Integration and analysis of airborne geophysical and ETM+ data for exploration of porphyry type deposits in the Central Iranian Volcanic Belt using fuzzy classification

Abstract

Previous studies have shown that there are altered areas that do not show anomalies in geophysical data but anomalies can be seen in processed Thematic Mapper images and vice versa. In order to map the altered areas associated with porphyry type copper deposits, the airborne geophysical data, i.e. radiometry and magnetometry and Landsat Enhanced Thematic Mapper (ETM+) data (hydroxyle and iron oxide images) of an area located in the Central Iranian Volcanic Belt have been integrated and analysed using fuzzy classification. Sar Cheshmeh and Darrehzar areas with known mineralization and alteration were chosen as training areas. After defining the training areas (Sar Cheshmeh and Darrehzar), the entire region was classified into altered and unaltered areas. Field observation and sampling confirmed a high classification accuracy. This analysis was found to be useful for exploration of porphyry type deposits in the Central Iranian Volcanic-Sedimentary Belt, where most parts of this belt are surveyed using airborne geophysics.