Chayagahara Mudstone Member

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Chayagahara Mudstone Member Akahane, 1975

Type locality: Chayagahara, Joetsu city, Niigata prefecture
Coherent formation
late Pliocene

Lithofacies: Tuffaceous siltstone
Lithofacies (Minor): Sandstone, Acidic tuff, Gravel-bearing mudstone, Interbedded sandstone and mudstone, Scoria

Thickness: 50 - 60 m
Upper limit: Unconformity (Marine terrace deposit)
Lower limit: Conformity (Torigakubi Conglomerate Member)

Torigakubi Formation
[ Upper ]
~~~~~~~~~~~~~~
Chayagahara Mudstone Member
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Torigakubi Conglomerate Member / Eboshiyama Volcanic Rocks
~~~~~~~~~~~~~~
[ Lower ]

Joetsu Group
[ Upper ]
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Torigakubi Formation
~~~~~~~~~~~~~~
Tanihama Formation
~~~~~~~~~~~~~~
Nadachi Formation
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[ Lower ]

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

Distribution: Chayagahara - Yakushido - Sankakudai, Joetsu city, Niigata pref.

Akahane and Kato (1989) Geology of the Takada-Seibu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 89p. (in Japanese with English abstract 3p.)