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Upper Fedj Mlehas Formation
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Upper Fedj Mlehas Fm base reconstruction

Upper Fedj Mlehas Fm

Period: 
Early Devonian

Age Interval: 
Lochkovian – Emsian


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 Upper Fedj Mlehas Fm is about 70m thick, and is characterised from base to top by silty sandstones that grade into shaley limestone. It is the lateral equivalent of the Djebilet Gr and Lower Oued Talha Fm (Guerrak, 1989).


Lithology Pattern: 
Sandy limestone


Relationships and Distribution

Lower contact

Conformably overlies the Lower Fedj Mlehas Fm

Upper contact

Conformably underlies the Bou Bernous 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 

Lochkovian – Emsian

Age Span: 

    Beginning stage: 
Lochkovian

    Fraction up in beginning stage: 
0.00

    Beginning date (Ma): 
419.00

    Ending stage: 
Emsian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
394.30

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).