Tahara Fm
Period:
Carboniferous
Age Interval:
Tournaisian
Province:
Murzuq Basin, Ghadames Basin
Type Locality and Naming
The Tahara Formation was established by Burollet and Manderscheid in 1967, and was refined by Massa, Termier and Termier in 1974. B 1-49 well in the southern Ghadamis Basin.
Synonym: It is also known as the Lower Mrar Fm. (see Fig. 7 of Fello, 2001).
References: Burollet and Manderscheid, 1967; Pierobon, 1991; Fello, 2001; Hallett, 2002
Lithology and Thickness
The formation was defined as a 60-70m shale-sandstone cycle from a type section in B 1-49 well in the southern Ghadames Basin. It outcrops in a small area to the northwest of Awaynat Wanin where two coarsening-upwards cycles are exposed separated by a hard ground (Hallett, 2002). The lower Tahara displays thin bedsets with lenticular wavy-bedded shale and very fine sandstone at the base grading upwards, in a cyclic fashion, into hummocky to cross-bedded sandstones. Each cycle is more than a few meters thick and is marked by intense bioturbation (Skolithos) and oxidized levels (commonly bearing ferruginous oolites) in the top part. The upper Tahara is quite similar. Topping the cycles are massive and sigmodal to tabular cross-bedded sandstones (Pierobon, 1991).
Lithology Pattern:
Sandstone
Relationships and Distribution
Lower contact
It conformably overlies the Awaynat Wanin Fm.
Upper contact
It is unconformably overlain by the Marar Fm.
Regional extent
It is present in both the Murzuq and Ghadames Basins.
GeoJSON
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Fossils
Age
Age Span:
Beginning stage:
Tournaisian
Fraction up in beginning stage:
0.00
Beginning date (Ma):
359.30
Ending stage:
Tournaisian
Fraction up in the ending stage:
1.0
Ending date (Ma):
346.73
Depositional setting
Shelf-shoreface succession in a storm-dominated environment.
Depositional pattern:
Additional Information
Compiler:
Enam O. Obiosio, Solomon Joshua Avong and Henry Nasir Suleiman (2024) - Stratigraphic Lexicon compiled from the following books: