Abstract
Infracambrian sediments are widely distributed in Libya, outcropping on the eastern and western margins of Al Kufrah Basin and the eastern margin of Murzuq Basin. The sediments have been penetrated in the Central Cyrenaica Platform, Concession 10, NW Sirte Basin, and Block NC115, NW Murzuq Basin.
There are two main subdivisions. The first is metamorphosed due to local volcanism in the Murzuq and Al Kufrah basins. The second is unaltered and has been penetrated in the NW Sirte Basin. It occurs as outcropping limestone on the eastern margin of the Murzuq Basin.
These sediments generally show lateral thickness variability, with the thickest section, approximately 991-1067 m, in the Cyrenaica Platform. Individual units show thinning towards the Precambrian basement highs, and both fining-up and coarsening-up successions. Two-dimensional seismic data acquired by the operating companies AGIP and AGOCO in the southern Al Kufrah Basin image strata presumed to be Infracambrian.
The Infracambrian sediments were probably deposited as lens-shaped bodies in palaeo-lows (graben, half-graben and troughs) alongside Precambrian basement highs, trending NW-SE in the Cyrenaica platform and NE-SW in the Al Kufrah and Murzuq basins. These sediments show lateral facies changes and their nomenclature differs across the basins. Palynological and palaeontological studies suggest a Late Riphean age.