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Hakoi Formation Shiraishi, 1988

Invalid synonym: Hakoi Terrace Deposit

• Type locality: Hakoi terrace, Iriai, Oga city, Akita prefecture
• Coherent formation
• Pleistocene (Last glacial period)

• Sedimentary facies: Lacustrine
• Sedimentary facies (Tarusawa): Lahar deposit
• Climate: Cold (Pollen)
• Lithofacies (Upper): Clayey sand, Sand
• Lithofacies (Lower): Mud, Peat, Gravels

• Thickness: 5.5 m or thinner
• Upper limit: Interfingered (Urata Lava, Iwashimizu Lava)
• Lower limit: Unconformity (Katanishi Formation, Tominaga Lava)

• Distribution: Hakoi terrace, Iriai, Oga city, Akita pref.; Tarusawa, Wakimoto, Oga city, Akita pref.
• Fossils (Pollen): Abies sp., Picea sp., Tsuga sp.
• Tephra: AT, Tarusawa Tephra

• 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