Wody w otoczeniu Jaskini Radochowskiej (Góry Złote, Sudety)

Abstract

Waters in the surrounding of the Radochowska Cave (Sudety, SW Poland).S u m m a r y. The presented paper concerns the geochemistry of spring waters in the crystalline mountain region of south-west Poland (fig. 1). The research group has mapped all surface waters existing in the 4 km2 study area. The resulting map (fig. 1) includes springs, wetlands and watercourses. Some points on the map represent entire spring zones (fig. 1: points 5, 11 and 13). The spring waters as well as waters from the Jaskiniec stream (fig. 1: point D ) were sampled and sent for laboratory chemical analysis (results are presented in Table 1). In addition, the waters of Radochowska Cave (fig. 2) were also sampled (at points 20 and 21). The physical, field parameters of the investigated waters were checked in the field. The chemical analyses of the 11 samples (8 spring water samples, 2 consisted of cave water samples and 1 water sample from the Jaskiniec stream) divided our samples to two groups (Table 1). The first group were slightly mineralized (M 100 mg/L) waters, strongly dominated by sulfate anions. Their cation composition showed magnesium and calcium are in similar equivalent concentrations (fig. 3). The waters are slightly acidic (pH 5,55– 6,76). This water type was named the „sulfate waters” (springs 1, 5a, 5b, 13a, 13b i 19). The second group, „bicarbonate waters” were higher mineralized (over 200 mg/L), strongly dominated by bicarbonates and calcium (fig. 3), and with a neutral pH. Waters from the springs 11a and 11b and the sampled cave waters were of this type. The chemical compositions of the investigated sulfate and bicarbonate waters are very different when considering equivalent proportions (fig. 4). However, in terms of absolute values (mg/L), only the calcium and bicarbonates concentrations differentiate the types (Table 1). All the other ions have similar concentrations in both types of waters (including sulfate). As shown in figure 5, the bicarbonate waters of the investigated area are always related to local marble outcrops. We believe that the sulfate waters, acidic and slightly mineralized, migrate down the natural groundwater flow gradient and then penetrate the marble lens. This aggressive water then dissolves the carbonates, and saturates with the products of this solution process: bicarbonates and calcium. The study of the chemical compositions of the spring and cave waters resulted in an understanding of the water circulation system in the entire rock massif. Until now, it was reported that spring waters in hard rocks of the mountainous areas of the Sudety resulted from very shallow and low residence circulating waters. If this were the case, the various waters chemical types would not be representative of the host rock mineralogy.