Kotani Formation

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Kotani Formation

Invalid name: Tawara Subgroup

Type locality: Kotani, Kawamoto city, Ochi county, Shimane prefecture
Volcanic rocks
late Eocene - early Oligocene (34.0 - 28.0 Ma; 34.4 Ma, FT)
Intruded by: Granodiorite, Granite, Mihara body, Ijimi Granite

Lithofacies: Dacite pyroclastic flow deposit
Lithofacies: Pumiceous lapilli tuff, Tuff
Lithofacies (Minor): Accretionary lapilli-bearing pyroclastic surge deposit

Thickness: 500 - 1,000 m or thicker
Upper limit: Unconformity (Komatsuji Formation)
Lower limit: Unconformity (Sakurae Group)

Tamagawa stage volcanic rocks (Shimane pref.)
[ Young ]
~~~~~~~~~~~~~~
Sakurae Group
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Kotani Formation
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Kawamoto Granodiorite
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Komatsuji Formation
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Toburodani Formation
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[ Old ]

Sanin Belt
[ Young ]
~~~~~~~~~~~~~~
Tamagawa stage volcanic rocks
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Younger Inbi stage intrusive rocks
?--?--?--?--?-
Older Inbi stage intrusiv rocks
?--?--?--?--?-
Inbi stage volcanic rocks
~~~~~~~~~~~~~~
Mochigase stage intrusive rocks
?--?--?--?--?-
Mochigase stage volcanic rocks
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[ Old ]

------ Transitional, ~~~~~~ Intrusive, :::::: Fault, /--/-- Thrust, +__+__ Ground surface, ?--?-- Unknown

Distribution: Kotani - Kawakudari - Mihara - Kitasaki, Kawamoto city, Ochi county, Shimane pref.

Kano (2018) Jour. Geol. Soc. Japan, vol.124, no.10, pp.781-803 DOI
Kano et al. (2001) Geology of the Yunotsu and Gotsu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 129p. (in Japanese with English abstract 5p.)