Kawauchi Fm
Period:
Silurian
Age Interval:
Middle-Late Silurian (Sheinwoodian), (8c)
Province:
South Kitakami Belt-the Hikoroichi-Setamai district
Type Locality and Naming
Synonym:
Lithology and Thickness
Limestone, Shale, Sandstone-Shale alternation. It consists mainly of limestone with basal arkose, and is associated with calcareous mudstone in the upper part.
[Figure 1: Stratigraphy of the Palaeozoic of the South Kitakatmi Belt, NE Japan (after M. Ehiro et al., 2016)]
Lithology Pattern:
Sandy limestone
Relationships and Distribution
Lower contact
The basal arkose unconformably covers the Hikami plutonic basement (Hikami Granite Fm) (Murata et al., 1974, 1982; Kitakami Paleozoic Research Group 1982).
Upper contact
Regionally, the schematic strat column indicates the next younger unit as Ono Fm
Regional extent
GeoJSON
null
Fossils
It has yielded many corals (Schedohalysites, Falsicatenipora, Favosites, Heliolites, etc.)
and trilobites (Encrinurus)
Age
It is considered to be Middle-Late Silurian in age (Kato et al. 1980).
Age Span:
Beginning stage:
Sheinwoodian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
432.93
Ending stage:
Ludfordian
Fraction up in the ending stage:
1.0
Ending date (Ma):
422.73
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.