[ Top ] [ Japanese ]

NA4 Tephra

Abbr.: NA4

• Type locality: Niigata prefecture
• Tephra
• Pliocene

• Lithofacies: Rhyolite vitreous volcanic ash

• Host: Minagawa Formation

• Distribution: Nobe river, Ojiya city, Niigata pref.

• Yanagisawa et al. (1986) Geology of the Ojiya District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 177p. (in Japanese with English abstract 6p.)