干旱区生态环境知识资源中心

Regional radiometric-geological mapping of the outcropping basement complex in the Gabal Eteiqa area has been carried out through the application of factor analysis technique.

Three factor scores (F--1, F--2 and F--3), which reflect the interrelation of the seven spectrometric variables (TC, eU, eTh, K, eU/eTh, eU/K and eTh/K), are sufficient to outline the different rock units. F--1 outlines the highly-radioactive rocks such as granodiorites, granites, ring complexes and acidic volcanics. The granodiorite and ring complexes are completely differentiated by F--2 scores. The F--3 values enable the granitic plutons to be divided into numerous subunits (e.g. G(1), G(2), G(3) and G(4)). It is believed that the low radiometric level of G(4) is due to the Quaternary wadi deposits that overlie the granites, an interpretation confirmed by aerial photomosaics.