Jednostka hydrogeologiczna szczaw Gór Izerskich

Abstract

Omówiono skład chemiczny oraz miejsca wypływu szczaw z czterech punktów w Górach lzerskich. Wykazano, że wody te w poszczeg6lnych miejscowościach stanowią różny stan metamorfizacji oraz mieszają się z płytkimi wodami radoczynnymi dając szczawy radoczynne. OkreśIono przypuszczalny obszar zasilania i drogi krążenia szczaw oraz scharakteryzowano wody radoczynne.

HYDRO GEOLOGICAL UNIT OF THE GORY IZERSKIE CARBON DIOXIDE WATERS

Carbon dioxide and radon waters occurring in the Góry lzerskie Mts, western part of the Sudety Mts, are used for medical purposes in Świeradów-Zdrój and Czerniawa-Zdrój health resorts in Poland and Lázně Libverda in Czechoslovakia.

The waters flow out within or in direct neighborhood of a belt of micaceous schists, 0.5 to 1.5 km wide and about 30 km long. The schists and surrounding gneisses are dipping northwards at the angle of 50 - 70° (Fig. 1) and they display two types of dislocations: older, E - Wand SW - NE oriented, and younger, NNE - SSW oriented.

Carbon dioxide waters occurring in the above area are characterized by total mineralization up to 0.3% and the type HCO₃-Ca-Mg+(Fe)+(F)+(Rn), and the radon waters - by mineralization over 0.005% and the type (HCO₃)-(SO₄)-(Ca)-(Na) and content of radon up to nCi/dm³. Figure 2 shows location of intakes of these waters in Polish health resorts.

The data concerning chemical composition of waters from the Góry lzerskie Mts were plotted in the graph (Fig. 3). Taking into account waters with the highest mineralization in individual localities ("pure" carbon dioxide waters), we obtain a series of chemical compositions (lines 1-4), representing different stages in metamorphism of certain waters. At the same time, the "pure" carbon dioxide waters mix up with shallower-seated ones in all the localities, which leads to origin of waters with intermediate chemical composition. Both cases overlap one another in the graph.

The content of juvenile CO₂ in carbon dioxide waters ranges from t 500 to 3500 mg/dm³.

The chemical type of carbon dioxide waters should be regarded as related to water circulation in micaceous schists and drainage of neighboring gneisses. The area of supply of carbon dioxide waters, situated south of their outflows, is built of gneisses. Waters circulating for several decades descend to depths of about 2,000 - 3,000 m. In the course of migration to places of outflow, they mix up with radon ones, which leads to origin of radon-bearing carbon-dioxide waters. Figure 4 shows the scheme of hydro-geological structure of the lzera carbon dioxide waters.