Characterizing hydrothermal alteration zones in Hamama area in the central Eastern Desert of Egypt by remotely sensed data

摘要

Remote sensing techniques provide meaningful information to mineral exploration by identifying the hydrothermally altered minerals and the fracture/fault systems. In this article, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data were processed to detect the hydrothermal alteration zones in Hamama area in the central part of the Eastern Desert of Egypt. Band ratios and principal component analyses successfully revealed the extent and the geometry of the hydrothermal alteration zones that trend in an NE-SW direction. Matching pixel spectrum derived from Minimum Noise Fraction, Pixel Purity Index, and n-dimensional visualization with reference spectra allowed characterizing key hydrothermal alteration minerals, including chlorite, kaolinite-smectite, muscovite, and haematite, in a successive alteration pattern. Field investigations and X-Ray Diffraction analysis validated the results revealed by ASTER data. In addition, the present prospects of significant gold and massive sulphide mineralizations are consistent with the detected hydrothermal alteration zone.