Al Athrun Fm
Period:
Cretaceous
Age Interval:
early Maastrichtian
Province:
Cyrenaica Basin
Type Locality and Naming
Synonym:
References: Shaltami, O.R., et al. (2020), and Google Gemina (Aug’26)
Lithology and Thickness
Deep marine, highly fossiliferous pelagic chalky limestones featuring frequent chert bands.
Lithology Pattern:
Chalk
Relationships and Distribution
Lower contact
Unconformable onto the Al Majahir Fm according to Shaltami et al. (2020).
Upper contact
Unconformably overlain by the Wadi Dukhan Fm according to Shaltami et al. (2020).
Regional extent
GeoJSON
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Fossils
Age
Early Maastrichtian according to Shaltami et al. (2020). [For graphic purposes, the extent of the upper and lower unconformities, which are equivalent to nearly the same time span of the known preserved deposits, have been omitted here.]
Age Span:
Beginning stage:
Maastrichtian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
72.17
Ending stage:
Maastrichtian
Fraction up in the ending stage:
0.5
Ending date (Ma):
69.11
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.