Abstract

This investigation used Earth Observing-1 (EO-1) ALI (advanced land imager) and hyperion data to extract the geological and mineralogical information for identifying hydrothermal alteration zones associated with porphyry copper deposits in southeastern segment of the Central Iranian Volcanic Belt, SE Iran. A band ratio derived from image spectra (4/2, 8/9, 3 in RGB) has been developed to identify lithological units and hydrothermally altered rocks using ALI data in a regional scale. Analytical imaging and geophysics (AIG)-Developed Hyperspectral Analysis processing methods were tested on the shortwave infrared bands of hyperion for mapping mineral assemblages in hydrothermal alteration zones associated with two known copper ore deposits, namely Sar Cheshmeh and Meiduk. The methods produced image map of spectrally predominant minerals in alteration zones using hyperion data. Therefore, phyllic, argillic, and propylitic alteration zones were significantly discriminated from surrounding country rock. The spatial distribution of identified hydrothermal alteration zones has been confirmed by spectral reflectance measurements, XRD analysis and in-situ inspection. The research presented here indicated that lithological units,  hydrothermally altered rocks, and hydrothermal alteration zones associated with porphyry copper mineralization can be accurately mapped by ALI and hyperion data at both regional and district scales.

Key words: Advanced land imager (ALI), hyperion, analytical imaging and geophysics (AIG)-developed hyperspectral analysis processing methods, Central Iranian Volcanic Belt.