Estimation of the natural radioactivity levels and rare earth elements concentration in the granitic rocks, Gabal Ghareb, Eastern Desert, Egypt

In this study, the major, rare earth elements and the natural radioactivity of thorium, radium, and potassium radionuclides of the granitic rock samples collected from Gabal (mountain) Ghareb, Eastern Desert of Egypt were determined. Inductively coupled plasma atomic emission spectrometry (ICP-AES), mass spectrometry (ICP-MS) and high purity germanium detector (HP Ge) were used. The geologic and radiometric surveys on Gabal Ghareb indicated that uranium mineralization is associated with shear zones and fractures following NNE–SSW and NW–SE. The uranium mineralization is localized along the NNE–SSE faults and trapped by fractures cutting these shear zone in the eastern part of Gabal Ghareb. The predominant rock types are granites, granodiorites, granosyenites and syenites of geochemical peraluminous character. The variation in the major oxides and REE elements concentration reflects magmatic differentiation and post magmatic hydrothermal alterations for the investigated samples. The radiological parameters measured are: radium equivalent activity index Raₑq (199.89 Bq/kg), absorbed dose rate ADR (94.25 nGy/h), annual effective dose equivalent AEDE (0.46 mSv/yr), gamma index Iɣ (0.74), alpha index Iα (0.26), annual gonadal dose equivalent AGDE (668.10 μSv/yr), excess lifetime cancer risk ELCR (1.62 × 10–³), external and internal hazard indices Hₑₓ and Hᵢₙ (0.54 and 0.68). The multivariate Dendrogram cluster analysis showed good agreement with each other. A great care should be taken in consideration when dealing with the Ghareb rocks, as they cannot be used as construction material due to their radiological threat to population and radiation protection precautionary measures must be taken. Comparison between the radiological parameters of other areas from the northern and southern parts of Egypt were given.