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Sasaoka Formation (Omura, 1928) Huzioka et al., 1969

• Type locality: Sasaoka, Akita city, Akita prefecture
• Coherent formation
• late Pliocene - Pleistocene (Diatoms, Foraminifera, Haptophytes)
• Correlation: Kannonji Formation

• Sedimentary facies: Shallow marine
• Sedimentary facies: Inner bay
• Water temperature: Cold ocean current
• Depth of water: Upper - lower sublittoral zone
• Lithofacies: Sandstone, Silty sandstone
• Lithofacies (Minor): Conglomerate, Acidic tuff, Sandy tuff
• Sedimentary structures: Trough cross stratification, Swash cross stratification, Channel structure, Convolute lamination

• Thickness: 25 - 740 m
• Upper limit (Nakazawa Formation): Bottom of the soft sandstone bed overlying hard sandstone
• Upper limit: Conformity (Nakazawa Formation), Unconformity (High I Terrace Deposit, Katanishi Formation, Shibikawa Formation, Takaoka Formation, Nishime Formation, Chokai volcanic products, Yurihara Debris Avalanche Deposits, Shirayukigawa Debris Avalanche Deposits)
• Lower limit: Bottom of sandstone dominant bed
• Lower limit: Conformity, partly unconformity (Tentokuji Formation), Unconformity (Subari Andesite, Funakawa Formation, Older Sand Dune Deposits)

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

• Distribution: Sasaoka, Akita city, Akita pref.; Wada, Kawabe, Akita city, Akita pref.; Osugo creek, Inai, Ikawa city, Minamiakita county, Akita pref.; Hanawakawa, Minehama, Noshiro city, Akita pref.; Towari - Yamaya, Noshiro city, Akita pref.; Kogurosawa, Taihei-Teraniwa - Hirasawa, Taihei-Kurosawa, Akita city, Akita pref.; Dewa hills, Akita pref.; Bakkodai, Futatsui town, Noshiro city Akita pref.; Nakazawa, Noshiro city, Akita pref.; Usuizawa river, Fujisato city, Yamamoto county, Akita pref.; Nakakumazawa, Mitane city, Yamamoto county, Akita pref.; Tomita - Terasawa - Yomogidainai, Gojome city, Minamiakita county, Akita pref.; Shimoshinjo - Kitate - Saraminai - Kainosawa, Akita city, Akita pref.; Soba - Okuide - Jinnai, Kawabe, Akita city, Akita pref.; Nakayodo river - Mount Minenoyama, Kyowa, Daisen city, Akita pref.; Futagozawa, Yuwa, Akita city, Akita pref.; Tsuchiya - Tatemae - Manganji - Yakushido - Kuzunori, Yurihonjo city, Akita pref.; Shirahama - Kotoura - Oguni, Nikaho city, Akita pref.; Deto, Nishime town, Yurihonjo city, Akita pref.; Ayu river - Otani pond, Yurihonjo city, Akita pref.; Arasawa, Yashima town, Yurihonjo city, Akita pref.; Nishime river, Nishime town, Yurihonjo city, Akita pref.; Zenjin pond, Yurihonjo city, Akita pref.; Shirayuki river - Torigoe river - Naso river, Nikaho city, Akita pref.
• Fossils: Echinoides (Linthia nipponica), Pollen (Abies sp., Cryptomeria sp., Picea sp., Tsuga sp.), Pipe rocks
• Fossils (Omma-Manganji fauna): Acila gottschei, Acila insignis, Acila nakazimai, Acmaea pallida, Adamnestia japonica, Anadara akitaensis, Anadara amicula, Anadara ommaensis, Anadara satowi, Anadara cf. subcrenata, Angulus vestalcoides, Anisocorbula venusta, Antisabia foliacea, Anomia chinensis, Antiplanes contoraria, Antisabia fuliecea, Arca boucardi, Astarte alaskensis, Astarte borealis, Bittium yokoyamai, Boreoscala yabei echigonum, Brachidontes senhousia, Calliostoma consorsa, Callithaca adamsi, Cancellaria sp., Cardita leana, Ceratostoma modestum, Chlamys cosibensis, Chlamys ferrei, Chlamys jousseaumei, Chlamys nipponensis, Chlamys satoi, Chlamys swiftii, Clavus braunsi, Clinocardium bulowi, Clinocardium californiense, Clinocardium ciliatum, Clinocardium fastosum, Clinocardium nutallii, Collisella heroldi, Conchocele bisecta, Conchocele nipponica, Cryptonatica janthostomoides, Cryptonatica tugaruana, Cuspidaria ligula, Cuspidaria gouldiana septentrionalis, Cyclocardia ferruginea, Cyclocardium biilowi, Cyclocardium ciliatumDentalium octangulatum, Dentalium vernedei, Dentalium weineauffi, Dosinia japonica, Ennucula nipponica, Etremopa subauriformis, Eocylichna braunsi, Eufenella rufocinata, Euspira pila, Ezocallista brevishonata, Fabulina iridella, Felaniella usta, Fulgoraria sp., Fulvia mutica, Fusitriton oregonensis, Glycymeris minochiensis, Glycymeris nipponica, Glycymeris pilsbryi, Glycymeris vestita, Glycymeris yessoensis, Heteromacoma irus, Heteromacoma yantaiensis, Homalopoma sangarense, Leucotina gigantea, Lima hakodatensis, Limatula kurodai, Limopsis crenata, Limopsis cumingii, Limopsis tokaiensis, Liocyma sp., Lucinoma acutilineata, Lucinoma annulata, Lucinoma otukai, Lucinoma spectabilis, Lunatia pila, Lunatia pila ovata, Macoma calcarea, Macoma incongrua, Macoma nipponica, Macoma praetexta, Macoma tokyoensis, Mammila kurodai, Mercenaria chitaniana, Mercenaria yokoyamai, Mesalia akitana, Mizuhopecten kurosawaensis, Mizuhopecten poculum, Mizuhopecten tokyoensis hokurikuensis, Mizuhopecten yessoensis, Modiolatus nitidus, Modiolus difficilis, Modiolus nipponica, Mohnia yanamii, Monia macrochisma, Monia umbonatus, Mya cuneiformis, Myadora japonica, Myadora reeveana, Mya japonica, Mytilus grayanus, Nassarius caelatus, Nemocardium samarangae, Neverita didyma, Nuculana pernula sadoensis, Nuculana yokoyamai, Ocenebra adunca, Ophiodermella miyatensis, Ophiodermella pseudopannus, Pandora pulchella, Panope japonica, Paphia euglipta, Patinopecten kurosawaensis, Pectunculina oblonga, Peronidia venulosa, Phillucina yamakawai, Polynemamussium intuscostatum, Porterius dalli, Propebela candita, Protothaca adamsi, Puncturella fastigiata, Puncturella nobilis, Ranella cf. galea, Relicunassa festiva, Saccella confusa, Sealesia fuscolabiata, Serripes groenlandica, Sinum sp., Siphonalia cf. fusoides, Solamen diaphana, Solemya japonica, Soletellina diphos, Spisula sachalinensis, Spisula voyi, Suavodrillia declivis, Swiftopecten swiftii, Tachyrhyncus venustellus, Tectonatica janthostoma, Tectonatica tugaruana, Trapezium japonicum, Trophonopsis beringi, Trophonopsis uyemurai, Trophopsis sp., Tugurium exutum, Turritella cf. otukai, Turritella saishuensis, Turritella saishuensis motidukii, Umbonium akitanum, Umbonium giganteum, Venericardia ferruginea, Venericardia prolongate nakamurai, Vermetus ebaranus, Yabepecten tokunagai, Yoldia amygdalea, Yoldia notabilis
• Fossils (Calcareous nannofossils): Reticulofenestra spp., Coccolithus pelagicus, Braarudosphaera bigelowii, Helicosphaera sellii, Calcidiscus leptoporus, Helicosphaera carteri
• Fossils (Foraminifera): Ammonia ketienziensis angulata, Angulogerina angulosa, Angulogerina kokozuraensis, Astrononion umbilicatulum, Buccella frigidus, Buccella inusitata, Buccella nipponica, Bulimina aculeata, Bulimina marginata, Bulimina nipponica, Buliminella elegantissima, Bolivina decussata, Bolivina robusta, Bolivinita quadrilatera, Buccella frigidus, Buccella inusitata, Bulimina aculeata, Bulimina elegantissima , Bulimina exilis, Bulimina exilis tenuata, Bulimina marginata, Bulimina nipponica, Bulimina tenuata, Cassidulina cf. depressa, Cassidulina japonica, Cassidulina kasiwazakiensis, Cassidulina cf. margareta, Cassidulina norcrossi, Cassidulina orientale, Cassidulina subglobosa, Cassidulina sublimbata, Cassidulina yabei, Cassidulinoides compacta, Cibicides aknerianus, Cibicides lobatulus, Cibicides pseudoungerianus, Cibicides cf. reflugens, Cibicides ungerianus, Cribroelphidium bartletti, Cribrononion clavatum, Dentalina setanaensis, Dentalina siribesiensis, Discopulvinulina bradyi, Discopulvinulina orbicularis, Discorbis sp., Elphidium advenum, Elphidium clavatum, Elphidium crispum, Elphidium etigoense, Elphidium fax barbarense, Elphidium clavatum, Elphidium hanzawai, Elphidium hughesi, Elphidium hughesi foraminosum, Elphidium jenseni, Elphidium subarctium, Elphidium subgranulosum, Epistominella naraensis, Epistominella nipponica, Epistominella pulchella, Eponides nipponica, Eponides umbonatus, Fissulina laucunata, Fissulina spp., Fursenkoina mexicana, Gaudryina sp., Glabratella spp., Globigerina bulloides, Globigerina foliata, Globigerina pachyderma, Globigerina quinquelaba, Globigerina suber, Globobulimina auriculata, Globocassidulina subglobosa, Globorotalia inflata, Globorotalia obesa, Guttulina yamazakii, Hanzawaia nipponica, Heronallenia spp., Islandiella japonica, Karreriella baccata japonica, Lagena acticosta, Lagena laevis, Lagena sulcata, Lagenonodosaria scalaris, Laryngosima sp., Lenticulina spp., Loxostomoides bradyi, Miliolinella sp., Nonion aimonoi, Nonion grateloupi, Nonion japonicum, Nonion labrodoricum, Nonion manpukuziense, Oolina hexagona, Oridorsalis umbonatus, Parafissurina sp., Planulina wuellerstorfi, Pseudononion grateloupi, Pseudononion japonicum, Pseudononion tredecum, Pseudorotalia gaimardii, Pullenia apertula, Pullenia quinqueloba, Pullenia salisburyi, Quinqueloculina seminulum, Rectobolivina raphana, Rosalina bradyi, Rotalia beccari, Rotalia japonica, Siphogenerina raphana, Siphotextularia saulcyana, Spiroloculina communis, Trifalina kokozuraensis, Uvigerina akitaensis, Uvigerina asanoi, Uvigerina yabei, Valvulineria sadonica
• Fossils (Diatoms): Actinocyclus ehrebergii, Actinocyclus ingens, Actinoptychus undulatus, Chaetoceros sp., Cocconeis costata, Cocconeis scutellum, Coscinodiscus marginatus, Cyclotella comta, Denticulopsis seminae, Denticulopsis kamtschatica, Grammatophora sp., Melosira granulata, Melosira italica, Melosira sulcata, Rhaphoneis amphiceros, Rhaphoneis angustata, Rhaphoneis surirella, Stephanopyxis turris, Thalassionema nitzschioides, Thalassionema nitzschioides var. parva, Thalassionema hirosakiensis, Thalassiosira antiqua, Thalassiosira excentica, Thalassiosira praeconvexa, Thalassiosira zabelinae
• Fossils (Haptophytes): Gephyrocapsa caribbeanica, Gephyrocapsa oceanica

• Sato et al. (2012) Jour. Geol. Soc. Japan, vol.118, no.2, pp.62-73 DOI
• Amano et al. (2011) Jour. Geol. Soc. Japan, vol.117, no.9, pp.508-522 DOI
• Nishikawa et al. (2008) Jour. Geol. Soc. Japan, vol.114, Supplement, pp.75-85 DOI
• Murakami et al. (2008) Jour. Geol. Soc. Japan, vol.114, Supplement, pp.111-120 DOI
• 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.)
• Nakano and Tsuchiya (1992) Geology of the Chokaisan and Fukura District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 138p. (in Japanese with English abstract 7p.)
• Ozawa et al. (1988) Geology of the Yashima District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 87p. (in Japanese with English abstract 5p.)
• 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.)
• Ozawa et al. (1985) Geology of the Moritake District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 69p. (in Japanese with English abstract 5p.)
• Ozawa et al. (1984) Geology of the Noshiro District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 91p. (in Japanese with English abstract 9p.)
• Ozawa et al. (1982) Geology of the Kisakata District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 73p. (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 et al. (1977) Geology of the Honjo District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 54p. (in Japanese with English abstract 4p.)
• Huzioka et al. (1976) Geology of the Ugo-Wada District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 65p. (in Japanese with English abstract 5p.)
• Hase and Hirayama (1970) Geology of the Gojome District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 46p. (in Japanese with English abstract 6p.)