Kosawa Formation

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Kosawa Formation (Suzuki, 1932) Nakaseko and Sawai, 1950

Type locality: Kaigarazawa creek, Kosawa, Sumida, Aikawa city, Aiko county, Kanagawa prefecture
Coherent formation
late Pliocene

Lithofacies: Sands
Lithofacies (Basal): Gravels
Lithofacies (Basal, Minor): Shell fragments
Sedimentary structures: Parallel stratification, Cross stratification

Thickness: 20 m
Upper limit: Conformity (Kanzawa Formation), Unconformity (Terrace deposit)
Lower limit: Unconformity (Sagamiko Group)

Nakatsu Group
[ Upper ]
~~~~~~~~~~~~~~
Shioda Formation
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Otsuka Formation
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Shimizu Formation
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Kanzawa Formation
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Kosawa Formation
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Kosawa, Sumida - Kumasaka, Nakatsu, Aikawa city, Aiko county, Kanagawa pref.; Kanzawa, Oshima, Midori ward, Sagamihara city, Kanagawa pref.
Fossils: Marine mammalina, Fishes, Shellfishes (Shallow marine), Foraminifera, Trace fossils

Ueki et al. (2013) Geology of the Hachioji District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 137p. (in Japanese with English abstract 6p.)