A general agreement is established that rifting of the Red Sea since the Oligocene and younger times led to uplifting and exhumation of the Neoproterozoic Arabian–Nubian Shield (ANS). The ANS comprises a college of tectonic terranes separated along ophiolites-decorated maga shears, and is regarded to represent the northern extension of the East African Orogen (EAO). The ANS experienced final accretion to the Saharan Metacraton in the west concurrent with Gondwana assembly through progressive oblique convergence of East- and West-Gondwanalands. The Eastern Desert Terrane (EDT), the northwestern part of the ANS, has experienced a polyphase deformation history involving three successive episodes (D1, D2 and D3), where folding, thrusting and shearing are geometrically- and kinematically- related. In this study, these episodes and related geometric and kinematic relationships are envisaged for a clear understand of the evolution of this part of the ANS. In the Southern EDT, fold-thrust belts prevail and thrusts are first-order kinematic later overprinted by map-scale transpression. Fold-related faults are dominant in the central EDT, and are commonly associated with pull-apart basins linked to Najd System. In the northern EDT, faults and joint systems are dominant, and thrusts where observed are attenuated as most of the sector is masked by younger granitoid intrusions. The major structures in the south are manifested by accretion-induced sutures developed at ca. 750-720 Ma, while pull apart basins in the central sector of the EDT are related to the 640-580 Ma Najd System. Brittle deformation in the northern sector is evidently late. The nature and overprinting relationships between the pervasive structures at all scales in the EDT point towards structural younging towards the north, approaching the peripheries of the EDT. We assume that juvenile crust was formed in the rifted zones and surrounding the ANS and the EDT is a good example. |
