INTEGRATION OF AIRBORNE AND CARBORNE GAMMA RAY SPECTROMETRIC SURVEYS,WADI ELGIDAMI AREA, CENTRAL EASTERN DESERT, EGYPT

Qualitative interpretation was executed on the airborne and car-borne spectrometric data of Wadi Elgidami area and its surroundings, Central Eastern Desert, Egypt. Elmissikat younger granites are characterized by increase in the three main radioactive elements; up to 5.6% K, 30 ppm eU and 60 ppm eTh and found in the eastern part of the study area. The western part of the study area includes Dakhla Formation which contains uranium-bearing phosphate beds. They are characterized by increase of uranium up to 42 ppm without potassium or thorium enrichment. Radioactivity level decreases strongly in older granites and the surrounding country rocks. Stacked profiles were used to correlate the three radioelements and their ratios for both airborne and car-borne data. It was found that the radioelement profiles of airborne data agree well with that obtained by car-borne survey. Both of them show that phosphates are the dominant rocks that effectively contribute to eU anomalies, occurring in the study area. The three-dimensional and composite image maps for eU and (eU/eTh) reveal that there are two important anomalies, in the younger granitic rocks, located in the southwestern and northwestern parts of the study area; both are connected to the Dakhla Formation, which contains phosphate beds. The northwestern anomaly seems to represent the highest one in the study area and, hence, is considered very important from the eU point of view and needs more detailed studies.