![]() | Only 14 pages are availabe for public view |
Abstract The northernmost of the Neoproterozoic Arabian-Nubian Shield (ANS) comprises a volcano-sedimentary metamorphic complexes evolved during the Pan African Orogeny. While these ”complexes” are well entrenched as separate regions of metamorphic rocks in the literature, the distinction among them is largely based on the fact that they are located in different areas (some tens of kilometres apart) and are separated by extensive regions of post-tectonic granitoids. Here we propose that their relationship may be understood within the same framework of Pan-African tectonics as known for the Eastern Desert of Egypt. Because of the separation of the metamorphic complexes by expansive areas of undeformed granitoids, the relationship among the different metamorphic regions is not as straight forward to understand as it is in the Eastern Desert of Egypt. In this thesis we try to understand the relationship among the metamorphic complexes in south Sinai by comparing their structural characteristics and metamorphic grade. The present study reveals that the south Sinai metamorphic complexes were subjected to four deformational events, the earliest tectonic event, D. is differing in the high grade of metamorphism Feiran-Solaf metamorphic complex (FSMC) from the low grade of metamorphism of the Sa’al-Zaghra metamorphic complex (SZMC) and the Kid metamorphic complex (KMC), in which FSMC is expressed by extensional tectonic regime and compressional regime for SZMC and KMC. The second deformational event D2 related to a contractional regime of thrust related shear zones and its associated thrust faults. This deformation is related to the major collision and accretion between East and West Gondwana. The third tectonic event D3 represents oblique sinistral NW-SE transpressional regime associated with NW-SE sinistral shear sense indicators and NE-SW dextral shear sense indicators. This event is known to have formed the Najd Fault System equivalent to the same deformation in the Eastern Desert as a result of the collision of East and West Gondwana. The last tectonic event D4 during the Pan African Orogeny reveals change in the stress regime form shortening NE-SW to shortening NW-SE and WNW-ESE revealing open concentric folds trending NE-SW to NNE-SSW followed by extension NW-SE associated with the intrusion the NE-SW alkaline suite bodies. The later tectonic events represents dextral NW -SE system of shear zones probably represents reactivation of the NFS during the Oligo-Miocene. |