Aeromagnetic and Landsat-8 data interpretation for structural and hydrothermal alteration mapping along the Central and Southern Eastern Desert boundary, Egypt

Abstract

Pan-African basement rocks cover the study area along the boundary between Central and Southern Eastern Desert with small exposed sedimentary sequences. Several vein-type gold mineralization with hydrothermal alteration zones have long been known in the study area. Aeromagnetic and remote sensing imagery data were integrated for mapping the structural elements and hydrothermal alteration zones related to gold mineralization. By aeromagnetic imagery inspection, the structural complexity and porphyry intrusions density maps have been effectively constructed by applying Enhanced Center for Exploration Targeting (CET) techniques. Major NW shear zones along with NNW-SSE, WNW-ESE, NS, and NE-SW are the main trends controlling gold mineralization. On the other hand, applying band ratios and constrained energy minimization (CEM) technique on Landsat-8 data pointed out alteration minerals associated with the hydrothermal fluids. Calcite, sericite, and chlorite are the common alteration minerals detected, while goethite and epidote are less common in alteration zones of the area under study. A combination of CET structural complexity, circular features, and alteration zones produced a potential mineralization map pointing out numerous prospective zones for mineralizing gold. The predictive map was validated by projecting the known gold prospects at the study area, reflecting an agreement between the known gold occurrences and the higher classes of the predictive zone. The discussed techniques in the current research can be adopted as a direct indicator for structural mapping and detecting the alteration zones related to gold mineralization elsewhere.