No abstract

Elmissikat-Eleridiya district is one of the most important uranium localities in the central Eastern Desert of Egypt. The feature oriented principal component selection (FPCS) and spectral angle mapper (SAM) techniques were applied on ASTER L1B imagery for mapping the common alteration zones. The study revealed that ASTER VNIR-SWIR bands are effectively used for delineating sericite, kaolinite, chlorite, illite and hematite bearing alteration zones, whereas ASTER TIR bands are most effective in delineation of silica-rich zones, which associate and could be used as pathfinder for radioactive mineralization within the study area. The resultant alteration maps show good coincidence with the explored uranium sites and suggest further similar unexplored sites. The results could assist the development of uranium exploration in the study area and other similar localities within the Egyptian deserts.

Detailed geological mapping description of the different granitic types of Kab Amiri pluton were integrated with geophysical (ground gamma ray spectrometry and aeromagnetic) data to identify and map the distribution of radioelement concentrations as well as delineate structural trends that control the mineralized zones in the study area. The geologic studies revealed the existence of four granite varieties namely; biotite granite, garnet two mica granite, muscovite granite, and episyenite. The structural interpretation of geological and geophysical data revealed two intersecting sets of NW and NE-trending faults. The NW-trending set of faults is younger than the NE-trending set where the latter is dissected and displaced by the former. Interpretations of radiometric data revealed the presence of radioactive anomalies southwards that indicate an original increase in uranium contents in the same direction. It could be related to the prevailing NE and ENE fault trends. The southern anomalous zone is related to a very high episyenitization and uranium mobilization. It exhibits a sharp increase in the eU concentrations reaching 370 ppm resulting in a high eU/eTh ratio, approaching 4.5 and, characterized by oval shape trending in the NE direction. Some areas along the peripheral part of Kab Amiri pluton are episyenitized and show a remobilization of uranium. These areas are mostly controlled by faults mainly trending ENE. In the case of the episyenite zone, strong mobilization of uranium is expected to host epigenetic uranium occurrences because more uranium is available. It is obvious that the episyenite rocks of high permeability have higher levels of uranium and their ratios. Thus, these rocks act as an important reservoir for Umineralization bearing solutions.

The present work used the integrated remote-sensing and ground gamma-ray spectrometric data to prospect of radioactive zones at Gabal Qash Amer-El-Sela area, Southeastern Desert of Egypt. Geological interpretation of ASTER image correlated with field studies revealed that the study area is mainly covered by intermediate metavolocanics, granodiorites, two-mica granites, biotite granites and muscovite granites. These rocks were injected by pegmatitic and quartz veins and cutting by acidic and basic dykes. The applied ASTER data enabled to identify uraniferous alteration zones hosted in the granitic rocks through the use of band ratios b4/b6 and b5/b4 for clay and ferrous silicate alteration. The band ratio combinations of b12/b13: b11/b12: b14/b13 as R:G:B and b4/b6:b2/b1:b4/b3 as R:G:B were very useful for discriminate the granites from the metavolcanics and mapping different phases of the granite in the study area. Ground gamma-ray spectrometric survey data were applied to check the surface distribution of radioactivity, which may ascertain its compatibility with surface structures, and delineate the suitable locations for probable valuable mineralization. The study revealed the existence of uranium mineralization in alteration zones associated with granites, along ENE-WSW trending shear zones as well as other isolated alteration zones. Three uranium-bearing alteration zones hosted in granities were detected. These zones are characterized by ferrugination, silicification, grizenization and kaolinitization. The most promising alteration zones occur at the northeastern part of El-Selashear zone. Another promising uranium anomaly is located to the west of the main shear zone, as well as third anomaly, located at the southeastern part of Gabal Qash Amer. These zones and individual anomalies are characterized by very high radioactive anomalies (up to 3700 ppm eU). Other mineralized sites were detected in the south central part of Gabal El-Selaas well as in the eastern part of the study area. The final result of this study confirms that El-Sela granite can be considered as one of the most promising granite outcrops in Egypt, regarding its U-fertility.

The present study deals with the analysis of data from a ground magnetic survey that was conducted in the AbuRodaym area of the Southwestern Sinai Peninsula, Egypt. This survey was carried out to delineate the subsurface structural framework, and to identify the thickness of the sedimentary basin of the study area. Locating these structures, and determining the localities of maximum sedimentary thicknesses that consist mainly of sandstone, serves as a preliminary process in exploring the confined aquifer beneath the surface of the Abu-Rodaym area. This will greatly benefit Bedouins who suffer greatly from a lack of water in the driest region in the country. The processing, analysis, and interpretation, of the total intensity magnetic data shows that there are three sets of faults striking mainly in the N-S, NW-SE, and NE-SW, directions. The depth to the basement surface was found to fluctuate from about 45 m, to more than 100 m, beneath the ground surface. It was also found that the variations in magnetic observations were produced by the striking structures that are mainly responsible for the variations in thicknesses of the sedimentary rocks in the area.