GROUND GEOPHYSICAL-STUDY FOR DEVELOPMENT AND EXPLORATION OF EL-MISSIKAT RADIOACTIVE MINERALS PROSPECT, CENTRAL EASTERN DESERT OF EGYPT

The El Missikat area lies in the Eastern Desert of Egypt, 85 km west of Qena town. The area being studied is covered mainly by pink granite, quartz-diorite rocks and wadi deposits. The importance of the area originates from previous studies, including airborne geophysics, surface geology and mining geology which indicate that the area has features of radioactive mineralization at the northeastern periphary of G. El Missikat. The present study deals with the use of ground geophysical methods (total-count radiometric and magnetic) in the exploration of radioactive mineralization acid their relation to the geology and structural pattern of the area. The ground total-count radiometric method is used to describe the radioactivity of different rock units and the construction of the standard deviation (or anomaly) contour map to define the anomalous radioactive zones. Eight prominent radioactive anomalies were outlined from this study and they represented targets of high priority for ground follow-up. Accordingly, to emphasize the extension of the anomalous zones at the subsurface, gamma-ray logging was carried out on a total-count basis in one inclined drill hole (120 m depth) with dip angle 29 and azimuth N20 degrees W at a selected location. In addition five subsurface radiometric anomalies were identified by gamma-ray logging interpretation. The interpreted radioactive anomaly No. IV is considered a good indication of the subsurface continuity of a surface mineralized zone associated with the silica vein which was geologically mapped at the north of El Missikat well number II. Meanwhile, the total magnetic intensity survey was used to delineate the major structural Features. The results of this study revealed the presence of six major, deep-seated faults, five basement tectonic blocks, basic or/and acidic zones, near-surface faults, contact between granite and quartz-diorite and several shear zones as well as dykes and veins. The integration between results of these two methods guided the development of exploration and solved many problems that were obscure for the field geologists and mining works in the area studied. It could also help in defining the radioactive mineralized zones, and their setting in depth. Also, it was observed that the interpreted radioactive anomalies are associated with acidic shear zones which may be due to hydrothermal solutions that percolated through, or around, these shear zones.