Karasawagawa Formation

Karasawagawa Formation Mikami, 1955

Type locality: Karasawagawa river, Kiyokawa city, Aiko county, Kanagawa prefecture
Volcanic rocks
Oceanic arc of Paleo-Izu-Bonin arc
Mountain flank deposits of submarine volcanos and volcanic islands on Tanzawa mass
Middle Miocene (15.8 - 13.5 Ma, Calcareous nannofossils)

Sedimentary facies: Marine
Metamorphic facies: Prehnite-Pumpellyite
Lithofacies: Subaqueous volcaniclastics, Subaqueous lavas
Lithofacies: Basaltic - andesitic hyaloclastite, Epiclastic debrite and turbidite
Lithofacies: Basalt lapilli tuff, Basalt - Andesite lapilli tuff, Tuff
Lithofacies (Minor): Basalt - andesit lavas, Pillow lavas, Dacite tuff, Mudstone

Thickness: 900 - 2,200 m
Upper limit: Conformity
Lower limit: Conformity

Karasawagawa Formation
[ Upper ]
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Karasawa Tuff Member
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Nunokawa Volcanic Breccia Member
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[ Lower ]

Oyama Subgroup
[ Upper ]
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Karasawagawa Formation
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Hondanigawa Formation
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[ Lower ]

Tanzawa Group
[ Upper ]
~~~~~~~-------
Susugaya Subgroup
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Oyama Subgroup
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Togatake Subgroup
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[ Lower ]

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

Distribution: Karasawagawa river, Kiyokawa city, Aiko county, Kanagawa pref.; Osawa, Atsugi city, Kanagawa pref.; Hinata river - Mount Oyama, Isehara city, Kanagawa pref.

Ishikawa et al. (2016) Jour. Geol. Soc. Japan, vol.122, no.7, pp.291-304, DOI
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.)
Matsubara and Amano (2010) Jour. Geol. Soc. Japan, vol.116, no.3, pp.134-150 DOI
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.)