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This contribution deals with new geology, petrography, and bulk-rock/mineral chemistry of the poorly studied ultramafics of Wadi Ibib–Wadi Shani (WI–WS) district, South Eastern Desert, Egypt. These ultramafics are dismembered ophiolitic rocks that can be subdivided into serpentinites and serpentinized peridotites. Primary minerals such as olivine and pyroxene are absent in serpentinites, but relics of them occur in serpentinized peridotites. Pseudomorph after olivine is indicated by common hourglass textures with less mesh, whilst schistose bastites reflect a pyroxene pseudomorph. Chromite can be subdivided into Cr-spinel and Al-spinel. Cr-spinel ranges from chromite to magnesochromite in composition, whereas Al-spinel belongs to the spinel field. Cr-spinel includes YCr (Cr/(Cr+Al+Fe+3), YAl (Al/(Al+Cr+Fe+3), and YFe+3 (Fe+3/(Fe+3+Al+Cr), similar to forearc peridotite, whilst Al-spinel is more similar to abyssal peridotite, and may be formed during inanition of subduction processes in proto forearc environments. The main secondary minerals are tremolite, talc, and chlorite—which is subdivided into pycnochlorite and diabantite—and their temperature ranges from 174 to 224 °C. The examined rocks had undergone high partial melting degrees (>25%), as indicated by the Cr# of their unaltered cores (Cr-spinel, >0.6), whole rocks (Al2O3, SiO2, CaO, and MgO), trace and REEs, depleted Na2O, Al2O3, and Cr2O3 of clinopyroxene, and high forsterite content ((Fo = 100 Mg/Mg + Fe), av. 95.23 mol%), consistent with forearc settings.

Radon concentrations have been measured using Sealed Can Technique with CR-39 detector for twenty collected samples from Hamash gold mine area, South Eastern Desert of Egypt. This area is one of the most important areas of gold-bearing granites in Arabian Nubian Shield and is being used as a gold mine. The average values of radon concentrations, the exhalation rates, annual effective doses, and working levels are found to be 27.18 ± 0.13 kBqm-3 , 3.27 ± 0.03 Bqm-2 h-1 , 686.27 ± 5.15 mSvy-1 and 2.94 ± 0.02 respectively. The results indicate that the radon concentrations in all samples are higher than the recommended world limit given by ICRP and IAEA. The present study can be used to assess any changes in the radioactive background and any harmful radiation effect on the human in this area. Finally, the obtained data are useful when building a radioactivity atlas of radon for Hamash gold mine and its surrounding region.