Isotope Temperature Indicators of Thermal Waters in Western Poland

Abstract

Thermal springs occur or have occurred in the past in crystalline formations of the Sudetes Mountains. At all these sites, water was used for centuries as a therapeutic factor. In order to increase its temperature and available resources, boreholes up to 2000 m deep were carried out and the results are promising. However, in order to substantiate further drilling, temperatures in the deeper parts of particular hydrogeothermal systems have to be estimated. The paper presents the preliminary results of the application of SO4-H2O isotope geothermometer to three separate hydrogeothernal systems of Sudetes Mountains, namely: Duszniki, Ladek and Cieplice, where spring water temperatures range between 20 - 45oC. It was found that equilibrium was reached only in waters at Cieplice in the reservoir temperature of about 100oC. Such equilibria don't exist in thermal waters at Duszniki and L?dek, where secondary processes take place as for example, the mixing with shallow groundwaters, oxygen isotope shift due to very high CO2/H2O ratio (Duszniki), and reduction of sulfates (L?dek).