GEOLOGY AND RADIOACTIVITY OF ALKALINE GRANITES OF SOUTHWEST GABAL NUSAB EL BALGOUM AREA, SOUTH WESTERN DESERT, EGYPT | ||
| Nuclear Sciences Scientific Journal | ||
| Article 8, Volume 4, Issue 1, 2015, Pages 115-132 PDF (1.75 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/nssj.2015.30925 | ||
| Authors | ||
| ADEL A. ARBAB; NASSER M. MOGHAZY; ATA ABDELSHAFY | ||
| Nuclear Materials Authority,Cairo, Egypt | ||
| Abstract | ||
| This paper is concerned with the geology and radioactivity of alkaline granites southwest Gabal Nusab El Balgoum area, South Western Desert, Egypt. The alkaline granites are equigranular in texture, fine- to medium-grained and dominated mainly by perthitic orthoclase and quartz, aegirine-augite, aegirine, and plagioclase, while Bastnaesite, xenotime, calcite, monazite, zircon and apatite are accessory minerals. Opaques represented by Hematite, ilmenite, goethite and little sulphides (chalcopyrite and pyrrhotite). Applying alpha-track emission technique indicates that iron oxides and altered feldspar minerals contain great amount of radio-elements (U and Th). Representing field radiometric contour maps for eU, eTh (ppm) and K% indicate that U and Th concentrate in the main fault trend NE-SW, which suggest that the enrichment of U is structurally controlled. A difference between field measurements (eU and eTh) with the chemical analysis data (U and Th) can be explained due to recent U addition. The trace elements contents show that Zr, Nb, Y (HFS elements) values increase with increasing U due to hydrothermal alteration at later stages of magmatic activity. Chondrite normalized REE diagram shows that the alkaline granite has enrichment of " REE and display progressive enrichment in LREE relative to HREE which shows a slightly flat pattern with large negative Eu anomaly. The enrichment of REEs may be attributed to the presence of bastnaesite and monazite as a source of LREE and xenotime as a source for HREE. | ||
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