| Title | Hydrogeochemistry of Thermal and Cold Springs of Pranhita-Godavari Basin, India |
|---|---|
| Authors | Hemant K. SINGH, B. MAHATO, D. CHANDRASEKHARAM, Satish K. SINHA |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | Hydrogeochemistry, thermal springs, cold springs, Godavari Basin, India |
| Abstract | Based on the geological occurrences of the thermal springs, seven geothermal provinces have been identified in India. Godavari geothermal province is in Pranhita-Godavari basin of the Eastern Ghats-mobile belt and its thermal springs are enriched in Ca-SO4-HCO3. In this study, we analyze the physiochemical behavior of these thermal waters. Representative water samples were collected from several thermal and cold springs located along both sides of the Godavari River. Rock samples of the gneissic basement and surface sandstone were collected for water-rock interaction study and to understand the evolutionary history of the thermal and cold springs in the area. While the thermal springs of the study area are dominated by Ca-SO4-HCO3 rich water, the cold springs are Ca-HCO3 enriched. While some of the surface and groundwater samples collected from near the Bugga, Manuguru, and Ramagundam thermal springs show their typical Ca-HCO3 enrichment, others are SO4-Cl enriched. Likely, this is due to the interaction of water with the pyrite-bearing Gondwana formation and gneissic basement rocks. Enrichment of calcium, magnesium, and enhanced HCO3/Cl ratio in the thermal springs may have been caused by exchange and/or mixing process during water-rock interaction at an elevated temperature while ascending to the surface. This behavior of water is also observed during the water-rock experimental studies at 100 °C. As a result, thermal springs show shifting towards the bicarbonate field in the piper trilinear diagram. Based on the chemical-geothermometry, the estimated reservoir temperature ranges from 80 to 174 °C. |