Nagaiwa Fm
Period:
Carboniferous
Age Interval:
Bashkirian-Moscovian, (8c)
Province:
South Kitakami Belt-the Hikoroichi-Setamai district
Type Locality and Naming
Synonym:
Lithology and Thickness
It consists of massive limestone or limestone with siliceous nodules and sometimes intercalated pyroclaetic rocks.
[Figure 1: Stratigraphy of the Palaeozoic of the South Kitakatmi Belt, NE Japan (after M. Ehiro et al., 2016)]
Lithology Pattern:
Limestone
Relationships and Distribution
Lower contact
Regionally, the schematic strat column indicates the next older unit as Onimaru Fm
Upper contact
Regionally, the schematic strat column indicates the next younger unit as Sakamotozawa Fm
Regional extent
GeoJSON
null
Fossils
The Nagaiwa Formation is divided into the Millerella and Profusulinella zones (fusualinoideans; Kobayashi 1973) or Declinognathodus noduliferus and Idiognathoides sulcatus zones (conodont; Minato et al., 1979)
Age
It is dated as Serpukhovian-Moscovian
Age Span:
Beginning stage:
Serpukhovian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
330.34
Ending stage:
Moscovian
Fraction up in the ending stage:
1.0
Ending date (Ma):
307.02
Depositional setting
Depositional pattern:
Additional Information
Compiler:
Moreno, T., WALLIS, S., Kojima, T. & Gibbons, W. (Eds) 2016. The Geology of Japan. Geological Society. London. 1-24.