Atera Formation

Atera Formation (Katada and Isomi, 1958) Wakita and Koido, 1994

Invalid synonym: Shirakawa Rhyolites, Ashitani Formation, Muroyama Formation, Uto Formation, Shirakawaguchi Formation, Hidagawa Formation, Wara Formation

Type locality: Ateragawa river, Okuwa city, Kiso county, Nagano prefecture
Volcanic rocks
Caldera
Late Cretaceous - Paleogene (71.5 Ma, K-Ar; 67.3 Ma, FT)
Intruded by: Tajima Vent-fill Breccia
Correlation: Aoya Tuff

Sedimentary facies: Lacustrine
Lithofacies: Tuffaceous sandstone, Tuffaceous mudstone, Tuffaceous conglomerate, Volcanic breccia, Lapilli tuff, Tuff, Crystalline tuff

Source: Tajima Vent-fill Breccia
Thickness: 0 - 400 m
Distribution (East - West): 40 km or more
Distribution (South - North): 50 km or more
Upper limit: Conformity (Takadaru Welded Tuff)
Lower limit: Unconformity (Yumoriyama-Kanayama Welded Tuff, Shimoyui Granodiorite Porphyry, Dokyo Granodiorite Porphyry, Kawamata Mass, Tajima Vent-fill Breccia), Abut unconformity (Mino Belt, Ako Welded Tuff)

Atera Formation
[ Upper ]
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Tajima Vent-fill Breccia
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[ Lower ]

Sequence IV (central Mikkaichi, Gifu pref.)
[ Upper ]
~~~~~~~~~~~~~~
Akadani Welded Tuff
~~~~~~~~~~~~~~
Tsumetadani Formation
~~~~~~~~~~~~~~
[ Lower ]

Sequence IV (eastern Mikkaichi, Gifu pref.)
[ Upper ]
~~~~~~~~~~~~~~
Genjidake Welded Tuff
~~~~~~~~~~~~~~
Mikkamachi Formtion
~~~~~~~~~~~~~~
[ Lower ]

Sequence IV (Takayama, Gifu pref.)
[ Upper ]
~~~~~~~~~~~~~~
Kuzogawa Welded Tuff
~~~~~~~~~~~~~~
Aoya Tuff
~~~~~~~~~~~~~~
[ Lower ]

Sequence IV (Southern area)
[ Upper ]
~~~~~~~~~~~~~~
Uguigawa Welded Tuff
--------------
Mayumitoge Welded Tuff
~~~~~~~~~~~~~~
Takadaru Welded Tuff
--------------
Atera Formation
--------------
[ Lower ]

Nohi Rhyolites
[ Upper ]
~~~~~~~~~~~~~~
Sequence VI
~~~~~~~~~~~~~~
Sequence V
~~~~~~~~~~~~~~
Sequence IV
~~~~~~~~~~~~~~
Sequence III
~~~~~~~~~~~~~~
Sequence II
~~~~~~~~~~~~~~
Sequence I
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Ateragawa river, Okuwa city, Kiso county, Nagano pref.; Yanagase - Setogawa river, Otaki city, Kiso county, Nagano pref.; Kurosawa, Kiso city, Kiso county, Nagano pref.; Kashimo - Tsukechi - Doai - Idenokojitani valley, Nakatsugawa city, Gifu pref.; Higashishirakawa city, Kamo county, Gifu pref.; Aoya, Asahi town, Takayama city, Gifu pref.; Wakatochidani valley - Ichiidani valley -Nigorikawadani valley - Akanda - Ogurogawa river, Osaka town, Gero city, Gifu pref.; Mount Tashiroyama - Shinzu - Muragimi - Mudodani, Shirakawa town, Kamo county, Gifu pref.; Kakura, Wara, Gujo city, Gifu pref.

Wakita and Koido (1994) Geology of the Gero District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 79p. (in Japanese with English abstract 5p.)
Mizutani and Koido (1992) Geology of the Kanayama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 111p. (in Japanese with English abstract 9p.)
Yamada and Kobayashi (1988) Geology of the Ontakesan District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 136p. (in Japanese with English abstract 9p.)
Kawada et al. (1988) Geology of the Hagiwara District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 82p. (in Japanese with English abstract 10p.)
Yamada et al. (1985) Geology of the Takayama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 111p. (in Japanese with English abstract 9p.)
Yamada (1961) Kashimo, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 25p. (in Japanese with English abstract 7p.)
Katada and Isomi (1958) Agematsu, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 38p. (in Japanese with English abstract 8p.)