Karakuwa Gr
Period:
Jurassic, Cretaceous
Age Interval:
(Toarcian-Berriasian), (8h)
Province:
South Kitakami Belt-Central Sub-belt
Type Locality and Naming
the Karakuwa-Oshika Sub-belt
Synonym:
Lithology and Thickness
The Middle Jurassic-lowermost Cretaceous Karakuwa Group is divided into the Kosaba, Tsunakizaka, Ishiwaritoge, Mone, Kogoshio and Isokusa formations in conformably ascending order (Shiida 1940; Ehiro 1974; Takizawa 1985).
Lithology Pattern:
Sandstone
Relationships and Distribution
Lower contact
Regionally, the schematic strat column indicates the next older unit as Isokusa Fm
Upper contact
Regionally, the schematic strat column indicates the next younger unit as Yokonuma Fm
Regional extent
In the Karakuwa district of the Karakuwa-Oshika Sub-belt, Mesozoic rocks are represented by the Karakuwa Group and the Oshima Group within the wide, south-plunging Tsunakizaka Syncline.
GeoJSON
null
Fossils
Age
Toarcian-Berriasian
Age Span:
Beginning stage:
Toarcian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
184.20
Ending stage:
Valanginian
Fraction up in the ending stage:
1.0
Ending date (Ma):
132.60
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.