الفهرس 
Introduction and regional geological settingOnly 14 pages are availabe for public view
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Abstract
The present study deals with the structural characteristics and tectonic evolution of the Sinai hinge zone in northeastern Sinai and its relationship to the surrounding major structural elements. The Sinai hinge zone is a narrow structural zone that extends from El Giddi and Mitla Passes in westcentral Sinai to the Dead Sea transform. This zone includes two subparallel, closely spaced structural belts in the study area; namely the northern and southern structural belts. These two belts are oriented EW and ENEWSW and mark the boundary between a southern tectonically stable and relatively intact continental crustal block and a northern tectonically unstable crustal block. Each structural belt consists of a number of ENEoriented, rightstepped en echelon fault segments that controlled the development of the different structures in the mapped area. The Sinai hinge zone inherited its ENEWSW orientation from preexisiting normal faults of Precambrian age. The distance between the northern and southern structural belts of the Sinai hinge zone decreases from west to east leading to an increase in the intensity of deformation from west to east. The fault segments of this hinge zone affect exposed sedimentary rocks ranging in age from Triassic to Middle Eocene. Folds play also a major role in the structural deformation of the study area and are NEto ENEoriented asymmetrical, plunging or doubly plunging folds of intermediate size. Secondorder wrench structures were formed contemporaneously with the ENE oriented en echelon fault segments of the hinge zone and include NE to ENEoriented, rightstepped en echelon, plunging or doubly plunging folds; WNWoriented, leftstepped en echelon, rightlateral strikeslip faults (Riedel, Rshears); NNW to NNE oriented, leftlateral strikeslip faults (conjugate Riedel, R/shears) and NW oriented normal faults. These structures indicate that the study area was affected by a dextral shear couple. The ENE oriented fault segments are associated by NE and/or SW plunging folds which make acute angles with them. Several areas between the ends of the ENEoriented en echelon, rightlateral, strikeslip fault segments of the two structural belts were either extended by pullapart grabens or shortened by pushup structures and ?half domes?. The style of Late CretaceousEarly Tertiary structural rejuvenation of the EENE oriented faults of the Early Mesozoic passive continental margin of the Neotethys proceeded via simpleparallel wrenching in the Sinai hinge zone and is related to the oblique convergence between the AfroArabian and Eurasian plates during the closure of the Neotethys. NWSE shortening direction related to the oblique convergence between the two major plates deformed the blocks lying between the structural belts through the development of NESW to ENEWSW oriented folds and reverse faults, at acute angles to the structural belts of the Sinai hinge zone. The mapped portion of the Sinai hinge zone shows structural rejuvenation of early Mesozoic (JurassicEarly Cretaceous) ENEoriented deepseated normal faults in the Late CampanianEarly Maastrichtian (mostly Late Cretaceous), postMiddle Eocenepre Early Miocene and postEarly Miocene times. Four major phases of structural deformation affected the whole region of the Sinai hinge zone, the earliest of which (D1, JurassicEarly Cretaceous rifting) was associated with the drifting of the AfroArabian plate away from the Eurasian plate during the opening of the Neotethys and the formation of EENE oriented rift basins and half grabens in the whole region of northern Egypt. Late CretaceousEarly Tertiary phase of deformation (D2) was associated with Syrian arc folding related to the oblique convergence between AfricanArabian and Eurasian plates due to the closure of the Neotethys. PostMiddle EocenepreEarly Miocene phase of deformation (D3) affected the Sinai hinge zone and Themed fault by dextral wrenching. It is probably related to the late stages of Syrian arc deformation due to the continued closure of the Eastern Mediterranean basin. PostEarly Miocene deformation (D4) affected the basaltic igneous dike of Gebel Rishat Lehman along the Sinai hinge zone due to the dextral wrenching on the ENE oriented Gebel Rishat Lehman fault segment. The occurrence of a few sporadic earthquakes on the central SinaiNaqb shear zone indicates that this fault zone is still seismically active