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Oujeft Gr
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Oujeft Gr base reconstruction

Oujeft Gr

Period: 
Ordovician

Age Interval: 
Early Ordovician


Province: 
Taoudeni Basin

Type Locality and Naming

This formation is mainly in the western portion (e.g., Adrar and Hohd sub-basins) of the Taoudeni Basin, which a vast intracratonic sedimentary basin spanning parts of Mauritania, Mali, Algeria, Burkina Faso and Guinea.

Synonym:

References: Martin-Monge et al., 2016

[Fig. 1: Location of the Taoudeni Basin Province and the four assessment units defined in the study by Brownfield et al. (2015)]

[Fig. 2: The Taoudeni Basin (Taupin et al., 2017)]

[Fig. 3: Abolag-1 well, R well and Atar Group type section stratigraphy, facies description and correlation in the Taoudeni Basin, and organic richness profile in the Abolag-1 well (Claue,1981; Rooney et al.2009; Trompette,1973; Albert-Villanueva et al. 2016)]

[Fig. 4: Generalized stratigraphy of the Taoudeni Basin in Mauritania. Lithostratigraphic name equivalences are provided for the Adrar, Hank and Hodh depocentres. The major discontinuities are numbered and reference to global glacial and tectonic events is provided. (From Martin-Monge et al. (2016) as modified after Lahondere et al. (2003, 2005)]


Lithology and Thickness

The Oujeft Gr is made up of Sandstones. The Oujeft Gr. is about 700m thick in the Adrar province, and ~43m thick in the Hodh-Afolle province (Taylor and Giles, 2013). The Erg Cheg Gr is its equivalent in the Hank Subbasin.


Lithology Pattern: 
Sandstone


Relationships and Distribution

Lower contact

Unconformably overlies the Nouatil Gr (late Cambrian depositional hiatus – Martin-Monge et al., 2016)

Upper contact

Unconformably overlain by the Tichit Gr (Mid Ordovician depositional hiatus – Martin-Monge et al., 2016)

Regional extent

This formation is mainly in the western portion (e.g., Adrar-Hohd sub-basin) of the Taoudeni Basin


GeoJSON

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Fossils


Age 

Martin-Monge et al. (2016) summary figure schematically indicates a span of early half of the Ordovician (Tremadocian through Dapingian used here)

Age Span: 

    Beginning stage: 
Tremadocian

    Fraction up in beginning stage: 
0.00

    Beginning date (Ma): 
486.85

    Ending stage: 
Dapingian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
469.42

Depositional setting

fluviatile to marine depositional setting (Martin-Monge et al., 2016)


Depositional pattern:  


Additional Information


Compiler:  

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

Wenzhe, G. (2009): Hydrocarbon generation conditions and exploration potential of the Taoudeni Basin, Mauritania. Pet. Sci., 6: pp.29-37

Taylor, C. D. and Giles, S. A. (2013): Mineral Potential for Sediment-Hosted Copper Deposits in the Islamic Republic of Mauritania: Phase V, Deliverable 75. U.S. Geological Survey, Reston, Virginia

Martin-Monge, A., Baudino, R., Gairifo-Ferreira, L. M., Tocco, R., Badali, M., Ochoa, M., Haryono, S., Soriano, S., El Hafiz, N., Mez, J. H., Chacon, B., Brisson, I., Grammatico, G., Varade, R., and Abdallah, H. (2016): An unusual Proterozoic petroleum play in Western Africa: the Atar Group carbonates (Taoudeni Basin, Mauritania). In: Sabato Ceraldi, T., Hodgkinson, R. A. & Backe, G. (eds) Petroleum Geoscience of the West Africa Margin. Geological Society, London, Special Publications, 438, http://doi.org/10.1144/SP438.5

Bradley, D. C., Motts, H. A., Horton, J. D., Giles, Stuart, and Taylor, C. D. (2015): Geologic Map of Mauritania (Phase V, Deliverables 51a, 51b, and 51c), Chap. A1 of Taylor, C. D., ed., Second Projet de Renforcement Institutionnel du Sector Minier de la Republique Islamique de Mauritanie (PRISM-II): U.S. Geological Survey Open-File Report 2013-1280-A1, 3 pl., http://dx.doi.org/10.3133/ofr20131280