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Kitanomatasawa Formation Kano et al., 2012

Invalid synonym: Okuramata Formation, Sunakobuchi Formation, Tsuyukuma Formation, Yashiki Mudstone, upper Aniai Formation, Kitanomata Dacite Member

• Type locality (Volcanic rocks): Kitanomata creek - Okuramata creek, Gojome city, Minamiakita county, Akita prefecture
• Type locality (Sub, Sedimentary rocks): Horinai creek, Kamikoani city, Kitaakita county, Akita prefecture
• Coherent formation
• middle Miocene (16.5 - 12.3 Ma, Microfossils, 17.4 - 12.8 Ma, K-Ar)
• Correlation: Katsurabuchi Formation, Shiotezawa Formation
• Intruded by: Houzukiyama Dacite, Babame Dolerite, Nibetsu Granite, Tsukushimori Rhyolite, Granodiorite porphyry, Dolerite

• Sedimentary facies: Shallow marine
• Sedimentary facies: Submarine volcanoes
• Sedimentary facies (Upper): Lava dome
• Depth of water: 150 m or shallower (Shellfishes)
• Depth of water: Bathyal (Foraminifera)
• Lithofacies (Upper): Mudstone, Siltstone, Sandstone, Dacite- rhyolite lava, Tuff breccia, Lapilli tuff, Pumice tuff (Pyroclastic flow deposit)
• Lithofacies (Lower): Conglomerate, Sandstone, Basalt lava (Hyaloclastite, Pillow lava), Agglomerate, Volcanic breccia, Tuff breccia, Lapilli tuff, Tuff
• Lithofacies (Lower, Minor): Mudstone

• Thickness: 60 - 1,200 m
• Upper limit: Transitional (Onnagawa Formation), Unconformity (Himegatake Andesite, Kurasawayama Welded Tuff)
• Lower limit: Transitional (Utto Formation), Unconformity (Yamayakawa Formation)

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

• Distribution: Kitanomata creek - Okuramata creek - Animata creek - Usunai creek - Oboro creek, Gojome city, Minamiakita county, Akita pref.; Horinai creek - Koani river, Kamikoani city, Kitaakita county, Akita pref.; Nagataki creek - Ani river - Tsuyukuma creek, Ani town, Kitaakita city, Akita pref.; Sunagobuchi, Sannai, Kawabe, Akita city, Akita pref.; Omata river - Sunakobuchi, Kawabe, Akita city, Akita pref.; Arakawa river - Okuyama river, Kyowa, Daisen city, Akita pref.; Nishinagano, Kakunodate, Senboku city, Akita pref.
• Fossils: Sharks (Teeth), Crabs, Shrimps, Echinoids (Needles), Fish scales, Brachiopods, Foraminifera, Calcareous nannofossils (Sphenolithus heteromorphus), Radiolarians (Calcycletta costata)
• Fossils (Shellfishes): Acila (Truncacila) sp., Anadara makiyamai, Anisocorbula ohiroi, Anisocorbula peregrina, Cardita siogamensis, Cerithidea sp., Chlamys akitana, Chlamys cosibensis hanzawae, Chlamys kaneharai, Chlamys cf. minoensis, Clementia? sp., Crassatelites suyamensis, Crassostrea gravitesta, Cryptopecten cf. yanagawaensis, Ctena hataii, Cultellus izumoensis, Dentalium katayamai, Dentalium yokoyamai, Dosinia kaneharai, Dosinia nomurai, Fablina sp., Fulgoraria striata, Glycymeris sp., Halicardia akitaensis, Hiatella sp., Lima sp., Macoma calcarea, Masudapecten iwasakiensis, Mizuhopecten kimurai, Mizuhopecten kimurai murayamai, Mytilus sp., Nanochlamys cf. notoensis, Nassarius? sp., Natica sp., Nuculana cf. confusa, Ostrea sp., Pallicrum peckhami, Paphia suzuensis, Placopecten protomollitus, Saccella cf. confusa, Saxolucina khatai, Serripes? sp., Shichiheia cf. etchuensis, Tellina sp., Umbonium sp., Vasticardium cf. ogurai, Venericardia siogamensis, Xenophora sp.
• Fossils (Daijima-type flora): Cinnamomum miocenum
• Fossils (Foraminifera): Alabamina japonica, Ammobaculites incertus, Ammodiscoides turbinatus, Ammodiscus sp., Ammonia hatatatensis, Amphicoryna sp., Amphistegina lessorii, Angulogerina kokozuraensis, Anomalina globrata, Astrononion sp., Bathysiphon arenaceae, Bolivina cf. marginata masudai, Bucella tanai, Bulimina sp., Cancris auriculus, Cassidulina cf. laerigata, Cassidulina cf. margareta, Cassidulina subglobosa, Cibicides malloryi, Cribrostomoides cf. subglobosum, Cribrostomoides evoluta, Cribrostomoides cancellata, Cribrostroides sp., , Cyclammina japonica, Cyclammina pusilla, Dentalina insecta, Dorothia aubrotundata, Ehrenbergina sp., Elphidium sp., Eponides unbonatus, Fissurina sp., Frondicularia sp., Frusenkoina cf. akitaensis, Globigerina praebulloides, Globigerina woodi, Globigerinita glitinata, Globigerinoides trilobus, Globobulimina auriculata, Globocassidulina globosa, Globoquadrina venezuelana, Globoquadrina altispira altispira, Globorotalia birnageae, Globorotalia cf. fohsi, Globorotalia menardii praemenardii, Globorotalia cf. miozea, Globorotalia peripheroronda, globorotalia quinifalcata, Grabratella sp., Guttlina sp., Gyroidina orbicularis, Hanzawaia tagaensis, Haplophragmoides cf. evolutum, Haplophragmoides trullissatum, Hopkinsina morimachiensis, Hopkinsina shinboi, Lagena costata, Lagena sulcata spicata, Lenticulina cf. asanoi, Lenticulina lucida, Martinotiella communis, Melonis nicobarense, Melonis pompilloides, Miogypsina? sp., Nodosaria longiscata, Nodosaria obliquatrosa, Nonionella miocenica, Nonion japonicum, Nonion cf. labradoricum, Oolina sp., Operculina sp., Oridorsalis umbonatus, Pullenia bulloides, Pullenia salishuryi, Quadrimorphina sp., Reussella sp., Rosalina sp., Sigmoiloposis schlumbergeri, Sphaeroidina bulloides, Sphaeroidina japonica, Spirosigmoilinella compressa, Stilostromella lepicula, Textularina sp., Trochammina cf. nobensis, Uvigerina crassicostata, Uvigerina proboscidea, Virgulinella miocenica

• Kano (2018) Jour. Geol. Soc. Japan, vol.124, no.10, pp.781-803 DOI
• Kano et al. (2012) Geology of the Aniai District, 2nd Edition, 1:50,000 Quadrangle Series, Geological Survey of Japan, AIST, 59p. (in Japanese with English abstract 4p.)
• Tsuchiya and Yoshikawa (1994) Geology of the Kariwano District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 72p. (in Japanese with English abstract 4p.)
• Ozawa et al. (1981) Geology of the Taiheizan District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 69p. (in Japanese with English abstract 4p.)
• Huzioka et al. (1977) Geology of the Akita District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 69p. (in Japanese with English abstract 5p.)
• Ozawa and Sumi (1957) Moriyoshiyama, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 42p. (in Japanese with English abstract 5p.)