Cenozoic

Cretaceous

Jurassic

Triassic

Permian

Paleozoic

Compiled by: Jacques LeBlanc (2022), Stratigraphic Lexicon: The Sedimentary Formations of The Republic of Niger, Africa. Colnes Publishing (Tallin, Estonia), 365 pp. For more information see "About"

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Madaouela Formation

Madaouela Fm

Period:

Permian

Age Interval:

Early Permian (Kungurian) to possibly(?) early Middle Permian (Roadian) (1)

Province:
Iullemmeden Basin - Tim Mersoï Sub-basin

Type Locality and Naming

Group/Subgroup: Upper Tagora Gr

References: Claret & Tempère, 1968; Abdoul Aziz, 1968; Fabre et al., 1983; Broutin et al., 1990; Coquel et al., 1995; Fabre, 2005; Billon et al. 2016; CSA Global, 2017, 2019; Alfidja et al., 2021.

Synonym: Madaouella; Madaougla; Madawela; former upper Member of the Tarat Fm. “Argilo-gréseux de Madaouela”.

Lithology and Thickness

Argillites with intercalations of fine calcareous sandstones, coarse micro-conglomeratic sandstones and siltstones. Uranium mineralization is associated with sandstones. The formation does not outcrop, at least not obviously, and can be confused when the arkoses of the Izégouande Fm cover it unconformably. Can be thicker than 350 m thick.

Lithology Pattern:

Sandy claystone

Relationships and Distribution

Lower contact

In discordance with the underlying Tarat Fm.

Upper contact

The top can be reddish under the overlying Arlit Fm.

Regional extent

It is not always present. It is known only to the west of the Arlit-In-Azaoua (AIA) major fault and south of the Madaouela fault (Figure).

[Figure. Northwest-southeast profile of the Tim Mersoï Sub-Basin in the Arlit area. Section A-B above (Source: Modified after CSA Global, 2019).]

GeoJSON

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Fossils

Rich in plant fragments. Yielded Lepidodendrons, brachiopods and polypiers.

Age

It has long been assumed to be of Upper Carboniferous (Pennsylvanian) age, however, Broutin et al. (1990) have established an Early Permian age (equivalent to the Kungurian of the Global Stages) to possibly(?) early Middle Permian (Roadian) for the upper portion of the Tarat Fm (now the Madaouela Fm) based on palynological data. (See Tarat Fm). This has also been confirmed by Coquel et al. (1995).

Age Span:

Beginning stage:

Kungurian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

283.30

Ending stage:

Roadian

Fraction up in the ending stage:

1.0

Ending date (Ma):

269.21

Depositional setting

Fluvial sandstone. The whole unit is Estuarine, Fluvial to marine.

Depositional pattern:

Additional Information

Compiler:

Jacques LeBlanc (2022), Stratigraphic Lexicon: The Sedimentary Formations of The Republic of Niger, Africa. Colnes Publishing (Tallin, Estonia), 365 pp. https://doi.org/10.47909/978-9916-9760-6-7 (or via https://sites.google.com/site/leblancjacques)