Kokuzo Basalt Member

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Kokuzo Basalt Member Uchimura Collaborative Research Group, 1953

Invalid synonym: Kokuzo Basalt Facies

Type locality: Kokuzo, Ueda city, Nagano prefecture
Volcanic rocks
middle Miocene (15.1 Ma, K-Ar)
Contemporaneous heterotopic facies: Hosoonotaki Volcanics Member

Lithofacies: Basalt pillow lava, Hyaloclastite
Paleocurrent: from Southeast to North - Northwest

Thickness: 300 m
Lower limit: Conformity (Reisenji Volcanics Member)

Uchimura Formation (Eastern part)
[ Upper ]
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Hosoonotaki Volcanics Member
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Kokuzo Basalt Member
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Reisenji Volcanics Member
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Takenoyu Volcanics Member
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Mozawa Tuffaceous Sandstone Member
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Takatozawa Volcanics Member
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[ Lower ]

Chushin Group
[ Upper ]
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Bessho Formation
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Uchimura Formation
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Moriya Formation
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[ Lower ]

northern Nagano pref.
[ Upper ]
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Hokushin Group
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Chushin Group
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[ Lower ]

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

Distribution: Kokuzo - Reisenjigawa river - Ogikubo - Tokorozawa pass - Takinosawa creek - Kakeyu Hotspring, Ueda city, Nagano pref.

Kosaka et al. (2022) Earth Science (Chikyu Kagaku), vol.76, no.4, pp.179-194 DOI
Harayama et al. (2009) Geology of the Matsumoto District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 63p. (in Japanese with English abstract 3p.)