Yataro Formation

Yataro Formation (Mikami, 1955) Aoike, 1997

Type locality: Yataro river, Jike - Yataro, Susugaya, 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
Late Miocene (11.5 - 11.0 Ma; 10.9, 8.64 Ma, FT; Calcareous nannofossils)

Sedimentary facies: Marine
Sedimentary facies: Pumiceous turbidite, No terrestrial sediments supplied
Sedimentary facies (Minor): Epiclastic turbidite
Metamorphic facies: Prehnite-Pumpellyite
Depth of water: Bathyal or deeper (Foraminifera)
Lithofacies: Subaqueous volcaniclastics, Subaqueous lavas
Lithofacies: Basalt - andesite lapilli tuff, Volcanic sandstone, Tuffaceous mudstone, Volcnaic mudstone, Sandstone, Mudstone
Lithofacies (Minor): Dacite pumice tuff
Sedimentary structures: Upward-fining

Thickness: 50 - 1,500 m
Upper limit: Conformity, partly Unconformity (Jike Formation)
Lower limit: Bottom of the horizon intercalating mudstone and fine-grained tuff
Lower limit: Conformity (Osawa Formation)

Susugaya Subgroup
[ Upper ]
~~~~~~~-------
Yataro Formation
--------------
Osawa Formation
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Fudojiri Formation
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[ Lower ]

Tanzawa Group
[ Upper ]
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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: Jike - Yataro, Susugaya - Karasawa forest road - Hemuro river - Bessho, Kiyokawa city, Aiko county, Kanagawa pref.; Mount Sekirosan, Sagamihara city, Kanagawa pref.; Lake Miyagase, Kanagawa pref.; Shijuhasse river, Hadano city, Kanagawa pref.
Fossils (Calcareous nannofossils): Discoaster quinqueramus

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.)