Alexandra Raab

Opencast mines in South Brandenburg (Germany)—archives of Late Quaternary landscape development and human-induced land use changes

This study outlines the opportunities for geoarchaeological research in active opencast lignite mines in southern Brandenburg (Germany). Studies on extensive outcrops that address both archaeology and soil geomorphology, combined with a geographical information system (GIS) approach, provide unique insights into human-induced environmental changes in Lower Lusatia and generally improve our understanding of landscape dynamics. We present the most recent results from three case studies and review important findings from the last several years. Studies conducted in opencast mines of Cottbus-Nord and Jänschwalde focus on (i) Late Quaternary geomorphodynamics and soil development and (ii) past land use and the legacy of agriculture and woodland use. Our results are similar to those in other regions in Central Europe, but we also observe regional differences caused by the local setting, e.g. intensification of soil erosion coinciding with the expansion of farming of cultivated lands in the Slavic Middle Ages. Our research reveals the largest archaeologically investigated area of historical charcoal production in the Northern European Lowland (NEL). We are clearly only beginning to understand the massive dimensions of charcoal production in the region.

Formation, classification and properties of soils at two relict charcoal hearth sites in Brandenburg, Germany

Historical charcoal production can have significant effects on soil properties. We studied soils at former charcoal production sites (relict charcoal hearths, RCHs) and compared these soils with undisturbed soil next to the charcoal hearths and four typical soils on similar parent material located at distances between 10 and 70 km from the RCHs. In a landscape typical of the northern German lowland, we found Podsolige Braunerde (WRB: Brunic Arenosols (Protospodic)) outside of the RCHs and soils with a clearly different stratigraphy within the RCHs. The main feature of the soils at both of the studied RCHs is a heterogeneous, charcoal-bearing deposit that is approximately 30 cm thick. No indications of translocation or mineral transformation processes, which form distinct soil horizons after the deposition of anthropogenic material on the RCHs, are present. Except for the differences in color and total carbon content, the soil chemistry of the RCHs hardly differs from that of the soil outside of the charcoal hearth sites. The soil colors and magnetic susceptibility values strongly suggest that the RCH substrates and the underlying topsoil were affected by thermally induced transformation of iron (hydr-)oxides. Although the charring procedure normally requires approximately two weeks, the heating effect only reaches to a maximum depth of 8 cm into the buried soil below the charcoal hearths. The presence of reddish soil and an abrupt increase in magnetic susceptibility in the upper 2 cm of the soil below the charcoal hearths indicate the heat-induced transformation of iron (hydr-)oxides into maghemite. Brighter soil color and an increase in soil organic matter in the lower parts of the buried topsoil demonstrate the combustion of soil organic matter up to 5 cm depth below the RCH. According to the German Guidelines for Soil Mapping, the soils in the RCHs are classified as Regosols above Braunerde (WRB: Spolic Technosols (Arenic)). However, because the anthropogenic features of these soil sediments are disregarded in the German Guidelines for Soil Mapping, we suggest adapting the ‘M’ horizon to permit a jM horizon. Thus, the soils in the RCHs could be classified as Kolluviale Braunerde.

Reconstruction of the fire history in the Siedlungskammer Burgweinting (Bavaria, Germany) in relation to settlement and environmental history

Abstract Palaeoenvironmental investigations were carried out in the Siedlungskammer (prehistoric settlement area) Burgweinting (Regensburg, Bavaria, Germany) to reveal past settlement conditions and human impact on the environment. Two sequences were obtained from the Islinger Mühlbach Fen, in close proximity to the archaeological excavation site in Burgweinting, which documents an almost continuous settlement history since the Neolithic Period. The analyses of the sequences comprise stratigraphic, geochemical and microscopic charcoal analyses. For chronological information, radiocarbon dating was conducted on a total of 10 samples. Thus, the first long-term fire record was reconstructed for the investigation area, and the results were correlated, based on radiocarbon dating, with the available environmental information and settlement history in the Siedlungskammer Burgweinting. The fire record reveals an almost continuous, but alternating fire history. Furthermore, it shows that fire played an important role in the Siedlungskammer Burgweinting and that most probably as early as the Mesolithic hunterer–gatherers deliberately used fire.