Per-pixel and sub-pixel mapping of alteration minerals associated with geothermal systems using ASTER SWIR data

This paper is focused on assessing the applicability of the Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) shortwave infrared data in proxy mapping of subtle geothermal (GT) systems by identifying hydrothermally altered indicator minerals. The study was carried out at Yankari Park NE Nigeria. Spectral mapping is applied on ASTER data using perpixel and subpixel algorithms to extract and discriminate associated altered areas of interest. Field checks and altered rock sampling was done using GPS around the Wikki and Mawulgo thermal springs to validate results. Sampling points were used as training sites for image spectral analysis. X-Ray Diffraction results shows presence of kaolinite, quartz, hematite and dickite. This investigation demonstrates the utility of alteration mapping as a tool for GT resource exploration in uncharted regions.