APPLICATIONS OF IMAGING SPECTROSCOPY FOR NON-METALLIC MINERAL EXPLORATION

Abstract. Imaging spectroscopy/hyperspectral remote sensing technique acquires images in a very narrow and contiguous spectral bands. High spectral resolution data provided by imaging spectrometers enables remote compositional mapping of earth surface. In the present study, we demonstrate the potentials of airborne AVIRIS-NG datasets for identification and mapping of non-metallic minerals. Several minerals such as carbonates, sulphates and phyllosilicate exhibit diagnostic absorption feature in Short Wave Infrared Region (SWIR) (2.0–2.5 μm). Therefore, mapping of wavelength of deepest absorption in SWIR is very useful for exploratory earth surface composition/mineral mapping. To map the mineralogical diversity in the parts of Banswara region, Rajasthan, wavelength of deepest absorption feature and absorption band depth in SWIR region was calculated at each pixel. It was found that majority of pixels showed absorption near ∼2.31, 2.33 and 2.20 μm. Detailed analysis of spectra of image revealed dolomite as dominant mineral at pixels showing deepest absorption at 2.31 μm. Calcite and clays were found to be present at pixels showing deepest absorption feature near 2.33 and 2.20 μm respectively. It is noted that mapping wavelength position of deepest feature is a very fast and reliable indicator of mineralogy. The mineral map of calcite and dolomite shall be useful for locating new mining prospect in the region.