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Felar Felar Formation
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Felar Felar Fm base reconstruction

Felar Felar Fm

Period: 
Ordovician

Age Interval: 
latest Ordovician = Hirnantian.


Province: 
Ahnet Basin

Type Locality and Naming

Synonym:

References: van Dijk et al., 2019.


Lithology and Thickness

Felar Felar Fm (Ahnet Basin) and M’Kratta El Golea Fm (Mouydir Basin) are made up of sandstones from the late-Ordovician glacial episode, and are the lateral equivalent of the Tamadjert Fm of the Reggane Basin and the Gara Louki Fm of the Illizi Basin (van Dijk et al., 2019).


Lithology Pattern: 
Coarse-grained sandstone


Relationships and Distribution

Lower contact

It unconformably overlies the Oued Saret Fm.

Upper contact

It is unconformably overlain by the Hot Shales Fm.

Regional extent

SW Algeria; 75,000 Km2


GeoJSON

{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[2.24,26.77],[2.5,26.91],[2.65,26.59],[2.84,27],[3.1,26.63],[3.46,26.4],[3.36,26.28],[3.58,25.55],[3.54,24.93],[3.6,24.34],[3.47,24.34],[3.23,24.68],[3.03,24.61],[3.17,23.93],[2.64,23.73],[2.38,23.94],[2.04,24.46],[1.92,25.72],[1.57,26.6],[1.63,27.17],[1.84,27.18],[1.84,27],[2.24,26.77]]]]}}

Fossils


Age 

Glacial episode(s) of latest Ordovician (Hirnantian)

Age Span: 

    Beginning stage: 
Hirnantian

    Fraction up in beginning stage: 
0.0

    Beginning date (Ma): 
445.21

    Ending stage: 
Hirnantian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
443.07

Depositional setting

Glacial interval


Depositional pattern:  


Additional Information


Compiler:  

Enam O. Obiosio, Solomon Joshua Avong and Henry Nasir Suleiman (2024) - Stratigraphic Lexicon compiled from the following books:

Wendt J., Kaufmann B., Belka Z., Korn D (2008): Carboniferous Stratigraphy and Depositional Environments in the Ahnet Mouydir Area (Algerian Sahara). In: Facies. DOI 10.1007/s10347-008-0176-y

Wendt J., Kaufmann B., Belka Z., Klug C. & Lubeseder S. (2006): Sedimentary evolution of a Palaeozoic basin and ridge system: the Middle and Upper Devonian of the Ahnet and Mouydir (Algerian Sahara). Geol. Mag. 143 (3) pp. 269–299. doi:10.1017/S0016756806001737

Derder M, E.M., Henry B., Amenna M., Bayou B., Djellit H., Guemache M. A., Hemmi A. (2009): New structural implications for the central Sahara (Algeria), from the revisited Upper Carboniferous “Hassi Bachir” Formation: Paleomagnetic constraints. Tectonophysics, 463: pp.69–76.

Perron P., Guiraud M., Vennin E., Moretti I., Portier E., L. Le Pourhiet, M. Konaté (2018): Influence of basement heterogeneity on the architecture of low subsidence rate Paleozoic intracratonic basins (Reggane, Ahnet, Mouydir and Illizi basins, Hoggar Massif). Solid Earth, 9: pp.1239-1275.