Oiwa Tuff Member

Oiwa Tuff Member (Matsumoto and Ikebe, 1958)

Invalid synonym: Oiwa Lapilli Tuff Member, Oiwa Tuff

Volcanic rocks
Miocene

Lithofacies: Andesite lapilli tuff
Lithofacies (Minor): Tuff breccia, Tuffaceous sandstone

Thickness: Several - ca. 20 m
Upper limit: Conformity, partly unconformity (Tsubono Formation)
Lower limit: Conformity (Fukuhira Formation)

Yatsuo Group (Uozu, Toyama pref.)
[ Upper ]
~~~~~~~~~~~~~~
Shakusenji Formation
--------------
Tsubono Formation
--------------
Oiwa Tuff Member
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Fukuhira Formation
~~~~~~~~~~~~~~
[ Lower ]

Yatsuo Group (Tateyama, Toyama pref.)
[ Upper ]
~~~~~~~~~~~~~~
Shakusenji Formation
--------------
Hosuikyo Tuff Breccia Member
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Oiwa Tuff Member
--------------
Mekka Pumiceous Tuff Member
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Zasunbo Alternation of Conglomerate, Sandstone and Mudstone Member
--------------
Iwaine Formation
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Oiwagawa river - Suyama - Goio, Kamiichi city, Nakaniikawa county, Toyama pref.

Sumi and Nozawa (1973) Geology of the Uozu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 104p. (in Japanese with English abstract 5p.)
Nozawa and Sakamoto (1960) Gohyakkoku, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 68p. (in Japanese with English abstract 10p.)