Horizontal-loop electromagnetic (HLEM) and self-potential (SP) surveys were conducted to follow the extension of the exposed mineralized shear zone at depth and to detect any possible subsurface mineralization, its probable extension, and its structural setting. This may affect the distribution of radioactive and other associated minerals at Abu Rusheid area located in the south Eastern Desert of Egypt.
The HLEM data were collected using four frequencies (110 Hz, 440 Hz, 3520 Hz and 14080 Hz) and two coil separations (80 m and 140 m). The interpretation of these data indicated the presence of two strong conductive zones trending in the NNW-SSE and NW-SE directions. These strong zones are dissected by a moderate conductive zone trending in the NE-SW direction. The target parameters, as estimated from the HLEM data revealed that, their widths range between 10 m and 80 m, depths to the top are shallow and vary from 13.6 m to 58 m, dip angles range between 36° and 82° to the east and west, and conductance (σt) changes from 18.4 S to 135.2 S. Moreover, a small area is selected for the SP survey to follow the observed radiometric anomalies at depth. The results indicated the existence of a series of conductive zones corresponding, in many places, to the previous identified radiometric zones.
The integration of the results revealed that, the SP and HLEM anomalies are related to shear zones and faults, as well as lamprophyre and quartz veins. Most of these anomalous zones are opened towards the north; this may attract the attention to the continuity of mineralization northwards. In addition, the NNW-SSE, NW-SE and NE-SW trending structures are of prime importance and can be considered as significant targets for further field investigations in the study area and its surroundings.