干旱区生态环境知识资源中心

The present study deals with the airborne gamma-ray spectrometric and magnetic surveyed data of W. Um Geheig-W. Abu Eligam area, Egypt. These two methods have been utilized in order to investigate the surface and subsurface features affecting the structural framework and to find any relation between the radioactive elements and structures as well as to determine the environmental dose rates in the study area. The results show that the study area has some eU, eTh, and K% anomalies related to the biotite granites and are structurally controlled by the dominated faults. The calculated dose rates in the study area, ranging between 0.1 and 1.1 mSv/year, indicate that the study area as whole remains in the safe side and under the maximum permissible safe radiation dose rate without harm to the individual, with continuous external irradiation of the whole body. Magnetic data have been subjected to various techniques such as 3-D Euler deconvolution, edge enhancement, and magnitude magnetic transform techniques. 3-D Euler deconvolution technique is mainly utilized for depths and structural index estimations. The estimated depths varied between 0.246 and 1.151 km with average depth of about 0.648 km, and structural indices varied between 0.019 and 1.07 with average structural index of about 0.367, indicating mostly a magnetic contact model. The edge enhancement showed that the area has distinctive edges that are trending NNW-SSE, E-W to ENE-WSW, WNW-ESE, and minor N-S directions. Magnetic magnitude transforms show some zones having remnant magnetization, shallowest causative targets, as well as structural contacts having the same direction as the edge enhancement technique. The integration of the results of magnetic and gamma-ray spectrometric interpretations reveals that most of radiometric anomalies recorded in the study area lie over the younger granites which are distributed as isolated bodies aligned around the big mother batholith dissected mainly by NW-SE, NE-SW, and E-W faults.