacies (Lower): Interbedded sandstone and siltstone
• Lithofacies (Minor): Tuff
• Sedimentary structures: Parallel stratification, Current ripples
• Paleocurrent: East
• Paleocurrent: South southwest - North northeast, South southeast - North northwest

• Thickness: 900 - 1,250 m
• Upper limit: Boundary between interbedded sandstone and mudstone and overlying massive sandy siltstone
• Upper limit: Conformity (Wakimoto Formation), Unconformity (Hashimoto Formation, Katanishi Formation, Aikawa and Kotokawa Terrace Deposit)
• Lower limit: Bottom of Ak3
• Lower limit: Conformity (Nishimizuguchi Formation), Onlap unconformity (Minamihirasawa Formation)

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

• Distribution: Komasu river, Aikawa, Kitaura - Hamamaguchi, Oga city, Akita pref.; Cape Oibanazaki - Kanegawa, Oga city, Akita pref.; Hamamaguchi, Oga city, Akita pref.
• Fossils: Sponges (Makiyama chitanii), Radiolarians, Diatoms, Pollen (family Taxodiaceae, Fagus sp.)
• Fossils (Bivalves): Chlamys cosibensis, Delectopecten peckhami, Nucula pernula, Nucula sadoensis, Thyasira tokunagai
• Fossils (Calcareous nannofossils): Acanthoica spp., Braarudosphaera bigelowii, Calcidiscus leptoporus, Coccolithus pelagicus, Coccolithus streckerii, Discolithina japonica, Gephyrocapsa caribbeanica, Gephyrocapsa oceanica, Gephyrocapsa spp., Helicosphaera carteri, Helicosphaera sellii, Neogloboquadrina (Globigerina) pachyderma, Reticulofenestra spp.
• Fossils (Foraminifera): Miliammia echigoensis, Neogloboguadorina pachyderma
• Tephra (26 beds): Ak3, Ak1, Km3 (= Omine-SK110), Km2 (= SK100)

• Sato et al. (2012) Jour. Geol. Soc. Japan, vol.118, no.2, pp.62-73 DOI
• Kano et al. (2011) Geology of the Toga and Funakawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 127p. (in Japanese with English abstract 4p.)
• Shiraishi et al. (2008) Jour. Geol. Soc. Japan, vol.114, Supplement, pp.33-50 DOI
• Fujimoto et al. (2008) Jour. Geol. Soc. Japan, vol.114, Supplement, pp.51-74 DOI