Abstract
Gossans (Fe-rich alteration zones) are the surface indications of massive sulfide, porphyry and skarn deposits in the Arabian Nubian Shield. They consist of limonite, goethite, hematite, malachite, and azurite. The Khunayqiyah gossans, Eastern Arabian Shield, Saudi Arabia, have been used to demonstrate the effectiveness of using the Landsat 8 OLI imagery for detecting and delineating of gossan zones in arid regions. The Khunayqiyah gossans have diagnostic spectral features, and they are often larger than the pixel size of the Landsat 8 OLI images. Remote sensing techniques in this study include pan sharpening, principal component analysis (PCA), minimum noise fraction (MNF), and band ratio. The RGB (red, green, blue) color composites of pan-sharpened original bands (4, 3, 2), PCA (PC3, PC2, PC1) and MNF (MNF2, MNF4, MNF3) images were found to be the most useful to delineate gossan/alteration zones in the Khunayqiyah district. The obtained results show reasonable matches between the spectra of collected samples and image-derived spectra from Landsat 8 data. Notably, the use of above-mentioned technique for mineral exploration is facilitated by the arid environment. The results of this study demonstrate Landsat 8 OLI images and the above-mentioned technique are useful in the exploration of new gossan occurrences in the Arabian Nubian Shield and other arid regions worldwide where little in situ geological data exist.