Structural characteristics and tectonic evolution of the northwestern margin of the Nile Delta, Egypt

The Interference between the northeast, East–West, and northwest oriented faults imposed a complex structural setting of the northwestern margin of the Nile Delta, Northeast Africa. The pre-existing faults were reactivated during the evolution of the Nile Delta by two tectonic events. These events took place during the Late Miocene–Early Pliocene and Late Pliocene–Early Pleistocene times and were coeval with two falls in the sea level pattern. Some of these faults have continued to affect the bottom sea sediments and increased the northerly slope of the upper surface of the delta body. The thickness of the Pliocene-Recent sediments and the location of the pre-existing faults controlled these reactivations. The mechanical contrast of these sediments and fault displacements controlled the geometry of the reactivated faults. The rotated displacement on some of these faults is associated with growth units upward. The northwest sinking (bending) of the outer part of the African continental margin under the Eurasian plate at the Hellenic subduction Arc has induced a tangential northwest trending extension (an average of N37°W–S37°E trend) in the outer zone of the northern African margin that is responsible mainly for the reactivations of the pre-existing faults.

► The pre-existing faults controlled the structural architecture and tectonic evolution.
► The sediments thickness and pre-existing faults controlled the fault reactivations.
► The fault slip and lithologic variation controlled the geometry of reactivated faults.
► The fault reactivations and sea level pattern influenced the deposition of delta sediments.
► Bending of the African plate at the Hellenic subduction arc created a northwest extension.