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Hakobuchi Formation (Matsumoto, 1942) Takashima et al., 2001

Invalid synonym: Hakobuchi Group, Ul (Upper Yezo Group), Pankezawa Formation (Local name at Chikubetsu area)

• Type locality: Oyubari dam, Oyubari, Yubari city, Hokkaido
• Coherent formation
• Late Cretaceous, Campanian - Paleocene

• Sedimentary facies: Shallow marine, Fluvial
• Sedimentary facies: Incised valley, Inner shelf, Lower shoreface
• Sedimentary facies: Meandering river, Transgressive lag deposit
• Depth of water: Outer shelf, Tidal zone
• Lithofacies: Sandstone, Conglomerate
• Lithofacies (Minor): Sandy siltstone, Coal, Mudstone
• Sedimentary structures: Hummocky cross-stratification, Trough cross-stratification

• Thickness: ca. 1,500 m
• Upper limit: Angular unconformity (Haboro Formation, Noborikawa Formation, Poronai Group)
• Lower limit: Transitional (Haborogawa Formation, The boundary between the sandy musdstone bed of Unit 3 of Kashima Formation and the overlying medium sandstone bed of Hakobuchi Formation)
• Lower limit: Unconformity (Kashima Formation, Haborogawa Formation (Pankezawa Formation in Chikubetsu area))

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

• Distribution: Soya-Nakatonbetsu, Saku-Abirashinai, Ashibetsu - Oyubari - Hobetsu, Chikubetsu, Kotanbetsu, Teshio-Nakagawa, Tomamae, Mikasa, Hokkaido
• Distribution: Mayachi creek, Mayachi - Oyubari dam, Yubari city, Hokkaido; Horokakuruki river, Noborikawa, Yubari city, Hokkaido; Porosaru creek - Tosano creek, Mukawa city, Yufutsu county, Hokkaido
• Distribution: Kotanbetsu river, Onko creek, Nakanosawa creek, Uenosawa creek, Hotate creek, Yaguchi creek, Omagari creek, Kotanbetsu, Tomamae city, Tomamae county, Hokkaido
• Fossils: Foraminifera, Tree trunks, Trace (Thalassinoides isp., Ophiomorpha isp.)
• Fossils (Ammonoids): Damesites sugata, Gaudryceras tenuiliratum, Anagaudryceras yokoyamai
• Fossils (Ammonoids, Pankezawa Formation in Chikubetsu): Canadoceras multicostatum, Schlueterella kawadai, Anapachydiscus fascicostatus
• Fossils (Bivalves): Sphenoceramus naumanni, Sphenoceramus cf. cristatus, Inoceramus (Platyceramus) sp., Nucula sp., Heterotrigonia sp., Periplomya nagaoi
• Key bed: Sanushube Sandstone (Green sandstone)

• Takashima et al. (2018) Jour. Geol. Soc. Japan, vol.124, no.6, pp.381-398 DOI
• Shimada et al. (2013) Jour. Geol. Soc. Japan, vol.119, no.6, pp.432-436 DOI
• Hayashi et al. (2011) Jour. Geol. Soc. Japan, vol.117, no.1, pp.14-34 DOI
• Tsujino (2009) Jour. Geol. Soc. Japan, vol.115, no.3, pp.122-129 DOI
• Hoyanagi et al. (2007) Jour. Geol. Soc. Japan, vol.113, Supplement, pp.205-215 DOI
• Ando et al. (2007) Jour. Geol. Soc. Japan, vol.113, Supplement, pp.185-203 DOI