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Onozawa Gravel

Invalid synonym: Anchiku Formation

• Coherent formation
• Upper: late Pleistocene, Last Glacial Period
• Lower: middle Pleistocene
• Correlation (Upper): Osakada Loam, Kakizawa Gravel
• Correlation (Lower): Osakada Gravel

• Sedimentary facies: Fluvial
• Sedimentary facies (Upper): Alluvial fan
• Sedimentary facies (Lower): Sedimentary basin-fill deposit
• Lithofacies (Upper): Interbedded sands and gravels
• Lithofacies (Upper, Minor): Clay, Pumice
• Lithofacies (Lower): Gravels
• Lithofacies (Lower, Minor): Sandy clay, Mud

• Thickness (Upper): 20 - 30 m
• Thickness (Lower): 100 m or thicker
• Upper limit: Unconformity (Hario Gravel)

• Distribution: Onozawa, Asahi city, Higashichikuma county, Nagano pref.

• Katada and Isomi (1964) Shiojiri, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 52p. (in Japanese with English abstract 10p.)