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Bou Bernous Formation
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Bou Bernous Fm base reconstruction

Bou Bernous Fm

Period: 
Devonian

Age Interval: 
Eifelian - Frasnian


Province: 
Tindouf Basin

Type Locality and Naming

Iguidi subbasin (exposed on northeast margin of Tindouf Basin)

Synonym:

References: Guerrak, 1989

[Fig. 1: Geological map of the Tindouf Basin region. (from Guerrak, 1989).]

[Fig. 2: Location of the Tindouf Basin Province, North Africa, and the six assessment units (AUs) (USGS, 2019).]

[Fig. 3: Stratigraphic column of the Tindouf Basin region (Guerrak, 1989).]

[Fig. 4: Stratigraphic correlation of the northern and southern flanks of the Tindouf Basin (Guerrak, 1989).]

[Fig. 5: Stratigraphic column of the study area (redrawn after Guerrak, 1988a).]


Lithology and Thickness

The Bou Bernous Fm is about 70m thick and is made up of shaley limestones that grade into silty limestones. The formation forms the lateral equivalent of the Middle Oued Talha, Upper Oued Talha, and Oued Tsabia formations of the Yetti Sub-basin (Guerrak, 1989).


Lithology Pattern: 
Clayey Limestone


Relationships and Distribution

Lower contact

Conformably overlies the Upper Fedj Mlehas Fm

Upper contact

Conformably underlies the Mecheri Fm

Regional extent

Extends through northern and southern flanks of the Tindouf Basin, and Iguidi subbasin (exposed on northeast margin of Tindouf Basin)


GeoJSON

{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[-6.64,28.93],[-5.14,29.21],[-3.93,29.03],[-4.06,28.43],[-5.01,27.48],[-5.54,26.81],[-5.81,25.73],[-6.31,24.91],[-7.71,23.68],[-8.19,23.2],[-10.26,22.65],[-6.64,28.93]]]]}}

Fossils


Age 

Eifelian - Frasnian

Age Span: 

    Beginning stage: 
Eifelian

    Fraction up in beginning stage: 
0.00

    Beginning date (Ma): 
394.30

    Ending stage: 
Frasnian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
371.10

Depositional setting


Depositional pattern:  


Additional Information


Compiler:  

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

Andrea Ciampalini, Francesca Garfagnoli, Benedetta Antonielli, Chiara Del Ventisette & Sandro Moretti (2012) Photo-lithological map of the southern flank of the Tindouf Basin (Western Sahara), Journal of Maps, 8:4, 453-464, DOI: 10.1080/17445647.2012.746947

Guerrak S. (1989): Time and space distribution of Palaeozoic oolitic ironstones in the Tindouf Basin, Algerian Sahara. In: Young, T. P. & Taylor, W. E. G. (eds), 1989: Phanerozoic Ironstones

Geological Society Special Publication 46, pp. 197-212

Guerrak S. (1988a): Geology of the Early Devonian oolitic iron ore of the Gara Djebilet field. Saharan Platform, Algeria. Ore Geology Reviews, (In Press).