Integration of ASTER and Landsat TM satellite data for lithological mapping and chromite prospecting

Landsat Thematic Mapper and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite data were used for lithological mapping and chromite prospecting in Neyriz ophiolitic zone in the south of Iran. Image transformation techniques, namely decorrelation stretch, band ratio, principal component analysis (PCA) were applied to the datasets. The RGB decorrelated image of Landsat TM bands 7, 5 and 4, and the principal components images of ASTER bands in the visible near infrared (VNIR) and shortwave infrared (SWIR) portions demonstrated the occurrence of major lithological units in the study area. The developed band ratios on the VNIR-SWIR spectral bands of ASTER, including 5/3, 5/1, 7/5 discriminated all rock units distinctly and delineated the host rock of chromite mineralized zone along the transition zone in the study area. Image processing results were verified by laboratory analysis and fieldwork. Result of this investigation indicate that the integration of Landsat TM and ASTER datasets is one of the most effective tool for lithological mapping and chromite prospecting in mountainous and inaccessible regions such Iranian ophiolitic zones.