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Monzen Formation Fujioka, 1954

Invalid synonym: Nishioga Formation, Nishioga Group, Tatejima Conglomerate Member (Daijima area)

• Type locality: Nishikurosawa - Hatake, Kitaura, Oga city, Akita prefecture
• Alkaline - alkali-rich calc-alkaline submarine volcano complexes, Scoria cone
• Volcanic rocks
• late Eocene (37 - 27 Ma, FT; 37 - 27 Ma, K-Ar)
• Correlation: Fujikuragawa Formation, Haginari-Okuramatasawa Formation, Oyana Formation, Yamauchi Formation, Yunosawagawa Formation
• Intruded by: Olivine augite dolerite

• Sedimentary facies: Marine
• Sedimentary facies (Upper): Sub-marine block lava
• Sedimentary facies: Pillow lava, Hyaloclastite, Block and ash flow deposit, Pyroclastic flow deposit
• Depth of water: Shallow (Trace fossils)
• Lithofacies (Upper): Biotite-bearing rhyolite lava
• Lithofacies (Upper, Basal): Tuffaceous conglomerate, Sandstone, Lapilli tuff
• Lithofacies: Alkaline olivine basalt - Basaltic trachyandesite, Basalt - Basaltic andesite aa lava, Pyroclastic flow deposit, Trachyte - Dacite block lava, Dacite volcanic breccia - tuff breccia, Dacite lapilli tuff, Tuff, Andesite sub-marine block lava
• Lithofacies (Minor): Tuffaceous conglomerate, Tuffaceous sandstone, Siltstone

• Thickness: 700 m or thicker
• Upper: Unconformity (Nishikurosawa Formation, Daijima Formation, Nomuragawa Formation, Onnagawa Formation), Abut unconformity (Tateyamazaki Dacite)

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

• Distribution: Cape Shiose, Kohama, Funagawaminato, Oga city, Akita pref.; Monzen, Honzan, Funagawaminato - Akashima, Toga, Oga city, Akita pref; Cape Daimyojin, Nishikurosawa, Kitaura, Oga city, Akita pref.; Ogayama pasture, Kitaura, Oga city, Akita pref.

• Kano (2018) Jour. Geol. Soc. Japan, vol.124, no.10, pp.781-803 DOI
• Kano et al. (2012) Jour. Geol. Soc. Japan, vol.118, no.6, pp.351-364 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.)
• Kobayashi et al. (2010) Jour. Geol. Soc. Japan, vol.116, no.10, pp.552-562 DOI
• Sato et al. (2009) Jour. Geol. Soc. Japan, vol.115, no.1, pp.31-46 DOI
• Ohguchi et al. (2008) Jour. Geol. Soc. Japan, vol.114, Supplement, pp.17-32 DOI
• Fujimoto et al. (2008) Jour. Geol. Soc. Japan, vol.114, Supplement, pp.51-74 DOI
• Ozawa et al. (1985) Geology of the Ugo-Hamada District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 57p. (in Japanese with English abstract 4p.)