Kokubudai Formation

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Kokubudai Formation

Volcanic rocks
Setouchi volcanic belt
Miocene (13.0 Ma, K-Ar)

Lithofacies: Calc-alkaline series
Lithofacies: Basaltic andesite, Andesite lava, Tuff breccia, Sanukitoid andesite lava
Structures: Platy joints

Lower limit: Conformity (Higashioku Formation)

Kokubudai Formation
[ Upper ]
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Maruyama Volcanic Rock Member
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Tsukumoyama Volcanic Rock Member
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Takinomiya Volcanic Rock Member
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Kitaura Volcanic Rock Member
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Inazumiyama Lava Member
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Shioyama Lava Member
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Sou Lava Member
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[ Lower ]

Sanuki Group
[ Upper ]
~~~~~~~~~~~~~~
Kokubudai Formation
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Higashioku Formation
~~~~~~~~~~~~~~
[ Lower ]

Setouchi Volcanic Rocks (Sanuki, Kagawa pref.)
[ Upper ]
~~~~~~~~~~~~~~
Sanuki Group
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Mount Shippozan - Kareitoge pass - Mount Katabukiyama, Mitoyo city, Kagawa pref.; Inazumibashi bridge - Ibukijima island - Mount Tsukumoyama - Mount Maruyama, Kanonji city, Kagawa pref.

Noda et al. (2021) Geology of the Ikeda District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 150p. (in Japanese with English abstract 5p.)
Noda et al. (2017) Geology of the Kan-onji District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 96p. (in Japanese with English abstract 4p.)