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Komanoma Formation Yoneyama Research Group, 1973

• Type locality: Ukawa river, Shimizutani - Komanoma, Kashiwazaki city, Niigata prefecture
• Coherent formation
• Pleistocene (2.55, 2.31 Ma, K-Ar)
• Correlation: Uonuma Formation

• Lithofacies (Upper): Olivine-bearing hornblende two-pyroxene andesite lava, Pyroclastic rocks
• Lithofacies (Middle): Hornblende pyroxene andesite volcanic mudflow deposit
• Lithofacies (Lower): Conglomerate, Sandstone, Siltstone
• Lithofacies (Lower, Minor): Tuff, Lignite

• Thickness (Upper): 160 m or thicker
• Thickness (Middle): 70 m
• Thickness (Lower): 110 m
• Upper limit: Unconformity (Kume Conglomerate)
• Lower limit: Unconformity (Asojima Formation, Yoneyama Formation)

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

• Distribution: Ukawa river, Shimizutani - Komanoma, Kashiwazaki city, Niigata pref.; Orii river, Orii, Kashiwazaki city, Niigata pref.
• Fossils (Plants): Alnus sp., Corbicula japonica, Fagus sp., Juglans cinerea, Menyantes sp. (Seeds)
• Tephra: Komanoma Tephra, Irajima Tuff

• Kobayashi et al. (1989) Geology of the Okanomachi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 112p. (in Japanese with English abstract 5p.)