Ouan Kasa Fm
Period:
Devonian
Age Interval:
Emsian - Eifelian
Province:
Murzuq Basin, Ghadames Basin
Type Locality and Naming
The Ouan Kasa Formation was first described by Borbhi and Chiesa (1940) in Wadi Wan Kasa. It is also known as the Kasa Fm in the Ghadames Basin.
Synonym: Quan Qasa (Craig, 2006; used in SEPM)
References: Chiesa, 1940; Castro et al., 1985; Pierobon, 1991; Alkhalas, 2006
Lithology and Thickness
In Klitzsch's type section at Takharkhouri it reaches a thickness of 43m. It is characterised by thin, coarsening-upward sequences with wavy lenticular and flaser-bedded, occasionally bioturbated siltstones and fine-grained sandstones, grading into tabular cross-bedded sandstone at the top (Fello, 2001).
Lithology Pattern:
Sandstone
Relationships and Distribution
Lower contact
It conformably overlies the Tadrart Fm.
Upper contact
It is unconformably overlain by the Awaynat Wanin Fm.
Regional extent
It is present in the Murzuq and Ghadames Basin.
GeoJSON
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Fossils
Age
late Emsian through Eifelian (but Craig, 2006 – used in SEPM summary – suggests onset of the overlying Awaynat Wanin Fm might be as early as base-Eifelian.
Age Span:
Beginning stage:
Emsian
Fraction up in beginning stage:
0.7
Beginning date (Ma):
399.16
Ending stage:
Eifelian
Fraction up in the ending stage:
1.0
Ending date (Ma):
385.30
Depositional setting
The formation accumulated in a low-energy setting ranging from brackish lagoon to shallow sublittoral and offshore bar environments (Alkhalas, 2006).
Depositional pattern:
Additional Information
Compiler:
Enam O. Obiosio, Solomon Joshua Avong and Henry Nasir Suleiman (2024) - Stratigraphic Lexicon compiled from the following books: