Lidam Formation

Lidam Fm

Period:

Cretaceous

Age Interval:

upper Cenomanian-lower Turonian

Province:
Sirte Basin

Type Locality and Naming

The name (Lidam) was proposed for the formation by Barr and Weegar (1972), and was first applied to subsurface units in various parts of the Sirt Basin (Abugares, 2007).

Synonym:

References: Weegar, 1972; Selley, 1997; Abugares, 2007

Lithology and Thickness

The Lidam Formation contains glauconite, phosphate and a diverse and locally abundant assemblage of marine fossils. It is made up of thinly interbedded sands, shales, limestones, dolomites with nodular anhydrite (Selley, 1997).

Lithology Pattern:

Sandy limestone

Relationships and Distribution

Lower contact

It transgressively overlies the Bahi Fm.

Upper contact

It is transgressively overlain by the Etel Fm of the Rakb Gr.

Regional extent

GeoJSON

{"type":"Feature","geometry":{"type":"Polygon","coordinates":[[[14.072,32.722],[14.515,33.633],[16.829,34.889],[17.001,34.52],[16.78,34.347],[17.248,33.608],[17.001,33.288],[17.248,33.017],[18.528,32.771],[20.079,33.165],[21.285,29.914],[23.673,29.741],[24.264,29.594],[24.51,29.199],[23.255,27.845],[22.639,25.776],[20.694,24.52],[19.759,24.52],[19.463,24.249],[19.168,24.446],[18.872,23.953],[16.854,23.436],[16.509,24.101],[17.248,25.283],[17.986,25.53],[18.331,27.549],[17.691,28.19],[16.509,28.239],[16.189,28.51],[14.835,30.924],[15.303,31.145],[15.352,31.441],[14.072,32.722]]]}}

Fossils

Age

upper Cenomanian-lower Turonian

Age Span:

Beginning stage:

Cenomanian

Fraction up in beginning stage:

0.7

Beginning date (Ma):

95.88

Ending stage:

Turonian

Fraction up in the ending stage:

0.3

Ending date (Ma):

92.55

Depositional setting

The Lidam Formation is considered the first marine transgressive unit in the Sirte Basin.

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.