A Comparative Study of Landsat-7 and Landsat-8 Data Using Image Processing Methods for Hydrothermal Alteration Mapping

摘要: Comparing spaceborne satellite images of Landsat-8 Operational Land Imager (OLI) and Landsat-7 Enhanced Thematic Mapper plus (ETM+) was undertaken to investigate the relative accuracy mapping hydrothermal alteration minerals. The study investigated northern part Rabor, which contains copper mineralization occurrences, is located in Kerman Cenozoic magmatic assemblage (KCMA), Iran. Image processing methods band ratio, principal component analysis (PCA), spectral angle mapper (SAM) were used map distribution hydrothermally altered rocks associated with porphyry mineralization. ratio combination both sensors for areas showed similar outcomes. PCA exposed variations spatial hydroxyl-bearing representation using OLI data more satisfactory than when ETM+ data. SAM found results zones. Verification came through ground investigation laboratory studies. Rock samples (n = 56) collected validate thin sections, X-ray diffraction (XRD) analyses. Field observations revealed that phyllic propylitic alterations dominate zones area. Argillic iron oxides/hydroxides observed a lesser degree. indicate maps prepared by visual interpretation are suitable those due higher radiometric resolution lower interference between vegetation areas. As bandwidth 7 covers absorption feature alteration, better achieved