Zone des Alternances Formation

Zone des Alternances Fm

Period:

Ordovician

Age Interval:

Tremadocian.

Province:
Oued Mya Basin

Type Locality and Naming

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

References: Klett, 2000.

Lithology and Thickness

The Zone des Alternances Fm is characterized by clayey sandstone that grade upwards into sandy mudstones (Klett, 2000).

Lithology Pattern:

Clayey sandstone

Relationships and Distribution

Lower contact

It conformably overlies the sandstone of the Hassi Messaoud Fm.

Upper contact

It is conformably overlain by the claystone of the Gres d’El Atchane Fm.

Regional extent

GeoJSON

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Fossils

Age

Age Span:

Beginning stage:

Tremadocian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

486.85

Ending stage:

Tremadocian

Fraction up in the ending stage:

0.25

Ending date (Ma):

484.41

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