الفهرس 
GEOLOGICAL SETTINGOnly 14 pages are availabe for public view
 |  | from | 157 |  |  |
| | | from | 157 | | |
Abstract
The greater Abu Swayel area is situated in the South Eastern Desert of Egypt (SED). It specifically covers the western section of the Allaqi-Heiani suture and spans over 2351 square kilometers. The area is located roughly 185 kilometers southeast of the city of Aswan and is bounded by latitudes 22o40’ N and 23o 02’ N, and longitudes 33o 12’ 30” E and 33o47’ E.
The area under investigation displays moderate topography. It is intersected by numerous wadis, which generally run in a NE-SW direction. These wadis include Wadi Nagib, Wadi Haimur, Wadi Umm Araka, Wadi Umm Ashira, Wadi Shilman, Wadi Shikeiyit, and Wadi Heisurba. The elevation values within the area range from 168-696 meters. The main geological components of the study area consist of pre-Cambrian basement complex rocks, including metavolcanic and metasedimentary rocks. These are responsible for the formation of island arc assemblages and ophiolitic groups. These groups form imbricate thrust sheets and slices of serpentinites, talc carbonate schist, and metagabbros rock associations. The area is also characterized by wadis filled with Quaternary alluvium, which are composed of sand, gravel, and rock fragments. These alluviums are generally formed by the weathering of previously-existing basement rocks.
The area being studied has a predominant surface structural lineament trend in the NE-SW direction, with other minor trends occurring in the N-S, NW-SE, WNW-ESE, and E-W directions. This summarizes the general structural setting of the area under investigation.
The gamma-ray spectrometric data are expressed in (µR/h), potassium (K) in percentage (%), equivalent uranium (eU), and equivalent thorium (eTh) in parts per million (ppm). Three ratios are derived from the three radioelement; eU/eTh, eU/K, and eTh/K. These seven variables are then arranged in a grid and color-coded to facilitate the interpretation of the distribution of radioelements in different surface exposed rock formations. The zonation maps for TC clearly display the contact and dimensions of alteration zones for the younger calc-alkaline granite of Gabal Magal Gabriel and the calc-alk qzdiorite to granodiorite of Abu Swayel area in terms of radiometric point of view. In addition, TC values range from 0.4 to 24 µR/h, eU values range from 1 to 19.4 ppm, and eTh values range from 0.5 to 31.1 ppm.
The factor analysis approach is utilized to conduct quantitative analysis, using seven variables namely TC, eU, eTh, K%, eU/eTh, eU/K, and eTh/K, to create three factors, namely F1, F2, and F3. These factors can help establish the spatial correlation of features present in different data sets while also displaying variations that may be difficult to identify. The scores of these factors are multiplied by 100 and then represented on a grid, with colors and contours added. Factor 1 can be recognized as the factor that indicates the level of radioactivity integration or the factor that indicates uranium exploration. Factor 2 is employed to distinguish between different types of rocks, while Factor 3 pertains to the basicity of the rocks.
The delineation of areas with uranium deposits was conducted through Saunders and Potts (1976) approach. This is done by comparing the average value of each rock layer with the published average value of the crust, and then creating a map that displays point anomalies. The first way for identifying anomalies is to determine the average uranium values for various rock units and then compare them with the published crustal average value for each rock type involved. This allows uranium-enriched units to be identified. When the average uranium value for each rock unit is compared with its corresponding crustal average, it becomes apparent that the Gabal Magal Gabriel’s calc-alkaline younger granite the only rock unit have uranium values that exceed the crustal average for acidic rocks.
The delineation of the uraniferous anomalous zone can be determined through a way method based on the calculation of properties that significantly differ from the average background data. Values that are higher than the mean background data are considered anomalous and are defined as those that are equal to or greater than two standard deviations from the calculated arithmetic mean values (X+2S) & (X +3S) for eU measurements, for a single point in each rock unit. An effective method was selected to differentiate between normal and abnormal measurements. The anomalous values were identified based on the technique proposed by Saunders and Potts (1976) that calculates the significant factor of each gamma-ray spectrometric variable in each rock unit. Such application revealed the presence of anomalous zones which require immediate ground follow-up. The study also showed that most of the identified gamma-ray spectrometric anomalies are closely linked to the surface faulting directions that exist in the region.
Stacked profiles help in facilitating the follow-up of anomalous zones on different gamma-ray spectrometric channels, using seven variables. These profiles are depicted on two flight lines, namely L890, and L930.
The aeromagnetic data were treated by several analysis techniques. Such techniques included reduction to the north magnetic pole (RTP), isolation of the regional and residual magnetic components through the Gaussian filtering technique, and magnetic depth calculation. Three methods were used for the magnetic depth calculation - the Source Parameter Image (SPI), Analytic Signal (AS), and Euler Deconvolution. The depth maps that were inferred indicate that the outcomes are quite similar to one another. By merging all of these methodologies, a magnetic basement tectonic map for the research region was produced.
The map of the tectonic basement indicates that the primary trend of the deep-seated structure in the study area is oriented NE-SW, while the secondary trends are oriented N-S and NW-SE. The near-surface structure of the study area is oriented primarily NNE-SSW and N-S, with secondary trends oriented WNW-ESE, NW-SE, and E-W.