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Niitsuru Pyroclastic Flow Deposit

Invalid synonym: Kotsumaki Pyroclastic Deposit, Fj4 Pyroclastic Flow Deposit

• Tephra
• Pliocene (4.2 - 4.1 Ma, FT)

• Sedimentary facies: Terrestrial
• Sedimentary facies: Pyroclastic flow deposit
• Sedimentary facies (Bottom): Pyroclastic surge deposit
• Lithofacies: Orthopyroxene clinopyroxene hornblende-bearing biotite rhyolite
• Lithofacies: Pumiceous lapilli tuff, Tuff breccia
• Lithofacies (Bottom): Hornblende orthopyroxene clinopyroxene dacite tuff
• Lithofacies (Bottom, Minor): Accretionary lapilli
• Lithofacies (Debris avalanche deposit): Breccia
• Sedimentary structures (Bottom): Dune, Parallel stratification, Graded bedding, Reversed graded bedding
• Paleocurrent: Southwest to North

• Source: Uwaigusa caldera
• Host: Fujitoge Formation
• Thickness (Pyroclastic flow deposit): 8 - ca. 150 m
• Thickness (Pyroclastic flow deposit, Bottom): 5 - 15 m
• Thickness (Debris avalanche deposit): ca. 300 m
• Lower limit: Unconformity (Iriyamazawa Formation)

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

• Distribution: Mount Hakase, Fukushima pref.; Nojiri river, Tamanashi, Kaneyama city, Onuma county, Fukushima pref.; Mizunuma - Shirasawa river - Suireizawa?, Kaneyama city, Onuma county, Fukushima pref.; Hayato, Mishima city, Onuma county, Fukushima pref.

• Yamamoto et al. (2006) Geology of the Kitakata District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 63p. (in Japanese with English abstract 5p.)
• Yamamoto and Komazawa (2004) Geology of the Miyashita District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 71p. (in Japanese with English abstract 5p.)
• Yamamoto and Yoshioka (1992) Geology of the Wakamatsu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 73p. (in Japanese with English abstract 5p.)