Oma Formation

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Oma Formation Uemura, 1962

Type locality: Northern seashore of Oma city, Shimokita county, Aomori prefecture
Coherent formation
Miocene
Correlation: Kozawa Formation
Intruded by: Oritoyama Basalt, Bentenjima Rhyolite

Sedimentary facies: Marine
Lithofacies: Shale
Lithofacies (Upper, Minor): Mudstone, Sandy tuff

Upper limit: Interfingered (Ikokuma Andesites)

Oma, Aomori pref.
[ Upper ]
~~~~~~~~~~~~~~
Ikokuma Andesites
'''''''/,,,,,,
Oma Formation
?--?--?--?--?-
[ Lower ]

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

Distribution: Cape Oma, Oma city, Shimokita county, Aomori pref.; Hebiura, Kazamaura city, Shimokita county, Aomori pref.
Fossils: Sponges (Makiyama chitanii), Foraminifera (Cyclamina sp.), Diatoms

Uemura (1962) Oma and Sai, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 39p. (in Japanese with English abstract 6p.)