Structural and Tectonic Subsidence History Study of Southwestern Sirt Basin, Libya

The study area is the south most of the western part of the Sirt Basin. Seismic and gravity data have been used to delineate the local structures within the area of study and to investigate their lateral and vertical extension. The area is located nearby Al-Harouge basaltic mountain which associated with a number of ingenious intrusions. The seismic data show that the area dominated by a group of differentiated fault zones caused the common characteristics of the area. The majority of these faults are trending NW-SE coincidences with the general tectonic elements of the basin, and extremely controlled the strata thickness and formed a number of deep sub-troughs. Group of wells was used to study the tectonic history of the area the analysis shows that the area passed with four main tectonic stages, the first stage was the initial rift phase, started proximately at the Mid-Cretaceous time ~100Ma during which the area underwent a significant amount of subsidence, the second stage began at the ~84Ma and characterized by a slow post-rift subsidence persisted until the second rift phase initiated during which a rapid syn-rift subsidence took place and continued through the PaleoceneEocene time. At about 40Ma the second post-rift subsidence was begun and persisted to the present day.