Integrated geophysical studies on the area east of Abu Gharadig basin, southern Cairo, Egypt, using potential field data

摘要

Potential field data of the area east of Abu Gharadig basin were used to delineate the tectonic framework of probable economic interest and for future development plans for the area. To achieve this goal, the RTP and Bouguer gravity maps of the study area were subjected to several filtering and processing techniques. The regional magnetic map shows NE–SW high regional magnetic trends at the northwestern and southeastern parts as well as low magnetic trends at the central part reflecting thick non-magnetized sediments and/or deep highly magnetized basement rocks. Similarly, the regional gravity map shows NE–SW diagonal high and low gravity trends across the entire area of study as well as a distinct increase of gravity values toward the northwest corner reflecting thickening of sedimentary cover and/or deepening of denser basement rock at the central part. The residual maps reveal many anomalies of shallow sources with different polarities, amplitudes and extensions in the form of alternating high and low gravity and magnetic indicating that the basement rocks are dissected by faults forming uplifted and downthrown blocks. Edge detection techniques outlined effectively the boarders and extensions of the structural highs and lows through showing gravity and magnetic maxima over the edges of these tectonic features. Moreover, the River Nile course is controlled by shallow normal faults affecting the recent Nile sediments and is clearly shown by edge detection maps of gravity data. Euler deconvolution of magnetic and gravity data reveals clustering of solution along fault trends or causative bodies centers. The Euler depth estimate to the basement surface shows a good correlation with the depth determined by the power spectrum method where its value ranges around 4 km. The interpreted basement tectonic map of the study area is dominated by ENE–WSW Syrian Arc, NW–SE Gulf of Suez and Red Sea, NE–SW Aqaba, E–W Mediterranean and N–S East Africa tectonic trends. The older tectonic trends were reactivated then intersected by younger ones.