WSTĘPNE WYNIKI BADAŃ SKŁADU MINERALNEGO KREDY JEZIORNEJ I GYTII W ŚWIETLE NOWOCZESNYCH METOD BADAWCZYCH

Abstract

PRELIMINARY RESULTS OF THE MINERAL COMPOSITION OF LACUSTRINE CHALK AND GYTTJA IN RELATION TO MODERN INVESTIGATION METHODS

Abstract. Lacustrine chalk and gyttja are carbonate freshwater sediments, applied in agriculture as an addition to feeds and for liming acidic soils. In Poland, they occur mainly in its northeastern part; in the regions involved in the last glacial maximum. The main compounds are calcite and organic matter, which originate from various types of plants. Besides the classical methods (e.g. derivatographic analysis), modern analytical techniques, i.e. electron microprobe analysis (EMPA), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were also used to determine the mineral composition. The investigated samples were collected from the localities of Tarda (Iława lake district) and Suliszewo (Choszczno lake district). The purpose of the study was to determine the qualitative mineral composition of both the sediments, as well as the mode of generation of each compound. The analysis shows that the lacustrine chalk and gyttja reveal a biphasic structure and consist of two equal phases: a liquid phase which stands as mineralised water; and a constant phase, in which calcite and organic matter are the major components. The constant compounds of the sediments can be divided into three groups: main compounds (calcite, fitogenic organic matter) and subsidiary autogenic compounds (pyrite), subsidiary allogenic compounds (quartz, feldspars, clay minerals, micas, glauconite and epidote).