Al Hilal Fm
Period:
Cretaceous
Age Interval:
late Santonian
Province:
Cyrenaica Basin
Type Locality and Naming
Synonym:
References: Shaltami, O.R., et al. (2020), and Google Gemina (Aug’26)
Lithology and Thickness
Dark grey-green, organic-rich shales and well-bedded pelagic limestones.
Lithology Pattern:
Pelagic marl
Relationships and Distribution
Lower contact
Unconformable (lower Santonian is absent) onto the Al Baniyah Fm according to Shaltami et al. (2020).
Upper contact
Unconformably overlain by the Al Majahir Fm according to Shaltami et al. (2020).
Regional extent
GeoJSON
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Fossils
Age
Upper Santonian according to Shaltami et al. (2020). [For graphic purposes, the extent of the upper unconformity has been omitted here.]
Age Span:
Beginning stage:
Santonian
Fraction up in beginning stage:
0.5
Beginning date (Ma):
84.68
Ending stage:
Santonian
Fraction up in the ending stage:
1.0
Ending date (Ma):
83.65
Depositional setting
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.