Etel Formation

Etel Fm

Period:

Cretaceous

Age Interval:

upper Turonian

Province:
Sirte Basin

Type Locality and Naming

The lower unit in the Rakb Gr is the Etel Fm.

Synonym (or equivalents elsewhere in basin): Etla Fm (Abdalla et al., 2026), Arguib Fm, Arguib Carbonates (Ahlbrandt, 2001)

References: Selley, 1997; Ahlbrandt, 2001; Abugares, 2007, Abdalla et al., 2026

Lithology and Thickness

The Etel Fm (the Aragub Carbonate is regarded as a basin-ward equivalent of the Etel Fm) consists of thin-bedded carbonates, shale, anhydrite, siltstone and sandstone – with its thickness ranging from 660 m in the Hagfa Trough to over 700 m in the Hameimat Trough. The shale intervals within the Etel Fm are considered to be the principal source rock in the Hameimat Trough.

Lithology Pattern:

Clayey limestone

Relationships and Distribution

Lower contact

It conformably overlies the Lidam Fm (transgressively, hence variable onset)

Upper contact

It is conformably overlain by the Rachmat Fm.

Regional extent

The Etel Formation is widespread across the central and southern part of the Sitt

Basin but is absent on regional highs (Abugares, 2007).

GeoJSON

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Fossils

Foraminifera

Age

Turonian (middle to upper, with the lower Turonian being the upper part of the Lidam Fm)

Age Span:

Beginning stage:

Turonian

Fraction up in beginning stage:

0.3

Beginning date (Ma):

92.55

Ending stage:

Turonian

Fraction up in the ending stage:

1.0

Ending date (Ma):

89.39

Depositional setting

Open marine (Selley, 1997).

Depositional pattern:

Additional Information

Compiler:

T. S. Ahlbrandt (2001): The Sirte Basin Province of Libya—Sirte-Zelten Total Petroleum System, U.S. Geological Survey Bulletin 2202–F

R.C. Selley (1997): The Sirte Basin of Libya. In: African Basins. Sedimentary Basins of the World, 3, edited by R.C. Selley (Series Editor: K.J. Hsu), Elsevier Science B.V., Amsterdam, pp. 27-37.

Abugares, Miloud M. (2007): Deposition, Diagenesis, and Reservoir Development of the Cretaceous Lidam Formation, SE Sirt Basin, Libya. Durham e-Theses. http://etheses.dur.ac.uk/2599/

Elkanouni, I. E. D. (2014). Sedimentology, Sequence stratigraphy and Spatial-temporal Patterns of the late Paleocene Succession, western Sirt Basin, Libya, Durham e Theses. http://etheses.dur.ac.uk/10538/

Abdalla, M, Abdelnabi, A., Zubi, H., Qaysi, S. (2026): Depositional architecture and reservoir quality evaluation of the Early Cretaceous El Abd Sandstone Member: An integrated sedimentologic and diagenetic approach, eastern Sirte Basin, Libya. Jour. Sedimentary Environments, 11:41. https://doi.org/10.1007/s43217-026-00311-7.