الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Field and mineralogical studies are integrated with multispectral and radar satellite data to unravel the occurrence of sulfide dissemination in the Gabal Monqul area (Eastern Desert, Egypt). This study was motivated by the firm belief that this area’s widespread hydrothermal alteration haloes and sulfide disseminations were ambiguously deciphered as a porphyry-style mineralization. NE-Elongate bodies of silicified and sulfidized rocks frequently occur at the contacts between dacite (Dokhan volcanics), granodiorite, and porphyritic biotite granite intrusions. The structural control of the sulfidized rocks is presumed based on their tabular morphologies as well as the widespread NE-SW quartz and iron oxide veins. Band rationing of Landsat-8 OLI-band ratio (R:7/6, G:7/3, B:1/5) and ASTER Maximum Likelihood Classifier (MLC) provided an ease discrimination mean for the different lithological units in the study area and yielded high overall accuracy and Kappa coefficient values of 94.65 % and 0.93, respectively. Hydrothermal alteration zones are best identified and outlined by using band rationing (BR) and independent component analysis (ICA) techniques that help to distinguish between ferric and ferrous iron minerals. When fused with the clay and OH-bearing minerals maps, ferric iron oxides may characterize epithermal and porphyry mineralization in which ore formation occurs under oxidizing conditions. Iron-hydroxide (goethite), copper hydro-carbonate (malachite), and hydrous copper phosphate (pseudomalachite) are supergene mineral phases. The resultant processed images show that alteration extends beyond unit boundaries and overlaps different crosscutting lithologies. This observation implies that hydrothermal alteration of the host rock represents a secondary overprint. Additionally, gypsum (±anhydrite) and barite in association with iron oxides and pyrite disseminations pinpoint a porphyryii related alteration assemblage. The poor metal endowment in the potassic alteration zones together with the lack of hydrothermal breccia bodies argue against the supergene enrichment typical of the porphyry mineralization system and imply a rather epithermal sulfidation genesis. However, a thorough assay program is required to outline the potential metal-rich lithological unit (s) using XRD and remote sensing investigations that point to zonal alteration anomalies.