Hasawnah Fm
Period:
Cambrian
Age Interval:
Middle Cambrian to base of Ordovician
Province:
Murzuq Basin, Ghadames Basin, Al Kufrah Basin
Type Locality and Naming
Massa and Collomb (1960) introduced the Hasawnah Formation after Jabal Hasawnah. The formation outcrops in Eastern Libya to the west of Al Qarqaf and Dur Al Qussah (Fello, 2001). It is also called Hassaouna Fm (Gindre et al., 2012)
Synonym: Hassouna Fm (used in some columns for the Al Kufrah Basin); Hasawanah Fm (Craig, 2006; used in SEPM)
References: Massa and Collomb, 1960; Pierobon, 1991; Gindre et al., 2012
Lithology and Thickness
The Hasawnah Fm represents an extensive, blanket type, medium- to coarse-grained, highly cross-bedded sandstone, forming a 160-500 m thick, uniform sandy complex spread over vast portions of the Saharan platform (Pierobon, 1991).
Lithology Pattern:
Sandstone
Relationships and Distribution
Lower contact
Disconformably? overlies the Mourizidie Fm. (which is sometimes categorized together with the Basement Complex)
Upper contact
Unconformably overlain by the Ash Shabiyat Fm (Murzug Basin) and Hawaz Fm.
Regional extent
The Hasawnah Fm. (or Hassaouna Fm.) is present in the Murzuq, Ghadames, and the Al Kufrah Basins.
GeoJSON
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Fossils
Age
Probably beginning in the Middle Cambrian (base-Drumian used here) and extending to the base of the Ordovician. But the onset and the extent of an upper-unconformity are quite uncertain.
Age Span:
Beginning stage:
Drumian
Fraction up in beginning stage:
0.6
Beginning date (Ma):
502.10
Ending stage:
Tremadocian
Fraction up in the ending stage:
0.0
Ending date (Ma):
486.85
Depositional setting
The depositional setting of the Hasawnah Formation has been interpreted as braided-stream deposits due to their high sandstone/shale ratio (Pierobon, 1991).
Depositional pattern:
Additional Information
Compiler:
Enam O. Obiosio, Solomon Joshua Avong and Henry Nasir Suleiman (2024) - Stratigraphic Lexicon compiled from the following books:
Nuri Muhammed Fello (2001): Depositional Environments, Diagenesis and Reservoir Modelling of Concession NC115, Murzuq Basin, SW Libya. PhD Thesis submitted to The Department of Geological Sciences University of Durham.