Ounianga Fm
Period:
Jurassic, Cretaceous
Age Interval:
Kimmeridgian-Barremian
Province:
Al Kufrah Basin
Type Locality and Naming
The name Ounianga Formation was used by Wacrenier (1958) and De Lestang (1965, 1968) to describe continental Mesozoic sediments near the Libyan-Chad border. (Tawandros, 2011). [Middle formation of the Al Kufra Basin version of the Nubian Sandstone Gr.]
Synonym:
References: Tawadros, 2011
Lithology and Thickness
“The Formation is composed of white to multicolor, massive to cross-bedded, fine to medium-grained sandstones, less frequently coarse-grained clayey and congolmeratic with thin red shale beds at the base, and abundant silicified wood fragments (Wacrenier, 1958). Its thickness is about 400 m (1312 ft).” (Tawandros, 2011)
Lithology Pattern:
Fine-grained sandstone
Relationships and Distribution
Lower contact
It conformably overlies the Lakes Fm.
Upper contact
Conformably overlain by the Chieun Fm of assumed Aptian age.
Regional extent
Only the Al Kufrah Basin.
GeoJSON
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Fossils
Age
Base shown by Tawadros (2001) as equivalent to Messak Fm = base Kimm (used here) and “overlain by the Chieun Fm of assumed Aptian age” => top in Barremian.
Age Span:
Beginning stage:
Kimmeridgian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
154.78
Ending stage:
Barremian
Fraction up in the ending stage:
1.0
Ending date (Ma):
121.40
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).