Lower subgroup Fm
Period:
Triassic
Age Interval:
Upper Triassic (Carnian), (15a, 15b)
Province:
Kurosegawa Belt- Shikoku
Type Locality and Naming
Kurosegawa Belt-western and central Shikoku
Synonym:
Lithology and Thickness
Composed of sandstone, mudstone and alternating beds of sandstone and mudstone, with conglomeratic sandstone
Lithology Pattern:
Sandy_claystone
Relationships and Distribution
Lower contact
Regionally, the schematic strat column indicates the next older unit as Kuma Fm
Upper contact
Regionally, the schematic strat column indicates the next younger unit as Upper subgroup Fm
Regional extent
Kurosegawa Belt-western Shikoku
GeoJSON
null
Fossils
Lower subgroup has yielded the bivalves Halubio, Tosapecten and the ammonoid Paratrachyceras (Tsujino et a1., 2013).
Age
Upper Triassic (Carnian)
Age Span:
Beginning stage:
Carnian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
237.00
Ending stage:
Carnian
Fraction up in the ending stage:
1.0
Ending date (Ma):
227.30
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.