Colluvial sediments originating from past land-use activities in the Erzgebirge Mountains, Central Europe: occurrence, properties, and historic environmental implications

Colluvial sediments originating from soil erosion on slopes have proven to constitute significant evidence for tracing past human impact on mountain landscapes. In the Central European Erzgebirge (Ore) Mountains, colluvial sediments are associated with specific landforms (footslopes, slope flattenings, dells) and cover a share of 11% (11,905 ha) of the regional soil landscape. Thirteen pedosedimentary sections with colluvial layers were investigated at five forested sites (520-730 m a.s.l.) within a context of mining archaeology, integrating data from pedology, archaeology, palaeobotany, and geochronology. The thickness of the gravel-bearing loamy, silty, and sandy colluvial layers is up to 70 cm, which are mostly located on top of the sections. The geochronological ages and archaeological data reveal a high to late medieval to post-medieval age of the colluvial sediments. Pollen data show a drastic decline of the mountain forests in the late twelfth to fifteenth centuries AD accompanied by an increase of pioneer trees and spruce at the expense of fir and beech. The primary cause of soil erosion and subsequent colluvial deposition at the sites investigated is medieval to post-medieval mining and other early industrial activities. A compilation of 395 radiocarbon and OSL ages, obtained from colluvial sediments at 197 upland sites in Central Europe, shows that anthropogenically initiated colluvial dynamics go as far back as the late Bronze Age to the early Iron Age. Most ages derive from the medieval to post-medieval period, corresponding to the general intensification of settlement and land-use activities including deforestation and widespread ore mining.