Tsurunumagawa Pyroclastic Flow Deposit

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Tsurunumagawa Pyroclastic Flow Deposit

Tephra
Miocene (ca. 5.6 Ma, FT)

Lithofacies: Pyroclastic flow deposit
Lithofacies: Dacite lapilli tuff

Source: Jonoirizawa caldera
Host: Fujitoge Formation
Thickness: 400 m or thicker

Jonoirizawa Formation
[ Upper ]
~~~~~~~~~~~~~~
Lacustrine deposit = Post-caldera stage
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Tsurunumagawa Pyroclastic Flow Deposit / Debris avalanche deposit = Caldera-forming stage
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[ Lower ]

Jonoirizawa caldera
[ Upper ]
~~~~~~~~~~~~~~
Jonoirizawa Formation
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[ Lower ]

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

Distribution: Fukushima pref.

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 (1999) Geology of the Tajima District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 85p. (in Japanese with English abstract 8p.)