Peat bogs as archives of local ore mining and smelting activities over the centuries: A case study of Miasteczko Śląskie (Upper Silesia, Poland)

One of the oldest areas of ore mining in Upper Silesia (southern Poland) is Miasteczko Śląskie, which is surrounded by numerous peat bogs developed in the Brynica Valley. These can offer a good alternative to standard archaeological investigations because they are valuable archives of climatic and anthropogenic impacts. The main aim of this study was to detect traces of human activity and historical mining and smelting in the Brynica River catchment using a combination of magnetic, radiometric and geochemical methods. The research was conducted on two peat profiles: Moczydła and Żyglinek. The application of mass-specific magnetic susceptibility (χ), the determination of the content of heavy metals (Pb, Cu, Zn, Cd, Fe) and radiocarbon dating allowed for investigation into the distribution of anthropogenic pollutants in the peat profile. Additionally, the enrichment factor (EF) of selected heavy metals was calculated. The results revealed the potential mobility of Cu, Zn and Cd in peat profiles and the lack of Pb mobility. Maximum enrichment of Pb could be observed in the Moczydła profile at a depth of 17 cm (5,996 mg kg⁻¹) and in the Żyglinek profile at a depth of 14 cm, where it amounted to 287 mg kg⁻¹ and dated back to the period 1300–1600 AD. However, in the Żyglinek profile a noticeable increase in the value of χ could be seen from a depth of 40 cm, where peat layers corresponded to 2700 BC. The high correlation observed between anthropogenic Pb (EF_Pb) and magnetic parameters (χ and χ/Fe) will be useful for the further study of the tracers of ore mining and smelting and other historical human impacts on the environment. It can support archaeological studies conducted at the sites of early settlements, which in Central and Northern Europe were very often located on hills surrounded by swamps and peat bogs.