Identification of new base metal mineralization in Kumaon Himalaya, India, using hyperspectral remote sensing and hydrothermal alteration

Economic mineral deposits are commonly associated with zones of intense hydrothermal alteration. Space borne hyperspectral remote sensing is one of the recent techniques that enable the identification of hydrothermally altered and weathered minerals. In this study, we identified hydrothermally altered and weathered minerals of a gossanised outcrop rich in base metal mineralization in parts of the Kumaon Himalaya, India using an EO-1 Hyperion (hyperspectral) satellite data. Spectral Angle Mapper classification method was used to map the different altered/weathered minerals within the study area. The method identified the occurrence of dolomite and dolomite with chlorite minerals from the Hyperion data. The finding was verified in the field and confirmed through laboratory analyses. Representative samples measured for spectral absorption characters, reflected and transmitted petrography, X-ray diffraction and ICP-MS analyses confirmed the occurrence of Ag, Cu, Fe, Pb, Zn, As, and Sb base metal rich elements in the Thalkedar limestone. Our study recommends the technique to the map base metals and hydrothermally altered minerals in the other parts of Thalkedar limestone of Kumaon Himalaya and similar region of the world. The study is an important case for formulating exploration strategies in terrenes with rugged topography and dense vegetation.