Mamuniyat Formation

Mamuniyat Fm

Period:

Ordovician

Age Interval:

Hirnantian

Province:
Murzuq Basin, Ghadames Basin, Al Kufrah Basin

Type Locality and Naming

NC 115 license area; It was first described by Massa and Collomb (1960) from the western part of Jabal AI Hasawnah in the vicinity of Mamuniyat (Mamuniyat province), after which it has been named.

Synonym: Memouniat Fm (Craig, 2006; used in SEPM summary)

References: Mamgian, 1980; Massa and Collomb, 1960; Collomb, 1962; Grubic et al., 1991; Aziz, 2000; Davidson et al., 2000; Fello, 2001

Lithology and Thickness

It generally comprises massive, cross-bedded, and fine to coarse-grained to conglomeratic sandstones, with siliceous and sometimes mixed cements. The thickness of the Mamuniyat Formation is highly variable (Aziz, 2000). The subsurface occurrence of the Mamuniyat Formation is widespread, with thicknesses in the range 20-170m, but with a regional thickening towards the Al Qarqaf high (Alkhalas, 2006).

It consists of thick-bedded to massive, less frequently thin-bedded quartz sandstones, mainly whitish-grey, yellowish or pink in colour (Grubic et al., 1991).

The Mamuniyat Formation can be subdivided into Upper, Middle and Lower members, based on textural properties, sedimentological characteristics and sequence stratigraphic analysis (Fello, 2001).

Lithology Pattern:

Coarse-grained sandstone

Relationships and Distribution

Lower contact

It unconformably overlies the Melez Shuqran Fm (Ordovician glaciation).

Upper contact

It is unconformably overlain by the Tanezzuft Fm in the Murzuq and Al Kufrah Basins, while it is conformably overlain by the Bir Tlacsin Fm. in the Ghadames Basin.

Regional extent

It is present in both the Murzuq, Ghadames, and Al Kufrah Basins.

GeoJSON

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Fossils

Age

Age Span:

Beginning stage:

Sandbian

Fraction up in beginning stage:

0.00

Beginning date (Ma):

458.18

Ending stage:

Katian

Fraction up in the ending stage:

1.0

Ending date (Ma):

445.21

Depositional setting

The Mamuniyat Formation represents the second glacial-marine cycle of the Paleozoic in Murzuq. A periglacial depositional setting is interpreted based on ecological grounds (Pierobon, 1991).

Depositional pattern:

Additional Information

Compiler:

Enam O. Obiosio, Solomon Joshua Avong and Henry Nasir Suleiman (2024) - Stratigraphic Lexicon compiled from the following books: