Hydrochemistry and geothermometry of the thermal waters of the Benitez Municipality of Sucre state, Venezuela

Abstract

The thermal waters are a resource that, in addition to increasing tourism, is used for the production of electric power. Twenty hot springs of the Benitez municipality were evaluated, to know their hydrochemistry and to estimate the temperature of the reservoirs, through the use of geothermometers, which use the chemical composition of the water that emerges. In the selected sources, “in situ” measurements were taken and water samples were taken at the point of emergence for further chemical analysis. The temperatures of the waters were between 29.5 and 92.7 ° C, considering that, in the area are sources with hypothermal, mesothermal and hyperthermal characteristics. The pH values ranged from acid (2.0) to neutrality (6.8), with conductivity values (785 - 14455 pS / cm) and total dissolved solids (0.29 - 2.65 g / l) , that identify them as waters with an appreciable mineralization. Among the major ions, the presence of Na + (up to 866 mg / l) and Cl- (up to 1602 mg / l) predominates. The predominant sequence among the cations was Na +> K +> Ca2 +> Mg2 + and between the anions was Cl “> SO42”> HCO3. “The minority ions, for the most part, 
are below 1 mg / l. The presence of the stable isotopes oxygen-18 (18O) and deuterium (2H), show that they are water due to evaporation.The estimated temperatures, with different Na / K geothermometers, oscillated between 197 and 937 ° C. The studied waters can potentially be used as sources of electrical energy, in addition to recreational and leisure purposes that promote the economic and social development of the sectors where they emerge.