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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Ezerza Formation

Ezerza Fm

Period:

Cretaceous

Age Interval:

Upper Cretaceous (Lower Cenomanian) (7c, 8a)

Province:
East Niger Rift Basin - Bilma Sub-basin, East Niger Rift Basin - Termit Sub-basin

Type Locality and Naming

Faure, 1959b

References: Faure, 1959b, 1966; Fabre et al., 1983; Meister et al., 1994; Konaté et al., 2019.

Equivalent(s): Alanlara Fm ; Cheffadène Fm ; Ezerza-Cheffadène Fm

Lithology and Thickness

This formation is characterized by soft levels (green shales, etc.), where beds of siltstones and black limestone are frequent. The limestones are almost always in very thin layers and are loaded with silts. The beds of fibrous black calcite, with a "beef" structure, are numerous and come from the recrystallization of the calcite from the immediately neighboring calcareous layers. These facies are identical to those examined in the Alanlara Fm in Téfidet Sub-Basin. Thickness is 200 m

Lithology Pattern:

Continental marl

Relationships and Distribution

Lower contact

Underlying unit is the Achegour Fm (Bilma Sub-basin) or the Dibella Fm (Termit – East)

Upper contact

Overlying Unit is the Ammonite limestones of the Zoo Baba Fm

Regional extent

East Niger Rift Basin - Bilma & Termit East

GeoJSON

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Fossils

Beds of phosphatic conglomerate with fishbone debris are characteristic of the Ezerza Fm. Sometimes, in rolled fragments the bones reach 0.5 cm and are embedded in a calcareous siltstone cement. Rare bivalves are also present.

Age

Upper Cretaceous (Lower Cenomanian)

Age Span:

Beginning stage:

Cenomanian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

100.50

Ending stage:

Cenomanian

Fraction up in the ending stage:

0.5

Ending date (Ma):

97.20

Depositional setting

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)