Comparing the Performance of ASTER and LANDSAT 8 Satellite Images in Identifying Iron Oxide and Porphyry Copper Alterations in Zafarghand Region of Isfahan Province

Separation and mapping of alteration zones is of special importance in the exploration of porphyry copper types. In order to highlight these alteration zones, remote sensing techniques have been applied. Zafarghand region is located in the southeast of Ardestan and northeast of Isfahan. Based on the division of geological structural zones, it is located in the Central Iran zone and also in the middle part of Urmia-Dokhtar magmatic volcanic arc. In this area, there are different alteration halos, including phyllic, potassic, propylitic, argillic, and slightly siliceous. In this study, argillic, phyllic, propylitic, and clay alterations have been identified using ASTER sensor images. Moreover, LANDSAT 8 images have been employed to identify clay and iron oxide alterations. In this regard, after performing the necessary pre-processing, methods of False Color Combination (FCC), Band Ratio (BR), Least Squares-Fit (LS-Fit), Matched Filtering (MF), and Principal Combination Analysis (PCA) were applied to reveal the zones containing these alterations. Among the applied methods, the LS-Fit and MF in Aster images, as well as the BR method in both images, and the PCA method in Landsat 8 have brought good results.