Tomogashima Formation

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Tomogasihma Formation Ishigami and Yoshimatsu, 1972

Type locality: Tomogashima island, Wakayama city, Wakayama prefecture
Coherent formation
Izumi sedimentary basin
Forearc basin associated with strike-slip fault related to Median Tectonic Line
Late Cretaceous, Maastrichtian

Sedimentary facies: Main filling of the sedimentary basin
Lithofacies: Turbidite, Channel deposit
Lithofacies: Interbedded sandstone and mudstone, Interbedded conglomerate and sandstone
Lithofacies (Minor): Felsic tuff
Sedimentary structures: Flute marks, Groove marks, Load structure, Current ripples, Slump structures
Paleocurrent: from Northeast to Southwest

Thickness: ca. 720 - 780 m

Main facie (Izumi mountains, Wakayama pref.)
[ upper ]
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Kokawa Formation
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Iwade Formation
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Shintachi Formation
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Kada Formation
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Tomogashima Formation
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[ Lower ]

Izumi Group
[ North ]
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Northern marginal facies
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Main facies
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Southern facies
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[ South ]

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

Distribution: Okinoshima island - Chinoshima island, Wakayama city, Wakayama pref.
Fossils: Ammonoids (Baculites regina), Shellfishes (Acila sp., Portlandia izumensis, Nanovavis sp.), Achaeozostera sp.

Miyata et al. (1993) Geology of the Wakayama and Ozaki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 68p. (in Japanese with English abstract 4p.)