GEOCHEMISTRY OF RAJAPUR AND PUTTUR THERMAL SPRINGS OF THE WEST-COAST,INDIA

Thermal springs of Rajapur and Puttur (Irde and Banduru) are of low-te mperature and low-flow type. Though they are located at two different geological set up, they fall in Na-HCO3 facies. The imprints of basalt - thermal water interaction at Rajapur and local equilibration of dol eritic dyke with the thermal water of Irde is deduced. The reservoir o f the Rajapur thermal spring is likely to be located in the Precambria n formations,as that of Puttur thermal springs and hence the chemical processes undergoing in these systems are similar. The reservoir tempe ratures estimated using chemical geothermometers are about 200 degrees C and >120 degrees C for the Puttur and Rajapur thermal springs respe ctively. Illite, K-mica, chlorite, kaolinite, Ca-montmorillonite and p hilipsite are the expected secondary minerals in the system.