الفهرس 
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Abstract
The Ghadames Basin of NW Libya contains more than 10 billion barrels oil-equivalent in Palaeozoic siliciclastic reservoirs which are charged by organic-rich “hot shales” in the Lower Silurian (Rhuddanian) Tanezzuft Formation. Geochemical analysis of 85 shale samples and ten oils from three Concessions (NC2, NC4 and NC7) in the central and northern part of the basin provides a robust description of the Tanezzuft – Mamuniyat/Acacus petroleum system in this region, and of the associated source facies and oil familiesTwo palynofacies associations are recognized and described: in ascending order these are: Hot Shale Palynofacies: distal suboxic–anoxic environment, with Type-II≥I kerogen (highly oil-prone). The Tanezzuft Formation Palynofacies: distal suboxic–anoxic basin to mud-dominated oxic shelf (distal shelf) with Type-II/III kerogen (oil- and gas-prone. The age assignment is based mainly on acritarchs. Accordingly, the Hot Shale is dated as Early Silurian, early–mid Rhuddanian (early Llandovery) whereas the rest of the Tanezzuft Formation is late Rhuddanian–Telychian (Llandovery).The analysed oils are characterised by low sulphur, nickel and vanadium contents, and relatively high API gravity (34.9–46.8oAPI). Biomarkers suggest that they were generated from marine shales containing abundant Type II to mixed Type II/III kerogen deposited in mildly anoxic – suboxic conditions with a dominance of C29 over C27 or C28 steranes, indicative of a source rich in brown algae and cyanobacteria. Their close stratigraphic association and biomarker characteristics support a Tanezzuft “hot shales” source for the Mamuniyat and Acacus oils in the three concessions. The NC7 Concession are significantly more mature than those from the NC2 and NC4 concessions. This indicates a difference in expulsion timing and may be related to the two “hot shales” or to fault-triggered vertical migration preceding and during the Neogene.