Implication of epithermal mineralization as proxy for geothermal energy potentiality in Puga, Ladakh UT, India

Abstract The present study area, Puga, is located along the inflexion point of Indian and Asian plates comprising of zone of anatectic melting, where thermal activity is attributed to the extensive igneous activity during Upper Cretaceous to late Tertiary age. The area is characterized by geysers, past fumaroles, steaming grounds and mud pools with vast spread of sulfur, carbonates and borax deposits with surface temperature of hot springs of 84°C, which is the boiling point of water at ~ 4500 m above mean sea level. It is the only known geothermal system where rare alkali enrichment in thermal fluids follows the sequence: Cs > Li > Rb. Our study shows for the first-time evidence of lithium containing mica mineral, polylithionite, in the thermal spring deposits. The study also shows occurrence of epithermal minerals like jarosite, thenardite, alunite, tincalconite in the hot spring deposits with reservoir temperature estimated from multiple ion exchange geothermometers of ~250°C. Therefore, this study presents a state-of-art approach demonstrating that the presence of hydrothermal minerals within surface hot spring deposits can act as a promising indicator for identifying shallow high-temperature zones in the reservoir.