Stratigraphy and chronology of Late Quaternary floodplain sediments in a historic mining area, Vils River Valley, East Bavaria, Germany

摘要

Analysis of 288 percussion drillings from depths of up to seven meters and a 120 m long excavated section provide new and detailed information on the Late Quaternary to Late Holocene floodplain evolution from the most important Central European iron-mining region of the 15th century. The generalized sequence of the Vils River floodplain is built of five units representing facies of different genesis (rock/saprolite, gravel, sand, loam, peat) that are identified by physical, chemical, and mineralogical parameters (grain size, clast shape, and content, TOC, bulk mineralogy). Along the 87 km length of the valley, different units/facies are found at the Upper Vils River (UVR 1-5) and at the Lower Vils River (LVR 1-4b). In both river sections, fine-grained material (flood loam) forms the major part (up to 4 m) of the alluvial sequence. 29 age determinations (24 ~(14)C, 4 IRSL, 1 tree-ring analysis) show increasing accumulation of flood loam in the last millennium. The data correlate with the beginning of mining at the Vils River and hence suggest a causal connection with mining activities in the catchment-both on the slopes and in the floodplain-with intense deposition of flood loams.