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Nantaisan Volcanic Breccia

• Type locality: Mount Nantai, Ibaraki prefecture
• Volcanic rocks
• Higashidaigo basin, Nishidaigo basin
• Miocene (12.5, 12.7 Ma, K-Ar)

• Sedimentary facies: Marine
• Lithofacies: Submarine volcanoe products
• Lithofacies: Tholeiitic andesite, Icelandite
• Lithofacies (Main): In situ hyaloclastite, Reworked hyaloclastite, Pseudo-pillow lava, Lapilli tuff, Tuff breccia, Lava
• Lithofacies (Minor): Interbedded sandstone and mudstone

• Thickness: 50 - 1,000 m
• Upper limit: Conformity, partly Interfingered (Nawashiroda Formation), Interfingered (Nishizome Formation)
• Lower limit: Conformity (Asakawa Formation)

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

• Distribution: Machitsuki - Onamase - Namasefuji - Saigane - Kitatomida - Mount Tsukiore, Daigo city, Kuji county, Ibaraki pref.; Fukuroda fall - Takyu mountain pass, Daigo city, Kuji county, Ibaraki pref.
• Fossils (Gastropods): Phanerolepida expansilabru

• Hosoi et al. (2017) Jour. Geol. Soc. Japan, vol.123, no.8, pp.613-626 DOI
• Amano et al. (2011) Jour. Geol. Soc. Japan, vol.117, Supplement, pp.69-87 DOI
• Tagiri et al. (2008) Jour. Geol. Soc. Japan, vol.114, no.6, pp.300-313 DOI