Mageshidani Formation

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Mageshidani Formation Akahane, 1978

Invalid synonym: upper Hosogai Formation

Type locality: Mageshidani valley - Mount Sasagamine - Mount Otomiyama, Myoko city, Niigata prefecture
Sedimentary facies: Marine
Coherent formation
late Pliocene (3.8 Ma, FT)

Lithofacies: Sandy mudstone
Lithofacies (Minor): Sandstone, Felsic tuff

Thickness: ca. 350 - 500 m
Lower limit: Conformity (Buno Formation)

Otari, Nagano pref.
[ Upper ]
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Mageshidani Formation
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Buno Formation
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Rokugo Formation
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Nagasaki Formation
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Tenguharayama Formation / Otarionsen Formation
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[ Lower ]

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

Distribution: Mageshidani valley - Mount Sasagamine - Mount Otomiyama, Myoko city, Niigata pref.; Ottatezawa creek - Maematsuozawa creek, Otari city, Kitaazumi county, Nagano pref.
Tephra: Mgs10

Nagamori et al. (2010) Geology of the Kotaki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 130p. (in Japanese with English abstract 4p.)
Nakano et al. (2002) Geology of the Shiroumadake District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 105p. (in Japanese with English abstract 5p.)