Niihama Formation

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Niihama Formation Noda et al., 2010

Type locality: southern Kussaki, Go, Niihama city, Ehime prefecture
Coherent formation
Izumi sedimentary basin
Forearc basin associated with strike-slip fault related to Median Tectonic Line
Late Cretaceous, middle Campanian (79.1 Ma, FT; Radiolarians)

Sedimentary facies: Main filling of the sedimentary basin
Lithofacies: Interbedded turbidite and mudstone
Lithofacies (Top): Mudstone
Lithofacies (Upper): Interbedded sandstone and mudstone
Lithofacies (Middle): Sandstone
Lithofacies (Lower): Conglomerate
Lithofacies (Bottom): Sandstone
Lithofacies (Minor): Felsic tuff
Sedimentary structures: Flute marks, Groove marks, Imbricate structure, Slump structure
Paleocurrent: East-Northeast to West-Southwest

Thickness: 2,000 m or thicker
Thickness (Middle): 1,000 m
Thickness (Lower): 500 m
Thickness (Bottom): 50 m
Lower limit (East): Conformity (Kussaki Formation)
Lower limit (West): Conformity (Isoura Formation)

Main facies (Niihama region)
[ Upper ]
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Niihama Formation
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Isoura Formation
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[ Lower ]

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

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

Distribution: Kussaki, Go - Hoshigoe village, Niihama city, Ehime pref.; Shimoshimayama, Saijo city, Ehime pref.; Tenma, Doi village, Shikokuchuo city, Ehime pref.

Noda et al. (2010) Jour. Geol. Soc. Japan, vol.116, no.2, pp.99-113 DOI