Porphyry deposits are typically associated with specific hydrother- mal alteration zones. The identification of hydrothermal alteration patterns in porphyry deposits using remote sensing imagery is a cost-effective tool to identify zones of high potential zones. The West Zafarghand porphyry is located in the northeast of Isfahan, central part of the Cenozoic Urumieh-Dokhtar magmatic arc. Lack of interpretation of the spatial pattern of hydrothermal alteration zones and their relationships to ore mineralisation in the study area has led us to use ASTER remote sensing data to detect alteration patterns. Delineating the extent of hydrothermal alteration zones and high-grade mineralised lithological units is a particular goal of this study. We used various image processing techniques such as False Color Composite, Band Ratio, Principal Component Analysis, Minimum Noise Fraction and Spectral Angle Mapper. Remote sen- sing results, field observations, petrographic surveys and XRD revealed argillic, phyllic and propylitic hydrothermal alteration zones in the central part of the study area. An overall accuracy of 90% and a kappa coefficient of 0.84 were achieved in this analysis. The spatial distribution of the NE-SW trending phyllic alteration zone discovered in this study could be considered an area of high potential for a comprehensive exploration campaign at this deposit.

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