SEDIMENTARY RECORD OF PREHISTORIC AND HISTORIC HUMAN IMPACT, SUB-SUDETIC LOESS PLATEAU, POLAND

Located within the temperate climatic zone of Central Europe, the northern foreland of the Sudetes is covered by Quaternary deposits related to the Scandinavian glaciations which are in turn covered by loess several meters thick deposited during the last (Wurm/Vistulian) Pleistocene cool period. Rivers flowing northward from the Sudetes often cause large floods, the loess plateau receive up to 700 mm annual precipitation, and the local stream pattern is dense. The first farmers, migrating northward from the Danube Basin, crossed the line of Sudetes-Carpathians about 7000 years ago and settled on the loess Glubczyce Plateau. The farming and breeding tribes of the Early Bronze Age created the compact settlement structure of the Lusitian culture in this area about 1600-1300 years BC, leading to extensive deforestation of the populated areas. The first forest clearance began at this time. Following depopulation of the settled area in the Migration period, a new stage of agricultural colonization started in the region between the 8th and 10th centuries AD. Colluvial deposits found in the small dry valleys and alluvial fan deposits at the mouth of these valleys are sediments dating back to the periods in question. Fine grained overbank deposits infilling palaeomeanders in the vicinity of present-day channels indicate that the fossilization of organic material that filled these palaeochannels started in Early Medieval times, due to more frequent flood waves and an increased rate of overbank sedimentation. Analysis of heavy metal concentration indicates that these alluvia derived by transfer of sediments from the deforested loess Plateau.