[ Top ] [ Japanese ]

Otagirigawa Pyroclastic Flow Deposit Hayatsu, 1985

• Type locality: Tsubame hot spring - Myokoohashi bridge, Otagiri river, Myoko city, Niigata prefecture
• Volcanic rocks
• late Jomon period, Holocene (4,630, 3,690 yBP, ¹⁴C)

• Lithofacies (Upper): Pyroclastic flow deposit
• Lithofacies: Hornblende hypersthene andesite pyroclastic rocks

• Source: Myoko volcano
• Thickness: ca. 10 cm - 70 m or thicker
• Lower limit: Unconformity (Yashirogawa Debris Avalanche Deposit, Akakura Pyroclastic Flow Deposit)

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

• Distribution: Tsubame hot spring - Myokoohashi bridge, Otagiri river, Myoko city, Niigata pref.; Sekikawa river, Kobarashinden - Oshika, Myoko city, Niigata 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.)