SHAPING BURIED BEDROCK TOPOGRAPHY USING RESISTIVITY AND GRAVITY DATA IN WADI ALLAQI, EASTERN DESERT, EGYPT

Vertical electrical resistivity and Bouguer gravity data were assessed at Wadi Allaqi area, Eastern
Desert, Egypt aiming at the configuration of the bedrock (basement) surface, potential of groundwater
availability and assessment ofthe best locations for drilling groundwater boreholes.
The results obtained from geoelectrical resistivity interpretation have shown that the interpreted depths
of basement surface range from about five m to sixty m with three main deeper troughs considered as best
locations for groundwater accumulation and suitable for drilling of groundwater boreholes. Since, the
gravity anomaly magnitude is mainly controlled by the depth to the subsurface causative feature
(basement) and its density contrast with overburden. Many trials for estimating the depth at varying
density contrasts (0.1-1.0 gm/cm3) were done. It is found that the closest depths from the gravity analysis
to the obtained resistivity analysis are the ones that were computed using the density contrast of 0.2
gm/cm3 as an optimum value. Finally, re-mapping bedrock topography based on that optimum value was
achieved.