Iwamuro Formation

Coherent formation
Early Jurassic
Correlation: Kuruma Formation
Intruded by: Sudagai Granite, Miocene quartz diorite

Sedimentary facies: Marine
Sedimentary facies: Continental shelf

Katashina Belt
[ Upper ]
/--/--/--/--/-
Tokurazawa Formation
/--/--/--/--/-
Iwamuro Formation
/--/--/--/--/-
Okutone Group
/--/--/--/--/-
[ Lower ]

Joetsu Belt
[ Upper ]
/--/--/--/--/-
Katashina Belt
/--/--/--/--/-
Tanigawadake Belt
/--/--/--/--/-
[ Lower ]

Maizuru Belt
[ North ]
/--/--/--/--/-
North zone
/--/--/--/--/-
Central zone
/--/--/--/--/-
South zone
/--/--/--/--/-
[ South ]

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

Distribution: Hodonosawa - Tenjin ridge - Tanigawa river, - Mount Ichinokura Minakami city, Tone county, Gunma pref.; Mount Bunodake, Yuzawa city, Minamiuonuma county, Niigata pref.

Takahashi et al. (2004) Geology of the Suhara District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 80p. (in Japanese with English abstract 4p.)
Chihara and Komatsu (1992) Geology of the Hakkaisan District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 107p. (in Japanese with English abstract 8p.)
Chihara et al. (1981) Geology of the Echigo-Yuzawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 108p. (in Japanese with English abstract 8p.)