Okuyamada Formation

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Okuyamada Formation Ishida et al, 1954

Type locality: Okuyamadagawa river, Okuyamada, Ujitawara city, Tsuzuki county, Kyoto prefecture
Coherent formation
First Seto Inland Sea
Sedimentary basin in island arc
middle Miocene

Sedimentary facies: Marine
Lithofacies (Upper): Sandstone, Siltstone
Lithofacies (Lower): Conglomerate
Lithofacies (Lower, Minor): Sandstone, Sandy siltstone

Thickness: ca. 120 - 140 m
Thickness (Lower): Several - A few dozen m
Distribution (East - West): ca. 5 km
Upper limit: Bottom of the conglomerate-intercalating horizen overlying mudstone-dominant horizon
Upper limit: Conformity (Yuantani Formation), Unconformity (Ofuku Member, Otonoyama Formation)
Lower limit: Unconformity (Mino Belt)

Okuyamada Formation
[ Upper ]
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Kaya Member
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Miyamura Member
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Kawakami Member
~~~~~~~~~~~~~~
[ Lower ]

Tsuzuki Group
[ Upper ]
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Yuantani Formation
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Okuyamada Formation
~~~~~~~~~~~~~~
[ Lower ]

First Setouchi Supergroup (Kyoto pref.)
[ Upper ]
~~~~~~~~~~~~~~
Tsuzuki Group
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[ Lower ]

[ Upper ]
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Second Setouchi Supergroup
?--?--?--?--?-
First Setouchi Supergroup
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Okuyamada - Okuyamadagawa river - Karaiketoge pass, Ujitawara city, Tsuzuki county, Kyoto pref.
Fossils: Fish scales, Plants (Comptoniphyllum sp.)
Fossils (Shellfishes): Acila sp., Chlamys sp., Dosinia sp., Felaniella sp., Katelysia nakamurai, Lucinoma sp., Nipponomarcia sp., Nuculana kongiensis, Phaxas izumoensis, Vicaryella sp.

Wakita et al. (2013) Geology of the Kyoto-Tonambu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 124p. (in Japanese with English abstract 3p.)