Tanihama Formation

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Tanihama Formation Fujimoto et al., 1951

Type locality: Kuwatori river, Arimagawa - Shimotsunako, Joetsu city, Niigata prefecture
Coherent formation
Rift basin sediments
Pliocene
Correlation: upper Nishiyama Formation

Sedimentary facies: Marine
Depth of water: Continental shelf
Lithofacies: Tuffaceous mudstone
Lithofacies (Bottom): Acidic tuff

Thickness: 370 - 420 m
Upper limit: Unconformity (Torigakubi Formation)
Lower limit: Tanihama Unconformity (Nadachi Formation)

Tanihama Formation
[ Upper ]
~~~~~~~~~~~~~~
Arimagawa Mudstone Member
--------------
Osuga Tuff Member
~~~~~~~~~~~~~~
[ Lower ]

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

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

Distribution: Arimagawa - Shimotsunako - Nadachi river, Joetsu city, Niigata pref.
Fossils (Omma-Manganji fauna):

Takano (2011) Jour. Geol. Soc. Japan, vol.117, no.4, pp.238-258 DOI
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.)