Nishiyatsushiro Group

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Nishiyatsushiro Group Otsuka, 1938

Invalid synonym: Misaka Group

Type locality: Kaitokiwa, Minobu city, Minamikoma county, Yamanashi prefecture
Volcanic rocks
middle Miocene
Contemporaneous heterotopic facies: Tanzawa Group
Intruded by: Ashikawa type, Shimobe Intrusive Rocks

Sedimentary facies: Marine
Sedimentary facies: Volcanic products, Deep sea sediments
Sedimentary facies: Bimodal volcanic activity (Submarine volcanos of Tholeiite basalt and Dacite) in back-arc basin (Back-arc rift)
Depth of water: Deep sea
Lithofacies (Basalt): Island arc tholeiite, Transitional MORB
Lithofacies: Basalt lava, Volcaniclastic rocks, Dacite submarine pyroclastic flow deposit

Upper limit: Conformity (Hara Formation), Unconformity (Akebono Formation)

western Minobu, Yamanashi pref.
[ Upper ]
--------------
Gotenyama Formation
?--?--?--?--?-
[ Lower ]

eastern Minobu, Yamanashi pref.
[ Upper ]
--------------
Tokiwa Formation
--------------
Furusekigawa Formation
?--?--?--?--?-
[ Lower ]

western Kofu, Yamanashi pref.
[ Upper ]
--------------
Kawaguchi Formation
--------------
Ashigawa Formation / Ichinose Formation
--------------
[ Lower ]

eastern Kofu, Yamanashi pref.
[ Upper ]
--------------
Ichikawadaimon Formation
--------------
Ashigawa Formation
--------------
[ Lower ]

eastern Fujikawa river, Yamanashi pref.
[ Upper ]
--------------
Nishinorigawa Formation
--------------
[ Lower ]

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

Distribution: Misaka mountains, Yamanashi pref.; Mount Kenashi, Yamanashi pref.

Ozaki and Sugiyama (2018) Geology of the Minobu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 169p. (in Japanese with English abstract 7p.)
Nagahata et al. (2015) Jour. Geol. Soc. Japan, vol.121, no.4, pp.141-146, DOI
Sugiyama and Matsuda (2014) Geology of the Nanbu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 134p. (in Japanese with English abstract 5p.)
Katada (1956) Kofu, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 27p. (in Japanese with English abstract 4p.)