Shigekurayama Volcanic Rock Member

Shigekurayama Volcanic Rock Member Kudo et al., 2011

Invalid synonym: Shigekurayama Formation, Niwazuki Pyroclastic Rocks, Yagigahana Formation, Yagigahana Lava Member

Volcanic rocks
Submarine lava domes, Dome-shaped shallow intrusions
Miocene (8.5 - 8.0 Ma, Diatoms, 8.3 - 5.8 Ma, FT)

Sedimentary facies: Submarine volcanic products
Sedimentary facies: Gravity flow deposit
Lithofacies: Biotite/Hornblende-bearing rhyolite lava, Hyaloclastite, Tuff, Lapilli tuff, Tuff breccia, Volcanic breccia, Intrusive rocks
Lithofacies (Minor): Mudstone, Tuffaceous mudstone, Tuffaceous sandstone
Sedimentary structures: Graded bedding, Parallel stratification

Thickness: ca. 350 m
Distribution (Diameter): 600 m or smaller
Upper limit: Conformity (Taira Formation), Unconformity (Lower III Terrace Deposit)

Minamiimogawa Formation
[ Upper ]
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Shigekurayama Volcanic Rock Member
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Sarugedake Volcanic Rock Member
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[ Lower ]

Kamo, Niigata pref.
[ Upper ]
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Minamiimogawa Formation
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Nanatani Formation
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Otani Formation
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Tonoiri Formation
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[ Lower ]

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

Distribution: Nanatani - Mount Yakushi, Kamo city, Niigata pref.; Ushiono, Sanjo city, Niigata pref.; Mount Takarayama, Gosen city, Niigata pref.

Kudo et al. (2011) Geology of the Kamo District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 162p. (in Japanese with English abstract 4p.)
Hiranaka et al. (2009) Jour. Geol. Soc. Japan, vol.115, no.4, pp.177-186 DOI