Ako Formation

[ Top ] [ Japanese ]

Ako Formation Kishida and Wadatsumi, 1967

Volcanic rocks
Late Cretaceous (73 Ma, K-Ar)

Lithofacies: Rhyolite welded vitreous tuff
Lithofacies (Minor): Dacite tuff

Thickness: ca. 1,500 - 2,000 m
Upper limit: Unconformity (Tenkadaiyama Group)

Ako Formation
[ Upper ]
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Hatsutoji Member
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[ Lower ]

Aioi Group (Hyogo pref. - Okayama pref.)
[ Upper ]
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Ako Formation
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Tsurukamejobu Formation
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Tsurukamekabu Formation
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Kamigorijobu Formation
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Kamigorikabu Formation
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[ Lower ]

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

Distribution: Ako city - Aioi city, Hyogo pref.; Mitsu town, Tatsuno city, Hyogo pref.

Igi and Wadatsumi (1980) Geology of the Kamigori District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 74p. (in Japanese with English abstract 4p.)