Omosu Formation

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Omosu Formation Yamauchi et al., 2009

Type locality: Omosu - Fukuura tunnel - Kurotakiiwa, Okinoshima city, Oki county, Shimane prefecture
Volcanic rocks
late Miocene (6.3, 5.4 Ma, K-Ar; 6.8 Ma, Rb-Sr; 3.9 Ma, FT)
Intruded by: Hei Trachyte

Lithofacies: Rhyolite, Trachyte
Lithofacies: Lava, Pyroclastic rocks
Lithofacies (Minor): Shoshonite, Andeiste

Upper limit: Unconformity (Mukogaoka Formation, Misaki Basalt, Saigo Basalt), Abut unconformity (Shirashimazaki Basalt, Saigo Basalt)
Lower limit: Conformity (Tsuma Formation), Unconformity (Kumi Formation)

Omosu Formation
[ Upper ]
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Upper part
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Middle part
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Lower part
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[ Lower ]

Oki-Dogo island, Shimane pref.
[ Upper ]
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Omosu Formation
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Tsuma Formation
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[ Lower ]

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

Distribution: Omosu - Fukuura tunnel - Kurotakiiwa, Okinoshima city, Oki county, Shimane pref.

Yamauchi et al. (2009) Geology of the Saigo District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 118p. (in Japanese with English abstract 3p.)