Al Faidiyah Fm
Period:
Neogene
Age Interval:
Aquitanian
Province:
Cyrenaica Basin
Type Locality and Naming
Synonym:
References: Shaltami, O.R., et al. (2020), and Google Gemina (Aug’26)
Lithology and Thickness
Predominately shale (chart of El Oshebi and Fares, 2026). Google Gemini overview “Basal Unit: The bottom of the formation is typically marked by a distinctive green, glauconite-rich claystone to marl bed. In some areas (like Umm Ar Razam), these basal claystones contain bentonite formed from altered volcanic ash. Upper Unit: The lower clays grade upward into alternating beds of fossiliferous marly limestones, chalky bioclastic limestones, and thin greenish shales.”
Lithology Pattern:
Claystone
Relationships and Distribution
Lower contact
Unconformable onto the Qasr Al Balatah Fm of the Al Abraq Gr according to Shaltami et al. (2020).
Upper contact
Unconformably (upper Aquitanian is absent) overlain by the Jardinah Fm of the Ar Rajmah Gr according to Shaltami et al. (2020).
Regional extent
GeoJSON
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Fossils
“Highly fossiliferous, packed with large benthic foraminifera (Operculina, Lepidocyclina, and reworked Nummulites), bryozoans, echinoids, and bivalves (notably Pecten and oysters).” (Google Gemini overview)
Age
Aquitanian according to Shaltami et al. (2020). [For graphic purposes, the extent of the upper and lower unconformities, which exceed the time span of the known preserved deposits, have been omitted here, but are included in the stratigraphic column in the user-interface.]
Age Span:
Beginning stage:
Aquitanian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
23.04
Ending stage:
Aquitanian
Fraction up in the ending stage:
1.0
Ending date (Ma):
20.45
Depositional setting
“Records a widespread transgressive marine event across a shallow to mid-outer shelf platform environment. Its basal unconformity and transgressive glauconitic layer record major tectonic reorganizations and sea-level shifts along the North African margin during the Oligo-Miocene transition.” (Google Gemini overview)
Depositional pattern:
Additional Information
:
Compiler:
s:Shaltami, O.R., et al. (2020). Petroleum system of the Cyrenaica Basin – A review. In: 1st International Symposium on Geosciences (ISG2020), 21th March 2020, Proceeding Book: published by BR Petrobras. P. 64-71.Tawadros, E.E. (2011). Geology of North Africa. CRC Press (Taylor & Francis Group), 931 pp.Google Gemini (Aug 2026) – assembled synthesis of Cyrenaica Basin units from various web-accessible publications.
El Oshebi, F.M., Fares, F.F. (2026). Stratigraphy, facies, and depositional environments of the Eocene sequence in the Ras Al Hilal area, Cyrenaica, Libya. Arabian Jour. Geosciences, 19:79. https://doi.org/10.1007/s12517-026-12488-2.
El-Hawat, A.S., Abdulsamad, E.O. (2004) Geology and Archeology of Cyrenaica, Northeastern Libya. Field trip guide B01, 32nd International Geological Congress. 36 pp.