Hydrogeochemistry of the Thermal Springs of Pojqpoquella and Phutina, Puno, Peru

Abstract

Abstract This paper deals with the results of a hydrogeochemical study of two thermal springs that originate from in very high altitudes in southwestern Peru with outflow temperatures of maximal 38,4 °C and flow rates of 1.08 - 2.02 l/s. Water samples from the Pojqpoquella and Phutina geothermal wells, were collected during the period between September 2018 and January 2019 in the main area of Puno. Chemical types of the thermal spring are Na+, Ca2+, Cl- and CO 3 2 − in Ayaviri and Putina. According to the Piper and Schoeller diagrams for the Pojqpoquella thermal spring water is classified as Na++ K+ (75 %) and Cl- (60 %) type water while that of the Phutina thermal spring is classified as Na++ K+ (76 %) and Cl- (72 %) type water. The electrical conductivity (EC) values for the Pojqpoquella and Phutina thermal spring waters is 2160 - 3142 μS/cm and 3160 - 3184 μS/cm, respectively, the thermal spring waters have a high electrical conductivity which shows that it has interacted with the host rock for a long time. The reservoir rocks of the Pojqpoquella thermal system consist of a red sandstones and conglomerate rocks while the reservoir rocks of the Phutina thermal system consist of a thick sequence of cretaceous rocks.