Tadrart Fm
Period:
Devonian
Age Interval:
Lochkovian-Emsian
Province:
Murzuq Basin, Ghadames Basin, Al Kufrah Basin
Type Locality and Naming
The Tadrart Formation was introduced by Burollet (1960). Its type section is at Takharkhouri pass along the eastern margin of Wadi Wan Kasa.
Synonym:
References: Burollet, 1960; Klitzsch, 1965; Klitzsch, 1969; Grubic et al., 1991; Pierobon, 1991
Lithology and Thickness
Tadrart displays 310m of continental to subcontinental sandstones at the Type Section. The formation has the shape of a thick lens deposited south of AI Qarqaf arch. The formation is thickest and best developed in the Al Awaynat area where it is 350m thick. The Tadrart Formation is made up of lenticular sandstone bodies representing filled channels within a braidedriver sequence with grain-size ranging from fine-grained to conglomeratic (Alkhalas, 2006).
Lithology Pattern:
Sandstone
Relationships and Distribution
Lower contact
It unconformably overlies the Akakus Fm. Sometimes termed the “Caledonian unconformity”, even though it is far from the Caledonian region.
Upper contact
It is conformably overlain by the Ouan Kasa Fm. in the Murzuq Basin, and overlain unconformably by the Binem Fm. in the Al Kufrah Basin.
GeoJSON
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Age
Generally Early Devonian (Lochkovian into late Emsian); but base is unconformity in some parts of basins (“Caledonian unconformity”. Onset is mid-Lochkovian at earliest (Craig, 2006; as used in SEPM summary).
Age Span:
Beginning stage:
Lochkovian
Fraction up in beginning stage:
0.5
Beginning date (Ma):
415.70
Ending stage:
Emsian
Fraction up in the ending stage:
0.7
Ending date (Ma):
399.16
Depositional setting
Braided river plain – floodplain deposystem (Adamson, 1991).
Depositional pattern:
Additional Information
Compiler:
Enam O. Obiosio, Solomon Joshua Avong and Henry Nasir Suleiman (2024) - Stratigraphic Lexicon compiled from the following books: