Investigating porphyry copper alterations and spectral behavior of related minerals using ASTER satellite images in the Zafarghand region, Isfahan


1 Department of Mining Engineering, Amirkabir University of Technology (Tehran Polytechnic)

2 Iranian Space Research Center, Tehran, Iran



The purpose of this study is to highlight the alterations in the region using methods such as; False Color Composite (FCC), Band Ratio (BR), Least Square Fitting (LS-Fit), Matched Filtering (MF), Principal Component Analysis (PCA) and Spectral Angle Mapper (SAM) are also used to identify pure pixels. The region uses the PPI method, which takes advantage of the result of the Minimum Noise Fraction (MNF) method (7 methods in total). To validate the results, the alteration map of the region has been employed, based on which the results have a very high correspondence with the phyllic and propylitic variations in the study area. The processing methods applied to the area have highlighted the phyllic, argillic and propylitic alteration, but due to the limited potassic alteration in the Zafarghand area, the correct identification of this alteration in the area is not guaranteed. In terms of identifying and highlighting the alterations in the study area, SAM, PPI, BR, and PCA methods have been very effective, each of which helps to analyze spectral data or images and identify differences and different patterns in the study areas. In fact, with a more detailed look, it could be admitted that in highlighting the alterations in the Zafarghand region with the help of the aforementioned 7 processing methods, argillic changes with 71.43% accuracy (5 methods), phyllic changes with 85.71% accuracy (6 methods) and propylitic changes with 71.43% accuracy (5 methods) have been identified and approved.


Main Subjects