الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The future of Egypt’s economy and development is challenged by the exploration of its mineral resources. Many of these mineral deposits are still poorly mapped and defined, despite the fact that there are various geological metallogenic maps accessible. Using satellite imaging technology and modern earth observational techniques, it is possible to discover alteration zones holding rich mineral deposits as well as determine their precise location and extent. The extraction of alteration mineral zones and lithological discrimination as a strategy for gold exploration were showing tremendous promise when new approaches for ASTER multispectral data and gamma-ray spectrometric data are combined.
An enhanced lithological map and the main lithological units have been identified using a combination of remote sensing methods, including FCC, CRC, PCA, and MNF. Additionally, methods like MTMF, SAM, and SID helped to define the alteration zones related to gold mineralization. The alteration zones generated by the presence of the specified alteration minerals using the three classification approaches had the same positions. Using the selected approaches for alteration mapping and the automatically derived lineaments, the majority likely locations for zones of mineral-bearing hydrothermal alteration were defined. The main alteration minerals that were extracted overlap with areas of high/moderate lineament density, demonstrating the spatial distribution of alteration zones and related minerals in the research area. As a result, regions with comparable circumstances were thought of as possible mining exploration zones. The lineament density map will be even more useful when combined with details about the area’s alteration zones, which have been effectively characterized using a variety of methodologies.
Gamma-Ray Spectrometric data was utilised for mapping the alterations caused by hydrothermal activity. The eTh ppm, K %, and eU ppm maps were employed as enhancement techniques. It is showed that the magmatic intrusion and hydrothermal alteration processes that caused the alteration were significantly related to a decrease in thorium and uranium and a rise in potassium throughout regional tectonic activity. Potassium is frequently the significant valuable element for regions of gold mineralization because of the high concentration in the altered rock that surrounds the deposits. Wherever gold-related alterations were discovered in quartz veins, these veins are typically having low radioelements; however the hydrothermally altered host rocks typically have a distinctive signature of radioelement that is helpful for investigation.
Regarding the radioelement composite map, the high colour values are clearly identified from the low radioactive rocks by their significant geographic correlation with the abnormally high concentrations of K, eU, and eTh, and are often defined by their strong radiometric responses. The eU-(eTh/3.5) map illustrates how uranium was mobilized toward the mineralized zone as altered rocks were subjected to hydrothermal fluids which could lead to mineralization.
Regarding the eTh/K ratio, when it is low, it is considered one of the ideal markers of potassium alteration. Because enriched uranium occurs related to the potassium anomaly, radioelement ratio maps, such as the eU/K and eU/eTh maps, highlight the effects of hydrothermal activity. Regions with anomalies with high F-parameter values are those where potassic alterations have had a significant impact. Thorium normalizing method in which locations with anomalous low Kd percent coupled to abnormal uranium variation Ud percent are recognized as prospective mineralization hotspots.
As a result of the integration of remote sensing and gamma-ray spectrometric techniques, five potential gold prospecting regions have been suggested; gold mineralization is more probable in locations with alteration minerals that correspond with high lineament density. Furthermore, possible locations proposed by the Th-normalization and F-parameter approaches will be considered the overwhelming probable to contain alteration minerals. The contacts between the various rock groups in the research region were clarified on a final integrated lithological alteration map, which also identified the gold-related altered zones for gold exploration.
The widely dispersed metagabbro-diorite rocks that contain malacite-sulphides are the host of the Um Balad gold occurrences. These rocks have mostly been sheared and fractured, exposing alteration minerals along the weakness zones and fractures. They exhibit minimal deformation, poor banding, and occasionally blocky weathering. Depending on the amount of feldspar, mafic minerals, and quartz, the mineral composition of metagabbro-diorites can range from diorite to gabbro and, locally, quartz diorite. Three modest gold mining locations, all of which are situated along metagabbro-diorites in sheared zones. A number of milky-smoky quartz veins with varying thicknesses varying in length from a few meters to tens of meters are carving the local rocks. They have a 1 km range, are mostly trending in the NW-SE, and have a vertical to subvertical dip. The majority of these quartz veins were dug up and used as gold mines, but some may be gold bearing and are still being investigated.
The quartz veins systems are primarily restricted to sheared and altered zones, while they can occasionally be dispersed and injected randomly in the country rock units. The metagabbro- diorites are influenced by numerous shear zones and hydrothermal alteration zones as a result of the granitic intrusions because of the diverse tectonics and structural features at Um Balad area. The rocks are foliated, fractured, and impacted by brittle deformation along the shear zones.
A field investigation was carried out to investigate the lithology, the geological features, the connections between the exposed rock units and the potential mineralized zones. Thirty representative hand specimens were taken from the alteration zones and subjected to spectral analysis (ASD) and examined by Scanning electron microscope (SEM). The spectral reflectance of the minerals in the samples, which were taken from country rocks and altered and sheared zones, was measured using a hand-held spectrometer. The spectral reflectance characteristics of various wall rocks, altered rocks, and ores are highly beneficial for the explanation of remote sensing data and the remote sensing search for mineral deposits. Mineral percentages can be determined using scanning electron microscopy (SEM), morphology and relationships between phases, such as coating or erosion of crystals, can be observed. A thin section is created and the rear side is polished until there is no longer any surface texture. After that, they are carbon coated and prepared for analysis. In the study, the gold particles are primarily found in sulphides, malachite, and iron oxides, which are opaque minerals. Compared to quartz veins and country rocks, the presence of gold is found in significantly higher concentrations in sheared and altered zones.
The results of remote sensing approaches accompanied by data interpretation of gamma-ray spectrometry were strongly suggested as a tested and validated technique for locating prospective sites for gold mineralization. It would contribute to the long-term growth of the chosen area because the accepted approaches could be applied to similar goals in the future in those other locations.