Geological and Structural Setting of Wadi Hodein Area

The Wadi Hodein area in the south Eastern Desert of Egypt is occupied by Neoproterozoic Pan-African (Precambrian) basement rocks including metamorphic and intrusive assemblages. The metamorphic assemblage comprises dismembered ophiolitic metamorphosed ultramafic rocks and island-arc calc-alkaline metavolcanics. On the other hand, the intrusive assemblage rocks include syn-tectonic tonalite-granodiorite (G1) and late-tectonic monzogranites-alkali feldspar granites (G2). These Precambrian basement rocks are unconformably overlain by Cretaceous sandstones and both are extruded by Tertiary basalts. To discriminate the different basement rocks, shear zones, the data of field study together with those of false colour composite ETM ratio image (5/1, 5/7, 5/4*3/4) have been applied and the spectral signature curves of these rocks were delineated. Detailed field mapping and structural studies revealed four events of structural deformation (from oldest to youngest; D1, D2, D3 and D4) affecting the Pan-African basement rocks. D1 is represented by ENE-WSW oriented megascopic upright open folds associated with low angle thrusts as well as mesoscopic tight, overturned and recumbent folds. Kinematic indicators indicate thrusting towards the SSE. D2 is represented by NNW-SSE oriented megascopic and mesoscopic folds, which are tight, verge towards WSW. D3 includes major NNW-SSE trending sinistral shear zones that show subordinate reverse fault component and dip steeply towards the ENE. D4 is represented by NW-SE trending faults and E-W oriented dextral faults with left stepping segments.