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Obaradai Sand and Gravel Formation (Hashirimizu Research Group, 1965) Machida, 1971

Invalid synonym: Obaradai Terrace Deposit

• Type locality: Obaradai, Yokosuka city, Kanagawa prefecture
• Coherent formation
• late Pleistocene (ca. 80 ka)
• Correlation: 3rd-a Terrace Deposit (Kakuda), Middle III Terrace Deposit (Somanakamura), Middle II Terrace Deposit (Haramachi), Middle III Terrace Deposit (Naraha), Zengyo Gravel, Oshika Gravel Bed, Hatsushima I Terrace Deposit, Kasana Terrace Deposits

• Sedimentary facies: Terrestrial
• Sedimentary facies: Alluvial fan
• Sedimentary facies (Basal): Lag
• Lithofacies: Sands, Gravels, Clay

• Thickness: 2 - 5 m
• Upper limit: Conformity (Shimosueyoshi Loam), Unconformity (MusashinoLoam)
• Lower limit: Unconformity (Tsurumi Formtion, Shimosueyoshi Formtion, Miyata Formation, Yokosuka Formation)

• Distribution: Obaradai - Yoshii - Nagai, Yokosuka city, Kanagawa pref.

• Eto et al. (1998) Geology of the Yokosuka District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 128p. (in Japanese with English abstract 3p.)
• Oka et al. (1984) Geology of the Tokyo-Seinambu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 148p. (in Japanese with English abstract 7p.)
• Mitsunashi and Kikuchi (1982) Geology of the Yokohama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 105p. (in Japanese with English abstract 4p.)
• Kodama et al. (1980) Geology of the Misaki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 38p. (in Japanese with English abstract 3p.)
• Oka et al. (1979) Geology of the Fujisawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 111p. (in Japanese with English abstract 5p.)