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Akasaka Formation Akahane, 1992

Invalid synonym: Keno Formation

• Type locality: Akasaka, Toyota, Nakano city, Nagano prefecture
• Coherent formation
• middle Pleistocene
• Correlation: Akashio Loam

• Sedimentary facies: Lacustrine
• Climate: Cool (Pollen)
• Lithofacies: Sands, Silt
• Lithofacies (Minor): Volcanic conglomerate

• Thickness: 20 - 30 m
• Lower limit: Unconformity (Yashiki Formation)

• Distribution: Akasaka, Toyota, Nakano city, Nagano pref.; Anata - Kenogawa, Nakano city, Nagano pref.; Naramoto - Keno, Iizuna city, Kamiminochi county, Nagano pref.
• Fossils (Pollen): Abies sp., Alnus sp., family Cyperaceae, family Gramineae, Larix sp., Picea sp., Thalictrum sp., Tsuga sp.

• Akahane et al. (1992) Geology of the Nakano District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 106p. (in Japanese with English abstract 4p.)