Shiroiwa Formation

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Shiroiwa Formation Ikeda, 1975

Type locality: Hiramaru, Myoko city, Niiagata prefecture
Coherent formation
late Pliocene (ca. 3 Ma)
Correlation: lower Uragawara Formation, Seguchi Formation

Sedimentary facies: Shallow marine (Shellfishes)
Lithofacies: Sandy siltstone
Lithofacies (Minor): Sandstone

Thickness: 80 - 200 m
Upper limit: Conformity (Naradate Formation)
Lower limit: Transitional (Tamugigawa Formation)

Takada, Niigata pref.
[ Upper ]
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Naradate Formation
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Shiroiwa Formation / Uragawara Formation
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Tamugigawa Formation
'''''''/,,,,,,
Sugawa Formation
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Taruda Formation
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Matsunoyama Formation
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[ Lower ]

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

Distribution: Hiramaru, Myoko city, Niiagata pref.; Mount Hishigatake, Joetsu city, Niigata pref.; Akaike, Kiyosato ward, Joetsu city, Niigata pref.
Fossils (Shellfishes): Glycymeris sp., Ostrea sp., Pecten sp., Turritella sp.
Fossils (Trace fossils): Tube form

Takeuchi and Kato (1994) Geology of the Takada-tobu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 67p. (in Japanese with English abstract 5p.)