GEOCHEMICAL CHARACTERIZATION OF RECENT SEDIMENTS IN THE BALTIC SEA BYBULK AND ELECTRON-MICROPROBE ANALYSIS

Nineteen samples of silty and clayey sediments of the Baltic Sea were analyzed by bulk methods (atomic absorption spectrometry and inductive ly coupled plasma optical emission spectrometry), as well as by electr on probe X-ray microanalysis (EPXMA). Processing of the EPXMA-data res ulted in nine different particle types which have been identified as d ifferent mineral species. Quartz and aluminosilicate particles am most abundant (often mom than 95%), although they am not of much help for the characterization of the geochemistry of Baltic sediments. Reductio n products, such as Fe-sulfides and rhodochrosite, are found in anoxic sediment environments (e.g. Gotland Deep). The oxides/hydroxides of i ron and manganese are more indicative of oxic environments (e.g. Katte gat). In regions with periodic changes in the redox conditions, oxides /hydroxides and sulfides are detected side by side (e.g. Lubeck Bight, Arkona Basin). The detected Ca- and Ti-rich particles show a geograph ical dependence. The Ca-rich particles are found in the transition reg ion between the Baltic Sea and the North Sea. Ti-rich particles have h igh abundances around the coastlines of Germany (e.g. Lubeck Bight) an d southern Poland. The results of the bulk analysis and of the individ ual particle analysis are often complementary.