Uni-Bayreuth grafik-uni-bayreuth



Archaeomagnetic dating of floodplain deposits from the Aufsess catchment (Upper Franconia, Bavaria, Germany)

Christian Zeeden1, Ulrich Hambach1, Markus Fuchs1, Elisabeth Schnepp2, Mathias Will1, Ludwig Zöller1
1 Chair of Geomorphology, University of Bayreuth, Germany
2 Chair of Geophysics, University of Leoben, Austria

P 4.8 in Climate change research

Alluvial sediments from the Aufsess floodplain (Upper Franconia, Bavaria, Germany) contain valuable information about the timing of the deposition of these geoarchives. The accumulation of floodplain deposits is suggested to reflect the human land use in the Aufsess catchment. We attempt to reconstruct sedimentation rates for the Aufsess floodplain presuming human activity being the controlling factor.
Three excavations in floodplain deposits were sampled for palaeomagnetic studies in 2007 and 2008. We conducted palaeomagnetic remanence measurements to obtain reliable palaeomagnetic data of the directions of the palaeomagnetic field. These directional palaeomagnetic data are compared to the German archaeomagnetic reference curve, and we apply archaeomagnetic dating to these sedimentary geoarchives.
Using this technique, we are able to reconstruct different sedimentation rates for historic time intervals from two sections near Voitmannsdorf. We obtained estimates for sedimentation rates of ca. 0.1 mm/yr for the time interval between 500 BC and Anno Domini. From Anno Domini till ca. 400 AD about 0.25 mm/yr were deposited in an average. Thereafter, until about 1,000 AD almost no sediment was deposited, but from ca. 1,000 AD onwards sedimentation increases.
These sedimentation rates are suggested to reflect the human impact onto the landscape (clearing, agriculture). We conclude from the present results that the land use intensity was low until Roman times, but increased between ca. Anno Domini and ~400 AD. Hereafter, we have no indication of erosion in the Aufsess catchment until ca. 1,000 AD. However, in medieval times (here from ca. 1,000 AD onwards) the human impact appears to increase sharply, this high intensity land use lasted until 1800 AD, at least.

last modified 2009-03-30