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Kreb-En-Naga Gr
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Kreb-En-Naga Gr base reconstruction

Kreb-En-Naga Gr

Period: 
Cambrian

Age Interval: 
Fortunian – Guzhangian


Province: 
Taoudeni Basin

Type Locality and Naming

This formation is mainly in the eastern portion (e.g., Hank sub-basin) 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 Kreb-En-Naga Gr. is made up of red pelites, sandstones, and calcareous mudstones (Taylor and Giles, 2013). It is made up of coarse-grained sandstone, red pelite, and calcareous mudstone; minor bioclastic limestone with brachiopods (Bradley et al., 2015). It is equivalent to the Nouatil Gr of the Adrar and Hodh-Afolle subbasins.


Lithology Pattern: 
Clayey Sandstone


Relationships and Distribution

Lower contact

Unconformably overlies the Azlaf Gr

Upper contact

Unconformably overlain by the Erg Cheg Gr

Regional extent

Eastern part of the Taoudeni Basin.


GeoJSON

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Fossils


Age 

Martin-Monge et al. (2016) summary figure schematically indicates a span of Early and Middle Cambrian. Mid-Fortunian (to allow for the Ediacaran/Cambrian hiatus) through Guzhangian is used here

Age Span: 

    Beginning stage: 
Fortunian

    Fraction up in beginning stage: 
0.5

    Beginning date (Ma): 
533.90

    Ending stage: 
Guzhangian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
497.00

Depositional setting

Shallow marine siliciclastic and carbonate depositional environment


Depositional pattern:  


Additional Information


Compiler:  

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

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

Kah, L. C., Bartley, J. K., and Stagner, A. F. (2009): Reinterpreting a Proterozoic enigma: Conophyton-Jacutophyton stromatolites of the Mesoproterozoic Atar Group, Mauritania. International Association of Sedimentologists, Special Publication, 41: pp. 277-295

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