TAGI Formation

TAGI Fm

Period:

Triassic

Age Interval:

Carnian (?).

Province:
Oued Mya Basin, Ghadames Basin

Type Locality and Naming

TAGI = Triassic Argilo-Greseux Inferieur Fm = Triassic Clayey Sandstone Lower (informal term based on facies),

Synonym: Nezla Fm, Triassic Argilo-Greseux Inferieur Fm (Klett, 2000). Ghadames Basin? – diagram in Bora and Dubey, 2015)

References: Klett, 2000; Kraouia et al., 2023.

Lithology and Thickness

The Argilo-Greseux Inferieur Fm is made up of Sandstones, mudstone, salt, and volcanic rocks (Klett, 2000). In the Chotts Basin, the TAGI Fm. is made up of massive sandstone with minor claystone intercalations. The formation is sometimes found below the volcanic body, sometimes above and is sometimes completely absent. In the Chotts region, well reports suggest that the reservoir is being sandwiched by volcanic material, occurring above and below (Kraouia et al., 2023).

Lithology Pattern:

Sandy claystone

Relationships and Distribution

Lower contact

It unconformably overlies the Tiguentourine Fm in the Oued Mya Basin, while it unconformably overlies the Zoumit Fm in the Chotts Basin. The Permian through Middle Triassic is absent.

Upper contact

It is conformably overlain by the Argilo-Carbonates Fm. in the Oued Mya Basin, and it is conformably overlain by the Azizia Fm in the Chotts Basin.

Regional extent

Ghadames Basin and Oued Mya (or Triassic) Basin (Klett, 2000) and Chott Basin.

[Chott Basin not included in this GeoJSON, pending verification in that Chott column.]

GeoJSON

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Fossils

Age

Age Span:

Beginning stage:

Carnian

Fraction up in beginning stage:

0.00

Beginning date (Ma):

237.00

Ending stage:

Carnian

Fraction up in the ending stage:

0.5

Ending date (Ma):

232.15

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

Bora, D., Dubey, S. (2015): New insight on petroleum system modeling of Ghadames basin, Libya. Journal of African Earth Sciences, 112: pp.111-128. http://dx.doi.org/10.1016/j.jafrearsci.2015.08.020