Chausuyama Welded Tuff Member

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Chausuyama Welded Tuff Member Akima Collaborative Research Group, 1971

Tephra
Pliocene - Pleistocene (3.78 - 2.91 Ma, K-Ar; 4.1 Ma, FT)
Correlation: Shiga Welded Tuff

Lithofacies: Tholeiite, Calc-alkaline
Lithofacies: Pyroxene andesite welded tuff
Lithofacies (Basal): Pumice tuff

Thickness: 30 m
Thickness (Basal): 30 cm
Upper limit: Unconformity (Upper part)
Lower limit: Conformity (Otogai Tuff Breccia Member)

Akima Formation
[ Upper ]
--------------
Upper part
~~~~~~~~~~~~~~
Chausuyama Welded Tuff Member
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Otogai Tuff Breccia Member
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Nagaiwa Lapilli Tuff Member
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Morikuma Volcanic Breccia Member
~~~~~~~~~~~~~~
[ Lower ]

Kirizumi volcano
[ Upper ]
--------------
Aimagawa Formation / Akima Formation
~~~~~~~~~~~~~~
[ Lower ]

Takasaki Group
[ Upper ]
--------------
Akima Formation
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Mount Chausu, Nishikamiakima, Annaka city, Gunma pref.

Geshi and Takeuchi (2012) Geology of the Haruna San District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 79p. (in Japanese with English abstract 3p.)