Higashibara Formation

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Higashibara Formation (Ida, 1944) Itoigawa, 1955

Type locality: Maruhara mine, Higashibara, Hara, Yamaoka town, Ena city, Gifu prefecture
Coherent formation
Fluvio-lacustrine basin including Lake Tokai
middle Miocene, Serravallian - late Miocene, Tortonian (12 - 10 Ma, FT, U-Pb)
Correlation: Tokiguchi Porcelain Clay Formation, Seto Porcelain Clay Formation

Sedimentary facies: Braided river, Dammed lake
Sedimentary facies: Talus, Debris flow deposit, Alluvial fan, Flood plain, Channel, Marsh
Climate: Subtropical, Temperate
Lithofacies (Minor): Sands, Silt, Lignite

Thickness: 15 - 30 m
Lower limit: Unconformity (Maki Siltstone Member)

Tokai Group (Mizunami, Gifu pref.)
[ Upper ]
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Mashizume Formation
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Higashibara Formation
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[ Lower ]

Second Setouchi Supergroup (Mie pref. - Aichi pref.)
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Tokai Group
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[ Upper ]
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Second Setouchi Supergroup
?--?--?--?--?-
First Setouchi Supergroup
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[ Lower ]

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

Distribution: Higashibara, Hara, Yamaoka town, Ena city, Gifu pref.; Okawa - Mizukami, Sue town, Mizunami city, Gifu pref.; Okusa - Ransen, Sogi town, Toki city, Gifu pref.
Fossils (Pinus trifolia flora): Carya sp., Hemitrapa sp., Metasequoia sp., Nyssa sp., Pinus trifolia

Yamasaki et al. (2020) Geology of the Akechi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 120p. (in Japanese with English abstract 5p.)