PETROGRAPHY, GAMMA RADIATION MEASUREMENTS AND DOSE RATE, NORTHEASTERN UM ARA AREA, SOUTH EASTERN DESERT, EGYPT | ||
| Nuclear Sciences Scientific Journal | ||
| Article 6, Volume 5, Issue 1, 2016, Pages 91-108 PDF (4.32 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/nssj.2016.30826 | ||
| Author | ||
| NASSER M. MOGHAZY | ||
| Nuclear Materials Authority,Cairo, Egypt | ||
| Abstract | ||
| The northern part of Um Ara alkali feldspar microgranite has subjected to extensive post-magmatic metasomatic reworking resulting in development of amazonitized and albitized zones, reflecting K- and Na metasomatism leading to gross enrichment in U and Th towards the more evolved phases (e.g., albitized zones). Spectrometric survey data indicate that eU in Dokhan volcanics has the range of 2 to 42 ppm with an average value of 10 ppm and in monzogranites. It varies from 3 to 13 ppm with an average of 7 ppm while in alkali feldspar microgranites eU contents vary from 3 to 282 ppm with an average value of 30 ppm. The (eTh) contents in Dokhan volcanics ranges from 5-51 ppm with an average 18 ppm, in monzogranites their content was in the range of 11 to 47 ppm with an average value of 27 ppm where it ranges from 14 to 83 ppm with an average 46 ppm in alkali feldspar granite. The enhanced uranium content in altered zones was attributed to disseminated and fracture filling uranophane, autonite, in addition to other U and Th bearing minerals (such as columbite, zircon, monazite, xenotime and fluorite). Gamma-radiation dose rate and annual effective dose equivalents in mSv/y, Radium equivalent activity, external (Hex) and internal hazard index (Hin) and gamma activity index (I) for all investigated samples were calculated to assess the potential radiation hazard for people living in dwellings made of the studied granites. Alkali feldspar granite activities would suggest that caution must be taken when using granites as building materials because they have radioactivity above the proposed acceptable level. | ||
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