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Sk Tephra

Abbr.: Sk

• Tephra
• Pliocene - Pleistocene (2.3 Ma, FT)

• Lithofacies: Biotite-bearing pumiceous - vitreous volcanic ash

• Host: Ogawa Formation
• Thickness: ca. 20 m

• Distribution: Nagasawa river, Sekiya, Iiyama city, Nagano pref.

• Yanagisawa et al. (2000) Geology of the Iiyama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 144p. (in Japanese with English abstract 6p.)