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Anno Formation Wakimizu, 1933

Invalid synonym: Hagyu Formation, Hagyu Pyroclastic Rock Formation

• Type locality: Kurotaki fall, Godaihata, Kimitsu city, Chiba prefecture
• Coherent formation
• Forearc basin sediments
• Pliocene (Foraminifera)
• Correlation: Ikego Formation, Kagamigaura Formation, Hedate Formation, Shirahama Formation, Shiramazu Formation, Anno Formation

• Sedimentary facies: Marine
• Depth of water: Lower middle bathyal (Benthonic foraminifera)
• Lithofacies (Upper): Mudstone, Sandy mudstone
• Lithofacies (Lower): Mudstone-dominant interbedded sandstone and mudstone
• Lithofacies (Lower, Minor): Turbidite
• Lithofacies (Minor): Tuff, Scoria, Tuffaceous sandstone
• Sedimentary structures: Slump structures

• Thickness: 125 - 386 m
• Upper limit: Kurotaki Unconformity (Kurotaki Formation)
• Lower limit: Bottom of An1
• Lower limit: Conformity (Kiyosumi Formation)

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

• Distribution: Shikoma river, Shikoma, Futtsu city, Chiba pref.; Aikawa - Takeoka, Futtsu city, Chiba pref., Minato river, Seki, Futtsu city, Chiba pref., Kurotaki fall - Anno, Godaihata, Kimitsu city, Chiba pref.; Koito river - Katakura, Toyofusa, Kimitsu city, Chiba pref.; Oppara - Konita - Saagawa - Hosono - Obitsugawa river, Kimitsu city, Chiba pref.; Mikuta creek, Kawamata, Kimitsu city, Chiba pref.; Cape Myogane, Kyonan city, Awa county, Chiba pref.; Sasa - Kanayama dam, Kamogawa city, Chiba pref.; Omori - Nakasato, Katsuura city, Chiba pref.
• Fossils: Fossils
• Fossils (Calcareous nannofossils): Calcidiscus sp., Coccolithus sp., Ceratolithus sp., Discoaster sp. Florisphaera sp., Gephyrocapsa sp., Helicosphaera sp., Pseudoemiliania sp., Reticulofenestra sp., Rhabdosphaera sp., Sphenolithus sp., Syracosphaera sp., Umbilicosphaera sp.
• Tephra: An1, An2, An20, An21, An49, An73, An107, An108, An116, An117, An156, An157, An158

• Yamamoto et al. (2016) Jour. Geol. Soc. Japan, vol.123, no.1, pp.41-55, DOI
• Takahashi et al. (2016) Jour. Geol. Soc. Japan, vol.122, no.8, pp.375-395, DOI
• Kokado et al. (2015) Jour. Geol. Soc. Japan, vol.121, no.10, pp.359-372, DOI
• Kameo and Sekine (2013) Jour. Geol. Soc. Japan, vol.119, no.6, pp.410-420 DOI
• Sawada et al. (2009) Jour. Geol. Soc. Japan, vol.115, no.5, pp.206-222 DOI
• Nakajima and Watanabe (2005) Geology of the Futtsu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 102p. (in Japanese with English abstract 8p.)
• Suzuki et al. (1990) Geology of the Nago District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 48p. (in Japanese with English abstract 3p.)
• Nakajima et al. (1981) Geology of the Kamogawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 107p. (in Japanese with English abstract 7p.)