Title : The tectonostratigraphic evolution of the Atshan-Gargaf Arch,and its influence upon flanking petroleum systems, Western Libya
Abstract:
The Gargaf-Atshan Arch, located in Western Libya, is a significant structural feature that separates the Ghadamis and Murzuq Basins. A Virtual Field Trip Guide is being developed to highlight key outcrop sections along this Arch and serve as a teaching tool, demonstrating the dynamic relationship between its tectonic history and entrapment of oil and gas in fields nearby.
The arch has undergone multiple exhumation events, which culminated in recent uplift and erosion, revealing a range of geological formations from the Lower Palaeozoic to Miocene epochs. Detailed tectono-stratigraphic studies based on well correlations and outcrop sections have identified the lateral extent of key unconformities and quantified the amount of erosional unroofing. These exhumation events have had a profound impact on petroleum systems around the arch, influencing the distribution of reservoirs, source maturation, expulsion, and charge. The petroleum reservoirs in the region, primarily located in Ordovician (Hawaz and Memouniat Formations) and Devonian (Tadrart Formation and F3 Unit) sandstones, are charged by the organic-rich radioactive shales of the Lower Silurian Rhuddanian age, known as the Tanezzuft ‘hot’ Shale. Maximum burial, peak expulsion and charge appears to have occurred immediately prior to mid-Cretaceous unroofing in most of the nearby fields with evidence locally of freshwater flushing during later Cenozoic exhumation of the Arch
Key Words: Gargaf-Atshan Arch, exhumation events, Virtual Field Trip Guide
