El Gassi Formation

El Gassi Fm

Period:

Ordovician

Age Interval:

Tremadocian.

Province:
Oued Mya Basin

Type Locality and Naming

Synonym: Argile d’El Gassi Fm (Klett, 2000).

References: Klett, 2000.

Lithology and Thickness

The El Gassi Fm is mudstone. It overlies a transition (known as the “Zone des Alternances”) from the underlying sandstone (Klett, 2000).

Lithology Pattern:

Claystone

Relationships and Distribution

Lower contact

It conformably overlies the Zone des Alternances Fm; which is a transition upward from the sands of the Massi Messaoud Fm into the overlying mudstone of the Argile d’El Gassi Fm

Upper contact

It is conformably overlain by the Argile d’El Gassi Fm.

Regional extent

GeoJSON

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Fossils

Age

Age Span:

Beginning stage:

Tremadocian

Fraction up in beginning stage:

0.25

Beginning date (Ma):

484.41

Ending stage:

Tremadocian

Fraction up in the ending stage:

0.7

Ending date (Ma):

480.01

Depositional setting

Depositional pattern:

Additional Information

Compiler:

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

Baouche, R., Ganguli, S. S., Sen, S., Radwan A. E. (2023): Assessment of reservoir stress state and its implications for Paleozoic tight oil reservoir development in the Oued Mya Basin, northeastern Algerian Sahara. Geosystems and Geoenvironment 2: pp.1-18. https://doi.org/10.1016/j.geogeo.2022.100112

Fadila B. (2004): Reservoir Characterization and Reservoir Modeling in the Northwestern Part of Hassi Massaoud Field Algeria. A PhD thesis at the University of Hamburg, Hamburg, Germany.

T.R. Klett (2000): Total Petroleum Systems of the Trias/Ghadames Province, Algeria, Tunisia, and Libya - The Tanezzuft-Oued Mya, Tanezzuft-Melrhir, and Tanezzuft-Ghadames. U.S. Geological Survey Bulletin, 2202-C.

Kraouia et al., (2023): Ordovician–Upper Silurian–Triassic Petroleum System Assessment in the Chotts Area. In S. Khomsi and F. Roure (eds.), Geology of North Africa and the Mediterranean: Sedimentary Basins and Georesources, Regional Geology Reviews, https://doi.org/10.1007/978-3-031-18747-6_7