Damergou Gr

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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Damergou Gr

Period:

Cretaceous

Age Interval:

Late Cretaceous (Late Cenomanian to Santonian) (4)

Province:
Iullemmeden Basin - Southeast Aïr & Damergou

Type Locality and Naming

Damergou (no accurate location). Joulia, 1953.

References: Furon, 1934; Joleaud et al., 1935(?); Joulia, 1953; Faure, 1966, p. 159; Fabre et al., 1983; Moody et al., 1991; Mathey et al., 1991.

Synonym: There is a possibility that the “Série crétacée de Tanout” of Joleaud et al. (1935) be equivalent to the Damergou group.

Lithology and Thickness

Its thickness is 179 m. Deposits including, from top to bottom (see each formation individually) (Fig. 1):

Lower portion of the Dambanza Fm: flaky clays; at the base, a horizon of limestone with lamellibranchs;
Gangara Fm: calcareous clays (vertebrates, fish) and fine sandstones;
Béréré Fm:
clays containing two calcareous ammonite levels,
Sandstone with clay layers.

[Figure 1: Lithostratigraphy of the Damergou Gr displaying its formations (Béréré Fm to lower portion of the Dambanza Fm) (Source: Modified from Faure, 1966, p. 158)]

Lithology Pattern:

Sandy claystone

Relationships and Distribution

Lower contact

Underlying unit is the Farak Fm

Upper contact

Overlying unit is the Upper portion of the Dambanza Fm. (NOTE: the lower portion of Dambanza Fm is in this Damergou Gr, which is confusing!)

Regional extent

Iullemmeden Basin - Southeast Aïr & Damergou

GeoJSON

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Fossils

Vertebrates and fish in the Lower Gangara Fm.

Age

Late Cretaceous (Late Cenomanian to Santonian)

Age Span:

Beginning stage:

Cenomanian

Fraction up in beginning stage:

0.5

Beginning date (Ma):

97.20

Ending stage:

Santonian

Fraction up in the ending stage:

1.0

Ending date (Ma):

83.65

Depositional setting

Marine and Continental

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)