Charakterystyka hydrochemiczna wód podziemnych południowego skrzydła niecki Podhala
Abstract
HYDROCHEMICAL CHARACTERISTICS OF GROUNDWATER IN SOUTHERN LIMB OF THE PODHALE BASIN Summary Some problems connected with formation of physico-chemical composition of groundwater in the contact zone of the Tatra Mts series and Podhale Fysch rocks were analysed with the reference to the results of stationary and seasonal studies carried out by the author and of deep drillings made by the Geological Institute. The analysis has shown a decisive influence of the location of alimentary area and the nature of migration routes on the type of water. Despite of differences in the style of geological structure, morphology and climatic conditions in the Tatra massif and the Podhale Basin in its forefield, groundwaters of this region have several features in common, determined by a hydraulic connections between fissure-karst water of the above mentioned lithological-structural units and pore water of the Quaternary cover. The interrelations are exceptionally clear in areas where moraine, fluvioglacial or alluvial sediments rest directly on permeable older bedrock. When this is the case, groundwaters from the Quaternary cover may migrate downwards, sometimes to the depth of 1500 m, through systems of fissures and fractures as well as karst caverns. The predestined zones for migration of the waters are the zones of tectonic discontinuities transversally cutting the margin of the Tatra Mts. The chemistry of groundwaters occurring in the subsurface zone and those of deeper-seated aquifers was analysed separately. In the subsurface zone, water table is free, following the terrain morphology and it is rapidly responding to climate factors. These are fresh waters, ultrafresh in the Tatra Mts, with predominance of bicarbonates and calcium and varying relations of sulfates, magnesium and sodium. Generally deeper-seated aquifers may be assigned to two stages: upper, with ionic composition close to that of the subsurface zone groundwaters, somewhat higher mineralization and higher contribution of H2S. Water temperature is the function of depth of water intake - lower, characterized by occurrence of mineral waters with negligible content of hydrocarbons and chlorines, the content of SO4 ion over 90% (Fig. 5), and the lack of H2S. It was also found that waters of the upper aquifer stage, although meteoric in origin, are characterized by fairly stable chemical composition and thermal relations. This is the most important aquifer horizon, stretching along the northern margin of the Tatra Mts.Downloads
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Geochemia, mineralogia, petrologia
