Assessing the Mineral Alteration in Ambaji–Deri Region (Northwestern India) Using Hyperspectral Remote Sensing

We used Airborne Visible Infrared Imaging Spectrometer-Next Generation data for mapping possible mineral alterations, which aid in mineral exploration over larger areas. The data were subjected to various advanced processing techniques like Minimum Noise Fraction, Pixel Purity Index, N-Dimensional visualization and Spectral angle mapper classification. End-member spectra were matched with those of the minerals as available in the United States Geological Survey Spectral Library. In the present study, the Ambaji–Deri area of northwestern India was mapped for mineral alterations. The area has thick forest cover along with rugged topography, which warranted the use of hyperspectral remote sensing approach. The minerals such as calcite, muscovite and chlorite have been mapped, which are showing a good correlation with the ground geological records, barring epidote, whose distribution is scattered. We attribute the possible reason to be the spectral similarities between epidote and chlorite, which makes them difficult to differentiate only on the basis of the present hyperspectral study. The hyperspectral technique, as illustrated, provides powerful tool for mapping mineral alteration to mineral deposits. This enables scrutiny of a wider area of interest to being narrowed down for first-hand field investigations.