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Kirinai Formation

• Coherent formation
• Miocene

• Sedimentary facies (Upper): Marine
• Sedimentary facies (Lower): Shallow marine
• Water temperature: Warm ocean current (Shellfishes)
• Lithofacies (Upper): Basalt lava (Pillow lava, Hyaloclastite), Volcanic breccia, Tuff breccia, Tuff
• Lithofacies (Upper, Minor): Mudstone
• Lithofacies (Lower): Conglomerate, Sandstone
• Lithofacies (Lower, Minor): Acidic tuff, Basaltic andesite lava, Mudstone

• Thickness (Upper): 650 m
• Thickness (Lower): 150 - 200 m
• Upper limit: Unconformity (Osarubegawa Formation)
• Lower limit: Bottom of well-sorted sandstone bed
• Lower limit: Conformity (Makibuchi Formation)

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

• Distribution: Komata river - Ofunaki creek, Kitaakita city, Akita pref.; Urashinai river, Kazuno city, Akita pref.
• Fossils (Shellfishes): Cardita sp., Dosinia kaneharai, Fulgoraia sp., Glycymeris cfr. vestitoides, Patinopecten murayamai, Patinopecten yamasakii iwasakiensis, Pitar cfr. itoi, Placopecten protomollitus

• Sumi and Moritani (1973) Geology of the Yonaizawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 46p. (in Japanese with English abstract 4p.)