Fusing ASTER, ALI and Hyperion data for enhanced mineral mapping

This investigation fused Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Advanced Land Imager (ALI) and Hyperion data for detecting hydrothermal alteration minerals associated with porphyry copper mineralisation and related host-rock lithology. The distribution of iron oxide/hydroxide minerals, vegetation and clay minerals was identified based on principal component analysis, using the distinctive bands of ASTER and ALI at a regional scale. The analysis also showed that by fusing these different data sources, the discrimination of quartz- rich igneous rocks from the magmatic bedrock and the boundary between igneous and sedimentary rocks using ASTER thermal infrared bands could be made. An image map of spectrally predominant mineral assemblages in the hydrothermal alteration zones could be produced using the shortwave infrared bands of Hyperion data at a district scale. Phyllic, advanced argillic and propylitic alteration zones associated with porphyry copper mineralisation were discriminated based on the identified alteration minerals such as sericite, kaolinite, illite, alunite, chlorite, epidote and calcite. Results have proven to be effective, and in accordance with the results of field investigations. It is concluded that the methods of image and data fusion of spectral information derived from ASTER, ALI and Hyperion data can produce comprehensive and accurate information for copper resource investigations.