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Nizaka Tuff Ishida, 1978 ex Kitamura et al., 1981

Invalid synonym: Naruko-Nizaka Tephra

• Type locality: Nizakamukai, Iwadeyama, Osaki city, Miyagi prefecture
• Tephra
• Pleistocene (ca. 80 - 60 ka; 70 - 50 ka, FT, TL)

• Lithofacies (Upper): Volcanic ash
• Lithofacies: Dacite pyroclastic flow deposit (Some flow units)
• Lithofacies: Pumice tuff
• Lithofacies (Bottom): Interbedded pumice and volcanic ash fall deposits, Conglomerate

• Source: Naruko volcano
• Eruptive volume: ca. 5 - 10 km³
• Distribution: ca. 75 km²
• Thickness: 50 m or thicker
• Thickness (Pyroclastic flow deposit): ca. 5 m
• Thickness (Pyroclastic fall deposit): ca. 30 cm - 1 m or thicker
• Volume: 2.2 km³
• Upper limit: Unconformity (Yanagisawa Tuff)
• Lower limit: Unconformity (Iketsuki Tuff, Shimoyamasato Tuff, Onoda Formation, Takashimizu Formation)

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

• Distribution: Nizakamukai - Kamiichikuri - Rokkaku stock farm - Kaminome, Iwadeyama, Osaki city, Miyagi pref.; Takashimizu, Kurihara city, Miyagi pref.

• Tsuchiya et al. (1997) Geology of the Iwagasaki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 96p. (in Japanese with English abstract 4p.)
• Kitamura et al. (1981) Geology of the Furukawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 32p. (in Japanese with English abstract 4p.)