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Glebet et Atores Formation
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Glebet et Atores Fm base reconstruction

Glebet et Atores Fm

Period: 
Calymmian

Age Interval: 
Late Calymmian


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 Glebet el Atores Formation is approximately 80 m thick at Chegga and consists of basal conglomerates resting unconformably on basement, passing upward into fine grained sandstones with stromatolite-bearing carbonate lenses, and then into aeolian sandstones (Taylor and Giles, 2013). It is equivalent to the Agueni Fm of the Char Gr of the Adrar Subbasin.


Lithology Pattern: 
Coarse-grained sandstone


Relationships and Distribution

Lower contact

Non-conformably overlying the Basement Complex

Upper contact

Conformably underlies the Chegga Fm (Martin-Monge et al., 2016)

Regional extent

Eastern part of the Taoudeni Basin.


GeoJSON

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Fossils


Age 

See Hohd Super Gr entry for discussion of age assignments to Neoproterozoic units. The legend to the USGS regional map (Bradley et al., 2015) indicates that the onset of the lowest units begins shortly after 1600 Ma. Temporarily, the onset is arbitrarily set here as 1500 Ma (mid-Calymmian); with the Douik Gr (and regional equivalents) arbitrarily placed as upper Calymmian through lower Ectasian (1500 to 1300 Ma), then the major regional "D2" regional unconformity. Formations within the Douik Gr are scaled following their relative proportions in the stratigraphic figure from Martin-Monge et al. (2016)

Age Span: 

    Beginning stage: 
Calymmian

    Fraction up in beginning stage: 
0.5

    Beginning date (Ma): 
1,500.00

    Ending stage: 
Calymmian

    Fraction up in the ending stage: 
0.85

    Ending date (Ma):  
1,430.00

Depositional setting

Continental/Aeolian (Taylor and Giles, 2013)


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