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Obora Formation Yamada et al., 1985

Invalid synonym: Migakisuna Formation, Ogaya Formation

• Type locality: Obora town, Takayama city, Gifu prefecture
• Coherent formation
• Pliocene (3.1 Ma)

• Sedimentary facies (Minor): Subaqueous
• Sedimentary facies (Minor): Pyroclastic surge deposit
• Lithofacies: Gravels, Sands, Silt, Pumiceous volcanic ash, Volcanic ash
• Lithofacies (Minor): Peat, Rhyolite volcanic ash, Pumiceous lapilli tuff
• Sedimentary structures: Cross stratificaiton
• Paleocurrent: from East

• Thickness: ca. 10 - 30 m or less
• Upper limit: Unconformity (Nyukawa Pyroclastic Flow Deposit)
• Lower limit: Unconformity (Matsubara Gravel Bed, Matsumoto Gravel Bed, Kiriyama Gravel Bed)

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

• Distribution: Obora town, Takayama city, Gifu pref.; tateiwa, Asahi town, Takayama city, Gifu pref.; Machikata - Mukaiyama - Chayano, Nyukawa town, Takayama city, Gifu pref.; Onishi, Kuguno town, Takayama city, GIfu pref.
• Fossils (Pollen): Abies sp., Alunus sp., Artemisia sp., Betula sp., Carduoideae, Cyperaceae, Gramineae, Picea sp., Pinus sp., Salix sp., Sanguisorba sp., Taxodiaceae, Thalictrum sp., Tsuga sp.

• 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.)