The main phase of lifting the Sirt Basin (Libya) had ceased by the mid-Cretaceous bur Alpine-related tectonic pulses in the late Eocene resulted in northward tilting of the basin. In the Maragh Trough (SE Sirt basin), a regional unconformity consequently separates Eocene carbonates from the overlying Oligocene succession. The unconformity marks a change from Eocene carbonate sedimentation to move mixed shallow-marine deposition in the Oligocene. A regional transgression re-established fully marine conditions in the Miocene. Deeply-buried (Triassic) source rocks in the Maragh Trough reached peak oil generation during the Oligocene. Two potential reservoir intervals have been identified: zipper Eocene rudstones of the Augila Formation, and unconformably-overlying sandstones of the Lower Oligocene Arida Formation. Mid-Oligocene shales provide a regional seal. Facies distributions and reservoir properties are related to rift-related structural highs. Despite the absence of a nearby source kitchen, Upper Eocene carbonates have been found to be oil-bearing in the Maragh Trough at wells D1- and F1-96. This indicates that hydrocarbons have migrated along graben-bounding faults from deeply-buried source rocks to platform and sub-platform areas. Traps are of combined structural and stratigraphic type.