Chemizm wód porowych morskich iłów trzeciorzędowych występujących na terenie Polski i NRD

Abstract

Przeanalizowano wpływ ciśnienia na skład chemiczny wód porowych wydzielanych z utworów ilastych. Ustalono optymalną metodykę wydzielania tych wód z morskich iłów trzeciorzędowych. Przedstawiono wyniki badań chemizmu wód porowych iłów krakowieckich z rejonu Osiek–Baranów (Polska) oraz iłów rupelu z Vehlitz koło Magdeburga (NRD).  CUEMISTRY OF PORE WATERS OF MARINE TERTIARY CLAYS IN POLAND AND GDR The paper presents results of studies on pore water of marine tertiary clays from Poland (Sarmatian Krakowiec Clays) and GDR (Middle Oligocene – Rupelian Clays). The studies, carried out in the last years, showed that the interpretation of results of analyses of chemistry of pore waters will not be satisfactory unless the methods of pore water extraction are appropriately chosen for a given rock type. In the case of the studied clay deposits (see Table I for their mineral composition) it was found that most homogeneous pore waters are obtained when the applied pressures not exceed 12,000 N/cm2.The analysis of results of studies on chemistry of pore water extracted from the Krakowiec Clays (Fig. 2) showed that three series recognized with reference to macroscopic observations and analyses of physical properties – the top, middle and basal series – differ in both mineralization and chemical composition of the pore water. The mineralization was found to increase generally along with depth, similarly as chemical composition of the water (Table 2). Waters of the SO4-HCO3-Na type occur in the top series, those of the SO4-CI-Na type in the middle, and those of the Cl-SO4-Na type in the basal.The Rupelian clays also display changes in mineralization and chemical composition of pore waters along with depth (Fig. 3). The results of studies on chemistry of pore waters from the Krakowiec (Fig. 2) and Rupelian (Fig. 3) clays indicate differences in hydrochemical conditions in time of sedimentation of these deposits. The results obtained also cast some light on processes responsible for alteration of pore waters, especially of those occurring in subsurface zone.