German jako wskaźnik warunków hydrogeochemicznych w jeleniogórskim systemie geotermalnym

Abstract

Germanium as an indicator of hydrogeochemical conditions in the Jelenia Góra Geothermal System.A b s t r a c t . Geochemical studies on trace elements in thermal waters from Cieplice, Karpniki and Staniszów (Jelenia Góra Geothermal System, Sudetes, Poland) revealed a presumably regional relation between germanium and silicon. The Ge : Si ratios in waters of Cieplice are likely controlled by the chemical equilibrium process of silicate minerals transformation in granite aquifer-rocks. Geochemical inverse mass balance modelling using main rock-forming minerals of actual composition shows that incongruent dissolution of primary silicate minerals with forming secondary (clay minerals, silica forms) phases is responsible for thermal water chemistry in Cieplice. Available data on germanium in silicate minerals combined with the results of geochemical modelling give Ge : Si ratios close to real values. A chemical non-equilibrium, and a gradual decrease of both the germanium content and the Ge:Si ratio have been identified in the thermal waters from two new intakes (Karpniki, Staniszów).