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Yabuta Formation

Synonym: Yabuta Siltstone Member

• Coherent formation
• Pliocene
• Correlation: Sakiyama Siltstone Member, Zukawa Sandstone Member, Futakami Siltstone Member

• Lithofacies (Upper): Calcareous sandstone
• Lithofacies: Sandy siltstone
• Lithofacies (Middle, Minor): Calcareous sandstone
• Lithofacies (Lower, Minor): Pumice tuff
• Lithofacies (Basal): Glauconite sandstone
• Sedimentary structures (Upper): Cross stratification

• Thickness: ca. 120 - 200 m
• Upper limit: Conformity (Murakami Siltstone Member)

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

• Distribution: Ozakai - Ao - Asahiyama - Abugashima island, Himi city, Toyama pref.
• Fossils: Sponges (Spicules), Foraminifera, Radiolarians, Diatoms
• Fossils (Shellfishes): Acila insignis, Chlamys swifti, Conchocele nipponica, Glycymeris pilsbry, Glycymeris yessoensis, Lucina acutilineata, Lucinoma sp., Mactra sp., Natica sp., Nuculana sp., Pecten kurosawaensis, Pecten tokyoensis, Pecten yessoensis, Turritella saishuensis, Turritella saishuensis etigoensis, Umbonium sp., Venericardia ferruginea

• Amano et al. (2012) Jour. Geol. Soc. Japan, vol.118, no.12, pp.810-822 DOI
• Imai et al. (1966) Geology of the Ochigata and Abugashima District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 67p. (in Japanese with English abstract 4p.)