Isotopic characteristics of a few selected structurally controlled geothermal systems of the Western Ghats,India

The Western Ghats is the most potential area of India in terms of geothermal energy exploitation and they are characterized by numerous faults. These faults acts as conduit for the deeper circulation of the geothermal water of meteoric origin and are controlling the geothermal systems of this region. The stable isotopic composition (δ¹⁸O and δ²H) of a few selected geothermal springs and non-thermal groundwater were monitored to identify their recharge sources. Tritium in geothermal water and groundwater were also measured to evaluate their transit time and the mixing processes governing within the geothermal systems. The temperature of hot springs varies from 56 to 71 °C. The stable isotope result shows that geothermal springs have absence of magmatic component and rainwater is their recharge source. It was also established that geothermal water has not undergone much fractionation because of rock–water interaction. Tritium content of the geothermal springs are low indicate deeper circulation and longer residence time of the thermal water. Lower tritium also shows insignificant mixing with non-thermal ground water.