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The present paper discusses the influence of geochemical properties on biogenic deposits in the Wilkostowo mire near Toruń, central Poland. The analysed core has allowed the documentation of environmental changes between the older part of the Atlantic Period and the present day (probably interrupted at the turn of the Meso- and Neoholocene). In order to reconstruct the main stages in the sedimentation of biogenic deposits, we have used stratigraphic variability of selected litho-geochemical elements (organic matter, calcium carbonate, biogenic and terrigenous silica, macro- and micro-elements: Na, K, Mg, Ca, Fe, Mn, Cu, Zn, Pb, Cr and Ni). The main litho-geochemical component is CaCO3; its content ranges from 4.1 per cent to 92 per cent. The variability of CaCO3 content reflects mainly changes in hydrological and geomorphological conditions within the catchment area. The effects of prehistoric anthropogenic activities in the catchment of the River Tążyna, e.g., the use of saline water for economic purposes, are recorded in a change from calcareous gyttja into detritus-calcareous gyttja sedimentation and an increased content of lithophilous elements (Na, K, Mg and Ni) in the sediments. Principal component analysis (PCA) has enabled the distinction the most important factors that affected the chemical composition of sediments at the Wilkostowo site, i.e., mechanical and chemical denudation processes in the catchment, changes in redox conditions, bioaccumulation of selected elements and human activity. Sediments of the Wilkostowo mire are located in the direct vicinity of an archaeological site, where traces of intensive settlement dating back to the Neolithic have been documented. The settlement phase is recorded both in lithology and geochemical properties of biogenic deposits which fill the reservoir formed at the bottom of the Parchania Canal Valley.

The mercury content in peat layers of seven peat bogs in the Małopolska region (Wolbrom in the Kraków-Częstochowa Upland and Otrębowskie Brzegi, Puścizna Wysoka, Puścizna Mała, Przybojec, Puścizna Długopole and Bór na Czerwonem in the Orawa-Nowy Targ Basin) was determined to a depth of 100 cm at a resolution of 1–2 cm. Geochemical background and level of anthropogenic mercury enrichment were determined for each peat bog. To establish the interdependence between mercury concentration, mineral matter content and selected metals, geochemical diagrams and models of the system were drawn up representing the correlational relationships between the selected geochemical variables for three of the peat bogs in the Orawa--Nowy Targ Basin (Otrębowskie Brzegi, Przybojec and Bór na Czerwonem). It was found that, comparing against other European raised bogs, the range of mercury concentrations in the peat layer down to 50 cm in the peatlands of Małopolska is similar to those in Norway, Sweden, Denmark and Spain, and decidedly lower than in the peatlands in Scotland, Belgium and Czechia. Furthermore, the sites in the Orawa-Nowy Targ Basin were clearly lower, the lower the altitude of the peat bog surface, which is probably associated with local topoclimatic conditions. [ABSTRACT FROM AUTHOR]

The subject of the work is a reconstruction of environmental conditions in the Lower Oder River Valley in the early Middle Ages with use multi-proxy research. This was considered in terms of natural determinants of the development of hydrogenic habitats in the estuary section of a large lowland river, but at the beginning of a headland of natural morainic plateau known as Castle Hill in Szczecin. In a relatively small area, three different types of geochemical landscapes were distinguished that had specific functions in matter cycles, including the water cycle. The article mainly presents the results of geochemical studies for a series of biogenic deposits separated by a series of lacustrine sediments with a large admixture of mineral material. An attempt was also made to determine subfossil animal remains in the sediments. [ABSTRACT FROM AUTHOR]

The results of geochemical assays on biogenic sediments filling a fossil lacustrine basin at Wąwelnica, in the Szczecin Hills, within the left-bank part of the Oder River catchment are presented. The data reveal a natural Holocene sedimentation sequence similar to that found for other sites in central Europe. The geochemical record of palaeo-environmental changes, which may be a consequence of human activities in the proximity of the site, is distinctly bipartite. The part of the profile corresponding to the lacustrine sediment accumulation during the Greenlandian occasionally shows an increased mineral content and an elevated catchment erosion index. An incidental presence of Palaeolithic and Mesolithic communities is confirmed by archaeological evidence from a few sites in the Szczecin Hills. More distinct episodes of mineral matter supply and more pronounced changes in geochemical indicators can be inferred as occurring from the onset of the older part of the Atlantic until the Older Subboreal. Most of the flint artefacts discovered along with a collection of vessel fragments in the Mierzyn-Dołuje area are associated with the Neolithic occupation. However, changes in the deposits' geochemistry do not reflect all the settlement stages associated with the consecutive human groups identified by archaeological evidence. Possible reasons include a low sediment accumulation rate having restricted peat mass accretion and prevented the storing of any higher amounts of water. This, along with the climate-changecaused lowering of the water table, could have periodically stopped the accumulation of autochthonous organic matter. In addition, intensified human activities coincided with periods of stable and low water level in the basin. On the other hand, breaks in human activity correspond with moist Holocene stages and local flooding events. [ABSTRACT FROM AUTHOR]

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