干旱区生态环境知识资源中心

The El-Missikat prospect Lies in the Eastern Desert of Egypt, 85 km from Qena along the river Nile. The area of the prospect is covered by pink granites of the Gabal (G.) El-Missikat pluton from the south and quartz diorite from the north, as well as wad alluvium at Wadi El-Missikat, which passes through the study area from south to north. The importance of the study area comes from previous studies, airborne geophysics, surface and mining geology and ground spectrometric and magnetic studies, which prove that the area has radioactive mineralization zones at the northeastern periphery of G. El-Missikat. These mineralized zones lie along northeast-southwest jasperiod veins and shear zones which occur inside the granitic rocks.

The previous studies concluded that the radioactive mineralization was mostly associated with sulphides, especially at the reduction zones. These sulphides give a good response to electrical or electromagnetic techniques. Accordingly, the present study uses self potential, electrically induced polarization and horizontal loop electromagnetic surveys to explore the extension of the mineralization zones at the subsurface.

The self potential (SP) technique shows that there are numerous (31) mineralized zones. Most of these zones are distributed in the southern part of the area along the contact between the quartz diorite, the granite and the shear zones inside the El-Missikat granitic pluton. In addition, the induced polarization (IP) method is applied on two selected profiles (450E and 500E) to delineate the subsurface contact between granite and quartz diorite in Wad El-Missikat and to calculate the shape and depth of the mineralization zones in the subsurface along these profiles. The horizontal loop electromagnetic survey, which was applied on three selected profiles, delineated some weak mineralization occurrences corresponding to the shear zones.

The integration of the results obtained using these three techniques, in addition to the different ground geophysical methods prviously used, make it possible to determine the most appropriate zones for developement of exploration at the area of investigation.