Mapping of surface hydrothermal mineral alterations and geological structures related to geothermal systems in the Songwe region, SW Tanzania

Abstract

Geothermal energy is one of the most valuable and preferable renewable energy sources, given that it produces sustainable, dependable, and clean energy. Understanding the geothermal systems, parameters such as heat, fluids, and structures help to identify potential geothermal systems. These parameters are manifested as hot springs, fumaroles, and alteration minerals. Hydrothermal alteration minerals are often used in geothermal system exploration to evaluate factors such as temperature, fluid, and structures. This study employed GIS and remote sensing in the investigation of hydrothermal mineral alterations and delineating geological structures which provided invaluable information for identifying prospective geothermal resource zones. ASTER was utilised to map phyllic, argillic, and propylitic minerals using SPCA, whereas ISO cluster classification was used to detect kaolinite, smectite, calcite, chlorite, and muscovite/illite-rich areas. DEM was used to extract and map geological lineaments. Results have revealed that the regions that were mapped with indicator hydrothermal alteration minerals were also associated with geological structures. The field work, XRD, and ASD laboratory analysis results indicated a good match with the findings from the remote sensing data. The approach applied in this study may be used along with other techniques during the early phases of geothermal exploration to define geothermal potential targets.