الفهرس 
CHAPTER ONE INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 159 |  |  |
| | | from | 159 | | |
Abstract
The present study deals with geochemical prospecting for radioactive minerals using both panning and stream sediments samples at Gabal Um Naggat and Gabal El Atawy area, Central Eastern Desert. The area of study lies between latitudes 25◦26`–25◦40`N and longitudes 34◦06`–34◦18`E. Geologically, the area comprises a wide variety of basement rocks including (from older to younger); serpentinites and related rocks, metasedimentary rocks, metagabbros, metavolcanics, older granitoids, Hammamat sedimentary rocks, younger granites and trachyte plugs and sheets. The content of fifteen trace elements are measured in fifty-seven samples (Thirty-two stream sediment samples and twenty-five panning samples) collected from Wadi El Miyah and Wadi Um Diwan. The results are exhibited in a series of geochemical distribution maps, and are treated statistically by R-mode factor analysis.
The study area is subjected to field and laboratory radiometric survey for its stream sediments and the concentration of eU is ranging from 1.0 ppm to 38 ppm with an average 14.19 ppm while the concentration of eTh is ranging from 2.0 ppm to 82 ppm with an average 33.2 ppm.
The panning samples are subjected to a series of concentration process using some methods of density separation, often in combination with sizing and magnetic separation. The average content of the heavy minerals in the panning samples at G. Um Naggat and G. El Atawy is 21.66%, ranging from 13.25% to 34.11%. The mineralogical investigation of the heavy minerals revealed the presence of considerable rare metals and radioactive minerals (pathfinder minerals) such as columbite, zircon, thorite, fluorite and xenotime. The weight percentages of these pathfinder minerals are calculated. Columbite is the most common heavy minerals in the study area. Its concentration is ranging from
III
0.17% to 0.78% with an average 0.46%. The average content of zircon is 0.17%, thorite is 0.12%, fluorite is 0.10% and xenotime is the least common with an average of 0.09%. It is noticed that the above-mentioned minerals are mostly concentrated at the northeastern part of Gabal Um Naggat in the study area due to the presence of the albitized and greisenized granites. .
The geochemical data results of radiometric and x-ray fluorescence analysis for both stream sediments and panning samples are treated statistically (univariate and multivariate). The very high and moderate correlation obtained between (Zr, Nb, Y, Zn and Rb) and (eTh, eU and eRa) confirm the close association of these elements in the heavy minerals placer among the wadi deposits and suggest the use of these elements as indicator or pathfinders elements for radioactive and nuclear metal located in proximity metasomatized parts of granite (Apogranite zones) during the panning exploration survey. The R- mode factor analysis reduced the large datasets into four factors together explains 81, 37 % % of the variance in the original data. Factor 1 is dominated by radioactive element such as (eU, eTh, eRa, Rb and Zn) so that we can refer to it as radioactive mineralization factor. Second factor is dominated by (Zr, Nb and Y) so that we can refer to it as pathfinder factors. Factor 3and 4 are dominated by chalcophile elements so that we can refer to them as an environmental factors.