Home Multi-Country Search About Admin Login


Information provided by geoscience team at Ahmadu Bello University, Zaria, Nigeria --see About

Search by
Select Region(s) to search
Hold Ctrl (Windows/Linux) or Command (Mac) to select multiple
Oued Chig Gr
Click to display on map of the Ancient World at:
Oued Chig Gr base reconstruction

Oued Chig Gr

Period: 
Silurian

Age Interval: 
Rhuddanian –Ludfordian


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 Oued Chig Group is made up entirely of Black Shale. The group can be found in the Hodh-Afolle Subbasin, with its equivalent in the Hank Subbasin called Toba El Hamar.


Lithology Pattern: 
Claystone


Relationships and Distribution

Lower contact

Conformably overlies the Tichit Gr

Upper contact

Unconformably overlain by the Tenemouj Gr

Regional extent

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


GeoJSON

{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[-8.51,23],[-8.51,20.35],[-7.46,19.1],[-4.81,17.65],[-4.41,17.05],[-5.06,14.65],[-5.46,12.65],[-6.01,11.29],[-7.56,12.4],[-9.76,12.25],[-10.76,12.05],[-11.77,14.25],[-12.27,17.55],[-13.37,19.5],[-13.22,21.45],[-12.32,22.95],[-11.72,23.3],[-10.41,22.6],[-8.51,23]]]]}}

Fossils


Age 

Martin-Monge et al. (2016) summary figure schematically indicates a span of nearly the entire Silurian; but an arbitrary allowance is made here for a hiatus at the Silurian-Devonian boundary (hence Pridoli as an arbitrary gap).

Age Span: 

    Beginning stage: 
Rhuddanian

    Fraction up in beginning stage: 
0.00

    Beginning date (Ma): 
443.07

    Ending stage: 
Pridoli

    Fraction up in the ending stage: 
0.0

    Ending date (Ma):  
422.73

Depositional setting

Marine transgressive deposits after the Hirnantian glacial lowstand (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