Structural and tectonostratigraphic evolution of Matruh Basin, northern Western Desert, Egypt: An example of an inverted rift basin

Abstract

The Matruh Basin is located in the northwestern part of the Western Desert of Egypt. Being part of the structurally complex northeast African margin, the basin underwent multiple phases of Mesozoic-Cenozoic deformation. Detailed structural analysis of the subsurface structures of this basin, using high-quality 3D seismic and well datasets, has identified two main fault sets: 1) Jurassic- Early Cretaceous (Barremian) NNE-striking normal faults; and 2) Late Cretaceous NW-striking normal faults. The older NNE-striking normal faults were later inverted due to Late Cretaceous compression forming fault-propagation folds (inversion anticlines) in their upper tips. This positive inversion initiated with the “Santonian Event” and continued into the Early Cenozoic. The NW-striking normal faults were not inverted due to their unfavorable orientations.Most inversion structures in the greater Western Desert trend E-W or ENE-WSW and reflect the reactivation of similarly oriented pre-existing normal faults. The NNE orientation of the old, major extensional structures in the Matruh Basin and the resulting control on the later inversion fabric reflects a very different fault architecture. This has dramatically impacted sedimentation patterns and potential hydrocarbon accumulations. The Matruh Basin illustrates the complexities that can be present along the North African Neotethyan margin and underlines the necessity to avoid regional generalizations where gaps in data may be present.