An analysis of airborne gasamma ray spectrometric data of Gabal Umm Naggat Granitic Pluton, Central Eastern Desert, Egypt

الملخص EN

The present work deals with the analysis of the airborne gamma ray spectrometric data of Gabal Umm Naggat granites, Central Eastern Desert, Egypt.

It shows distinct spectral pattern of the radioelement zoning which is related to the associated mineralogical variation of such granitic pluton.

The pluton is divided into three spectral domains : northern, middle and southern.

The northern domain (A) is characterized by high radioelements contents and high ratios.

It is characterized by high Zr, Nb, Y, Th, U and HREE in the most albitized granite varieties.

The middle domain (B) is K, Th rich reflects the alkali feldspar rich granite.

The southern domain (C) is characterized by high three radioelements contents, but lower than the northern one.

Such zonation is evidenced by the results of geochemical analysis of previous works.

To assess the potentiality of the gamma ray spectrometric signatures of areas of change associated with hydrothermal Nb-Ta-Sn occurrences, two approaches such as residual anomaly method on the basis of lithologic normalization (Th-normalized approach) and the Fparameter of Effimov approach are applied.

Low anomalous potassium (Kd) that connected with high anomalous uranium variation (Ud), and high F-parameter anomaly strip highlight areas of change associated with hydrothermal Nb-Ta-Sn occurrences.