Okago Formation

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Okago Formation (Ehiro, 1979) Ehiro and Bando, 1980

Type locality: Okago river, Okago, Fujisawa town, Ichinoseki city, Iwate prefecture
Coherent formation
Permian
Intruded by: Shinchitoge Gabbro
Correlation: Toyoma Formation

Sedimentary facies: Marine
Lithofacies: Mudstone
Lithofacies (Lower, Minor): Sandstone
Sedimentary structures: Cross stratification, Current ripples

Thickness: 800 - 1,100 m
Upper limit: Conformity (Senmatsu Formation), Unconformity (Hiraiso Formation)
Lower limit: Conformity (Shinden Formation, Higashifukakaya Formation)

South Kitakami Belt (Fujisawa - Okago)
[ Upper ]
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Senmatsu Formation
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Okago Formation
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Shinden Formation
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Higashifukakaya Formation
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Nishikori Formation
?--?--?--?--?-
[ Lower ]

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

Distribution: Okago river, Okago, Fujisawa town, Ichinoseki city, Iwate pref.
Fossils: Cephalopods (Eumedlicottia sp., Xenodiscus cf. carbonarius)
Fossils (Shellfishes): Astartella toyomaensis, Euphemitopsis kitakamiensis Pseudopermophorus uedai

Takeuchi and Mikoshiba (2002) Geology of the Senmaya District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 76p. (in Japanese with English abstract 3p.)
Takeuchi and Kaneko (1996) Geology of the Shizugawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 93p. (in Japanese with English abstract 5p.)