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Aoso Formation (Nakamura, 1941) Kitamura et al., 1983

• Type locality: Aoso shrine, Aosozawa, Miyagino ward, Sendai city, Miyagi prefecture
• Coherent formation
• late Miocene
• Correlation: Tsunaki Formation

• Sedimentary facies: Continental shelf (Foraminifera)
• Lithofacies: Sandstone
• Lithofacies (Minor): Pumice tuff, Tuff, Siltstone, Conglomerate
• Sedimentary structures: Planar cross-stratification, Trough cross-stratification, Graded bedding

• Thickness: 20 - 220 m
• Upper limit (Nanakita Formation): Top of K8
• Upper limit: Conformity (Nanakita Formation, Omatsuzawa Formation), Unconformity (Miyatoko Tuff Member)
• Lower limit: Transitional (Bangamoriyama Formation), Conformity (Otsutsumi Formation), Abut unconformity (Matsushimawan Group)

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

• Distribution: Aoso shrine, Aosozawa, Miyagino ward, Sendai city, Miyagi pref.; Irisugaya, Rifu city, Miyagi county, Miyagi pref.; Tomiya, Tomiya city, Miyagi pref.; Numata river - Konishi river, Taiwa city, Kurokawa county, Miyagi pref.; Yamazaki river, Osato city, Kurokawa county, Miyagi pref.; Dodokoro, Izumi ward, Sendai city, Miyagi pref.
• Fossils (Shellfishes): Chlamys miyatokoensis matumori, Clinocardium sp., Crassostrea gigas, Dosinia kaneharai, Glycymeris matumoriensis, Homalopoma sp., Mizuhopecten matumoriensis, Mizuhopecten cf. paraplebejus, Nanaochlamys notoensis otutumiensis, Spisula cf. voyi
• Fossils (Foraminifera): Ammonia cf. beccarii, Amphicoryna fukushimaensis, Astrononion cf. umbilicatulum, Baggina notoensis, Buccella cf. tenerrina, Cibicides lobatulus, Cibicides refulgens, Cibicides tani, Dentalina sp., Elphidiella hannai, Elphidium cf. fimbriatulum, Elphidium jenseni, Elphidium sendaiense, Elphidium cf. subarcticum, Evolvocassidulina sp., Fissurina marginata, Fissurina orbignyana, Gavelinopsis sp., Glabratella sp., Globigerina bulloides, Globigerina falconensis, Globigerina praebulloides, Globigerina woodi, Globigerinoides quadrilobatus immaturus, Globigerinoides quadrilobatus sacculifer, Globigerinoides sacculifer, Globigerinoides triloba, Globocassidulina cf. depressa, Globoquadrina dehiscens, Globorotalia acostaensis, Globorotalia conomiozea, Globorotalia continuosa, Globorotalia cultrata, Globorotalia lenguaensis, Globorotalia menardii, Globorotalia cf. plesiotumida, Globorotalia tumida plesiotumida, Guttulina sanoi, Hanzawaia nipponica, Islandiella cf. japonica, Melonis cf. affinis, Melonis pompilioides, Neogloboquadrina sp., Nonion japonicus, Orbulina suturalis, Orbulina universa, Oridorsalis tener, Paracassidulina nipponensis, Pseudononion cf. japonicum, Pullenia salisburyi, Quinqueloculina sp., Robulus cf. orbicularis, Rosalina australis, Rosalina cf. bradyi, Sigmomorphina sp., Sphaeroidinellopsis subdehiscens, Trifarina hughesi, Trifarina kokozuraensis
• Fossils (Diatoms): Thalassiosira leptopus
• Tephra: K6, K7, K8

• Kitamura et al. (1986) Geology of the Sendai District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 134p. (in Japanese with English abstract 9p.)
• Kitamura et al. (1983) Geology of the Yoshioka District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 50p. (in Japanese with English abstract 5p.)