Kokawa Formation

Kokawa Formation Research Group for MTL in West Kinki, 1981

Coherent formation
Izumi sedimentary basin
Forearc basin associated with strike-slip fault related to Median Tectonic Line
Late Cretaceous, Maastrichtian (72.2 Ma, FT)
Contemporaneous heterotopic facies: Nate Formation

Sedimentary facies: Main filling of the sedimentary basin
Lithofacies: Turbidite
Lithofacies: Interbedded sandstone and mudstone
Lithofacies (Minor): Mudstone, Interbedded conglomerate and sandstone
Sedimentary structures: Parallel stratification, Convolute foliation

Thickness: 2,900 - 3,900 m or thicker

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: Nishikawara - Nategawa river - Kuzuya - Mount Narutakamine, Kinokawa city, Wakayama pref.; Higashitani - Taira, Katsuragi city, Ito county, Wakayama pref.
Fossils: Inoceramus sp., Brachiopods
Tephra: t27 (72.2 Ma, FT)

Miyata et al. (2012) Jour. Geol. Soc. Japan, vol.118, Supplement, pp.37-52 DOI
Makimoto et al. (2004) Geology of the Kokawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 89p. (in Japanese with English abstract 4p.)
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.)
Itihara et al. (1986) Geology of the Kishiwada District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 148p. (in Japanese with English abstract 7p.)