Nishikozawa Formation

Nishikozawa Formation Muto, 1956

Type locality: Nishikozawa, Higashinaruse city, Okachi county, Akita prefecture
Coherent formation
Miocene

Sedimentary facies: Marine
Lithofacies: Tuffaceous siltstone
Lithofacies (Minor): Tuff, Shale

Thickness: 500 - 700 m
Lower limit: Conformity (Oarasawa Formation), Interfingered (Oidegawa Formation)

Nishikozawa Formation
[ Upper ]
--------------
Tozan Rhyolite Member
'''''''/,,,,,,
[ Lower ]

Mount Yakeishidake, Iwate pref.
[ Upper ]
~~~~~~~~~~~~~~
Mizuyama Formation
~~~~~~~~~~~~~~
Orose Formation
--------------
Maekawa Formation
--------------
Nishikozawa Formation
'''''''/,,,,,,
Oidegawa Formation
--------------
Oarasawa Formation
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Nishikozawa - Mount Futomori? - Kashiwa pass - Mount Tozan - Mount Gorozawa, Higashinaruse city, Okachi county, Akita pref.
Fossils: Brachiopoids (Terebratulina sp.), Sponges (Makiyama chitanii)
Fossils (Shellfishes): Chlamys sp., Conchocele sp., Lucinoma acutilineata, Ostrea sp., Trophonopsis sp.
Fossils (Foraminifera): Bulimina pupoides, Cassidulina sp., Cibicides altamiraensis, Cyclammina cancellata, Cyclammina japonica, Cyclammina orbicularis, Cyclammina pusilla, Dentalina sp., Dyocibicides sp., Globigerina sp., Haplophragmoides cf. trullisatum, Martinottiella communis, Nonion nicobarense, Nonion pompilioides, Planulina nipponica, Trochammina sp.

Kitamura (1965) Yakeishi-dake, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 40p. (in Japanese with English abstract 8p.)