Abstract
This study deals with using the least-squares method (LSM) to separate the absolute aeroradiospectrometric maps (T.C., K-40, eU, and eTh) into highly radioactive zones and the normal radioactive background of the host rocks. The Gabal Um-Rabul area, selected for testing the efficiency of the present method, lies in the northern part of the Eastern Desert of Egypt and is covered mainly by Precambrian basement rocks, which are unconformably overlain by Phanerozoic sedimentary successions.
In the present study, the least-squares (first-order) residual anomaly analysis method was used and contour maps were drawn to delineate the significant aeroradiospectrometric anomalies over the study area. It was found that, the least-squares first-order regional and residual total-count (T.C.) and the three absolute radioelements (K, eU, & eTh) maps of the study area show a high degree of coincidence with the anomalous maps constructed by the conventional statistical methods in terms of the locations, intensities, and trends of anomalous zones. Therefore, it is recommended to apply the least squares method for locating radioelements anomalous zones in any surveyed area.