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Omagari carbonate islet

• Coherent formation
• Yezo forearc basin
• Late Cretaceous, Santonian - Campanian

• Sedimentary facies: Methane-seep carbonate, Chemosynthetic community
• Lithofacies (Main): Muddy limestone
• Lithofacies (Minor): Conglomerate, Tuffaceous sandstone, Siltstone

• Upper limit: Conformity
• Lower limit: Conformity

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

• Distribution: Abeshinai river, Hokkaido
• Fossils: Ammonoids (Gaudryceras tenuiliratum), Bivalves (Miltha), Tube worms
• Fossils (Diatoms): Gladius antiquus var. tenuis, Hemiaulus polymorphus?, Hemiaulus Rossicus, Hemiaulus sp., Palaria crenulata?, Palaria sp., Pterotheca sp., Stephanopyxis turries, Thalassiosiropsis? sp., Triceratium schulzii, Triceratium spp.

• Shimada et al. (2013) Jour. Geol. Soc. Japan, vol.119, no.6, pp.432-436 DOI