الفهرس 
Chapter IOnly 14 pages are availabe for public view
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Abstract
The study area covers about 3300 km in the Northern part of the Western Desert of Egypt, extending between latitudes 28’ 00’ to 3rJ’ 00 N and longitudes 27’ 00 to 30’ 00 E. This area is considered as a part of the unstable shelf (Mobile) of Egypt. The recent studies on the Northern Western Desert shows that, the rocks and loose sediments cropping out the investigated area belong to the Paleocene, early-middle-late Eocene, Oligocene, early-middle-late Miocene and Quaternary. The lithology of these formations are mainly limestones, sandstones, conglomerates and shales. The subsurface geology of the area under study is clarified from the study of several bore holes. The sedimentary section has different thickness at different parts. The stratigraphic column is generally thick and includes most of the sedimentary succession from Recent to Pre-Cambrian basement complex. The detailed study of the critical analysis of the Bouguer anomaly map in the form of shape, extension, amplitude, type and polarity of its anomalies show that the area is characterized mainly by complex subsurface features in the form of major uplifting and downfaulting blocks on the basement surface and the overlying sedimentary cover, associated with high and low gravity values respectively. The uplifted and downfaulted blocks are separated by linear anomalies of high gradient, great areal extent and different trends. The followinq are the main conclusion that could be derived from the analysis of these linear anomalies a- The predominent directions in the study area are i - 0 N 55 E (Qattara or Syrian Arc trend). 0 N 85 E & N 85 W (Tethyan or Mediterranean or E-W trend)N 250 E ( Aquaba trend ). 0 N 15 W (N-S or East African trend) .N 450 W ( Suez trend ) .
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b- These recorded tectonic trends represent the most predominent directions in Egypt as recorded by Youssef, 1968. Qattara and E-W trends are most probably the oldest tectonics in the area, which also control the basement block moasic of the Western Desert of Egypt (Halsey et.al., 1975). It is thought that the E-W trend was developed mainly due to compressional fold thrust directions related to late Tertiary, (N-S compression), youssef, 1968 and Halsey et.al., 1975. The Qattara trend has much more manifistation on the sedimentary cover and it is the principal controling direction of major folding running across Egypt from Libya to the Dead sea Rift (Said, 1962 and Halsey et.al., 1975). The Qattara, E-W and the Suez trends represents the most important tectonic directions that affected the structural development of the study area. c- Two sets of shear zones were detected in the study area. The first include four right lateral shear zones striking in NW direction, whereas the other set include thirteen lift lateral zones striking in NE direction. The NW trending set may represent the Suez right lateral shearing clained to be existing by Halsey et. al., 1975, Health, 1975, and Riad, 1977. Also, El-Shazlyet.al., 1975, reported that faults of NW-SE direction may be strike slip faults of right-lateral type. Whereas the NE trending set, most probably includes the Aqaba shear direction which constitutes, together with the Suez trend, the conjugate shear components resulting from the N-S compression. d- The number, mean depths to the upper and lower surfaces of the different faults show that the predominant range of the basement depth was found to be ranging from 0.5 to 5.0 kms. In the study area. e- The density contrast between the basement rocks and the overlying sedimentary rocks was found to be 0.23 gm/cm. f- Some statistical tests such as, product moment correlation coefficient (Karl Pearson), the Standared Deviation (S.D.) and Rank order Correlation Coefficient (Spearman), were used in the present study to deduce a probable relationships between the fault parameters. The results of this study shows a good linear relation between the length of the faults and their different parameters (upper and lower depths and the downthrow of the faults).