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Egypt is mainly covered by ophiolitic rocks, muscovite, and two mica granites, in addition to different types of acidic and basic dikes. Our field observations indicated that El Sela granites were subjected to alteration types such as silicification, kaolinization, and hematitization, which is associated with uranium mineralization. Petrographic investigations clarified that these rocks were affected by saussiritization, muscovitization, and silicifications as the main alteration types associated with uranium mineralization (uranophane and autunite). We carried out chemical analyses of our samples for major oxides and trace and rare earth elements using ICP-OES and ICP-MS. The studied altered granites had high silica, titanium, and phosphorous as major components, with enhanced amounts of trace elements such as Nb, Ta, Zn, Mo, Pb, and Re, in addition to REE, especially light ones. The average REE content was higher than that of worldwide granites with LREE enrichment. One sample had a strong M-type tetrad effect in the fourth type; other samples had weak W-type in the third type, indicating the effect of hydrothermal alteration processes in the altered granites. This was confirmed by calculating the ratios of most isovalents that deviated from the chondritic ratio in many values. Variation diagrams of U and some trace elements illustrated that U had a weak positive correlation with Y and a strong positive correlation with gold, while it had weak to moderate negative correlation with Hf and Zr/U. In addition, uranium had a weakly defined correlation with the other trace elements, indicating a weak to moderate effect of magmatic processes, while the post-magmatic processes surficial or underground water greatly influenced the redistribution of uranium and other elements. [ABSTRACT FROM AUTHOR]

The existence of radioactivity linked to the heavy-bearing minerals in building materials—such as granite—has increased attention to the extraction procedure. Granite rocks play an essential economic role in various areas of Egypt. Thus, this study intended to detect the 238U, 232Th, and 40K activity concentrations in the examined granite samples and to determine the corresponding radiological risks associated with the granite. The studied rocks were collected in the Gabal Qash Amir area (south Eastern Desert, Egypt). The obtained results of the activity concentrations for 238U (193 ± 268) Bq/kg, 232Th (63 ± 29) Bq/kg, and 40K (1034 ± 382) Bq/kg indicated that there were moderate concentrations in the investigated samples, which were greater than the worldwide average. The radioactivity levels in the studied granite samples are due to the secondary alteration of radioactive-bearing minerals associated with cracks of granites (secondary minerals in muscovite granites are wolframite, uraninite, uranophane, beta-uranophane, autunite, xenotime, columbite, zircon, and monazite). The radiological risk assessment for the public from the radionuclides that were associated with the studied granite samples was predicted via estimating the radiological hazard factors, such as the radium equivalent content (362 Bq kg−1), compared with the recommended limit. The dosing rate Dair in the air (169.2 nGy/h), the annual effective dose both outdoors (AEDout ~ 0.21 ± 0.17 mSv) and indoors (AEDin ~ 0.83 ± 0.67 mSv), the annual gonadal dose equivalent (AGDE ~ 1.18 ± 0.92 mSv), as well as the external (Hex) and internal (Hin) hazard indices (>1), and another factor were associated with excess lifetime cancer risk. According to the statistical investigation, the studied granites were inappropriate for use in construction and infrastructure fields. They may induce health problems due to the radioactivity levels, which exceed the recommended limits. [ABSTRACT FROM AUTHOR]

Different rock types (syenogranite, alkali feldspar granite and quartz syenite intruded by microgranite dikes and quartz veins) were investigated in the Nikeiba region in Egypt. The main components of the studied intrusive rocks, comprised of granites and quartz syenite, are plagioclase, amphibole, biotite, quartz and K-feldspar in different proportions. Ground gamma ray measurements show that syenogranite, quartz syenite and microgranite dikes have the highest radioactivity (K, eU, eTh and their ratios) in comparison with alkali feldspar granite. Geochemically, syenogranite, alkali feldspar granite and quartz syenite are enriched with large-ion lithophile elements (LILE; Ba, Rb, Sr) and high field-strength elements (HFSE; Y, Zr and Nb), but have decreased Ce, reflecting their alkaline affinity. These rocks reveal calc–alkaline affinity, metaluminous characteristics, A-type granites and post-collision geochemical signatures, which indicates emplacement in within-plate environments under an extensional regime. U and Th are increased in syenogranite and quartz syenite, whereas alkali feldspar granite shows a marked decrease in U and Th. The highest average values of AU (131 ± 49 Bq·kg−1), ATh (164 ± 35) and AK (1402 ± 239) in the syenogranite samples are higher than the recommended worldwide average. The radioactivity levels found in the samples are the result of the alteration of radioactive carrying minerals found inside granite faults. The public's radioactive risk from the radionuclides found in the investigated granitoid samples is estimated by calculating radiological risks. The excess lifetime cancer (ELCR) values exceed the permissible limit. Therefore, the granitoids are unsuitable for use as infrastructure materials. [ABSTRACT FROM AUTHOR]

Younger granite bodies form two arches, the western and the eastern (WA, EA), which extend from the south northwards from the Meatique, ophiolitic group-island arc rocks, to the large older granite outcrop to the north. This paper concerns the feasibility of exploration in the El-Erediya-Ria El-Garah-El-Gidami-El-Missikat Y Gr regions. Fieldwork and remote sensing, together with geochemical, petrochemical, and mineralogical studies, are used to show the controlling factors, routes, and the origins of the deposits. Remote sensing is used to delineate the different rock units. Normal and strike–slip NW, NNE faults, veins, fractured ENE shear zones, and alteration zones of magmatic-hydrothermal fluids are discussed. Granites are considered using petrochemical diagrams as resources. These rocks are categorized as syeno- and alkali feldspar granites. Geochemical binary relationships recognized the granites are highly fractionated calc-alkaline-altered Monzo-, syeno-, and alkali feldspar granites formed in the active continental margin. The observed positive Ga vs. Cu, Zn, and Ni correlations are used for epithermal-magmatic-hydrothermal polymetallic veins and mineralized greisen zones. Negative Cu vs. Mo correlation patterns show probable Mo-porphyry deposits in the deeper zones at the contact point between porphyritic perthite and perthite granitic El-Erediya mass. The Zr/Sr between 1.65 to 2.93 plus fluorites in El-Missikat and up to 5.48 plus fluorites in El-Erediya show both U-poor at El-Missikat and U-rich deposits at El-Erediya. The recorded U, Th, Cu, and Pb vertical zoning sequence of deposition differentiates U aureole and deposit zones. The estimated lateral zoning sequences of deposition of these elements define the centers of U deposits. Pathfinders for the deposit of the examined area include the positive Fe2O3 vs. Mg O and Fe2O3 vs. Ca O correlations, and also negative Rb/Sr vs. K/Na and Rb vs. Sr ones, can be applied to future prospecting for similar U-F-Au-W-Mo deposits in the Eastern Desert of Egypt. [ABSTRACT FROM AUTHOR]

Arranged from oldest to youngest, the main granitic rock units exposed in Khour Abalea are metagabbros, cataclastic rocks, ophiolitic melange, granitic rocks, pegmatite and lamprophyre dykes. The presence of radioactivity associated with the heavy bearing minerals in construction materials—like granite—increased interest in the extraction process. As it turns out, granitic rocks play an important economic part in the examination of an area's surroundings. The radionuclide content is measured by using an NaI (Tl)-detector. In the mineralized pegmatites, U (326 to 2667 ppm), Th (562 to 4010 ppm), RaeU (495 to 1544 ppm) and K (1.38 to 9.12%) ranged considerably with an average of 1700 ppm, 2881.86 ppm, 1171.82 ppm and 5.04%, respectively. Relationships among radioelements clarify that radioactive mineralization in the studied pegmatites is magmatic and hydrothermal. A positive equilibrium condition confirms uranium addition to the studied rocks. This study determined 226Ra, 232Th and 40K activity concentrations in pegmatites samples and assessed the radiological risks associated with these rocks. The activity concentrations of 226Ra (13,176 ± 4394 Bq kg−1), 232Th (11,883 ± 5644 Bq kg−1) and 40K (1573 ± 607 Bq kg−1) in pegmatites samples (P) are greater than the global average. The high activity of the mineralized pegmatite is mainly attributed to the presence of uranium mineral (autunite), uranophane, kasolite and carnotite, thorium minerals (thorite, thorianite and uranothorite) as well as accessories minerals—such as zircon and monazite. To assess the dangerous effects of pegmatites in the studied area, various radiological hazard factors (external, internal hazard indices, radium equivalent activity and annual effective dose) are estimated. The investigated samples almost surpassed the recommended allowable thresholds for all of the environmental factors. [ABSTRACT FROM AUTHOR]

The occurrence of heavy radioactive minerals in construction supplies such as granite has drawn attention to the extraction of heavy radioactive minerals. Granitic rocks were identified to serve an essential economic role in the study area's surrounding locations. As a result, the current study attempted to detect the activity concentrations of 238U, 232Th, and 40K in the granitic rock samples tested and estimate the radiological dangers associated with these rocks. The obtained data on activity concentrations for 238U (610 ± 1730 Bq kg−1), 232Th (110 ± 69 Bq kg−1) and 40K (1157 ± 467 Bq kg−1) in the granitic samples (GR) were higher than the recommended worldwide average. The radioactive levels found in the samples were caused by radioactive materials being altered and trapped inside granite faults. The exposure to gamma radiation from the granitic rocks were assessed via various radiological parameters, such as radium equivalent content (856 Bq kg−1), absorbed dose rate (Dair) in the air (396 nGy/h), and annual effective dose for either outdoor (0.48 mSv y−1) or indoor (1.9 mSv y−1). Statistical analysis was performed to detect the correlations between radioactive concentrations and radiological parameters. The radioactive effects contributed by the uranium minerals were associated with the granitic rocks. Based on the analysis, the radioactive levels in the examined granitic surpassed the acceptable limits; therefore, they are not safe to use in building and infrastructure applications and may cause adverse health effects. [ABSTRACT FROM AUTHOR]

The present study aims to assess Abu Rusheid and Um Naggat albite granite's natural radioactivity in the Central Eastern Desert, Egypt, using an HPGe laboratory spectrometer. A total of 17 albite granite samples were detected for this study. The activity concentrations were estimated for 238U (range from 204 to 1127 Bq/kg), 226Ra (range from 215 to 1300 Bq/kg), 232Th (from 130 to 1424 Bq/kg) and 40K (from 1108 to 2167 Bq/kg) for Abu Rusheid area. Furthermore 238U (range from 80 to 800 Bq/kg), 226Ra (range from 118 to 1017 Bq/kg), 232Th (from 58 to 674 Bq/kg) and 40K (from 567 to 2329 Bq/kg) for the Um Naggat area. The absorbed dose rates in the outdoor air were measured with average values of 740 nGy/h for Abu Rusheid albite granite and 429 nGy/h for Um Naggat albite granite. The activity concentration and gamma-ray exposure dose rates of the radioactive elements 238U, 226Ra, 232Th and 40K at Abu Rusheid and Um Naggat exceeded the worldwide average values that recommend the necessity of radiation protection regulation. Moreover, the corresponding outdoor annual effective dose (AEDout) was calculated to be 0.9 and 0.5 mSv y−1 for Abu Rusheid and Um Naggat albite granite, respectively, which are lower than the permissible level (1 mSv y−1). By contrast, the indoor annual effective dose (AEDin) exceeded the recommended limit (3.6 and 2.1 for Abu Rusheid and Um Naggat, respectively). Therefore, the two areas are slightly saving for development projects concerning the use of the studied rocks. The statistical analysis displays that the effects of the radiological hazard are associated with the uranium and thorium activity concentrations in Abu Rusheid and Um Naggat albite granites. [ABSTRACT FROM AUTHOR]