Chieun Fm
Period:
Cretaceous
Age Interval:
Aptian
Province:
Al Kufrah Basin
Type Locality and Naming
The name Chieun Formation was applied by De Lestang (1965, 1968) to designate continental Mesozoic deposits exposed near the Libyan-Chad border in the southwestern Kufrah Basin. [lower-Upper formation of the Al Kufra Basin version of the Nubian Sandstone Gr.]
Synonym:
References: Tawadros, 2011
Lithology and Thickness
Consists of variegated silty shales with lenses of fresh-water (limnic) limestones.
Lithology Pattern:
Continental marl
Relationships and Distribution
Lower contact
It conformably overlies the Ounianga Fm.
Upper contact
Conformably overlain by the Tekro Fm.
Regional extent
Only the Al Kufrah Basin.
GeoJSON
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Fossils
Age
“Its age is assumed to be Jurassic-Lower Cretaceous based on its stratigraphic position. However, the present writer assigns the Chieun Fm an Aptian age based on its correlation with the middle variegated shale unit of the Nubian sandstones in the Sirte Basin.
Age Span:
Beginning stage:
Aptian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
121.40
Ending stage:
Aptian
Fraction up in the ending stage:
1.0
Ending date (Ma):
113.20
Depositional setting
Depositional pattern:
Additional Information
Compiler:
Enam O. Obiosio, Solomon Joshua Avong and Henry Nasir Suleiman (2024) - Stratigraphic Lexicon compiled from the following books:
Tawadros, 2011, Geology of North Africa (book).