HR: 1340h
AN: V23A-1236    [Abstracts]
TI: Long-term and short-term erosion rates in river catchments of the Rhenish Massif and the Black Forest, Germany
AU: * Meyer, H
EM: hmeye_02@uni-muenster.de
AF: Geologisch-Paläontologisches Institut, Westfälische Wilhelms Universität, Corrensstr.24, Münster, 48149, Germany
AU: Hetzel, R
EM: rahetzel@uni-muenster.de
AF: Geologisch-Paläontologisches Institut, Westfälische Wilhelms Universität, Corrensstr.24, Münster, 48149, Germany
AU: Strauss, H
EM: hstrauss@uni-muenster.de
AF: Geologisch-Paläontologisches Institut, Westfälische Wilhelms Universität, Corrensstr.24, Münster, 48149, Germany
AB: We constrained long-term erosion rates from the concentration of cosmogenic ¹⁰Be in stream sediments in order to quantify the Late Quaternary denudation history of mountain ranges in central Europe. Four different catchments in Germany, ranging in size from 8 to 379 km² were investigated. Two of them, the Aabach and Möhne catchments drain predominantly low-grade Paleozoic metasediments. The other two, the Gutach and Acher catchments in the Black Forest are situated in Late Paleozoic granites. Erosion rates derived from the ¹⁰Be concentrations range from 29 to 86 mm/ka in the Rhenish Massif and from 26 to 91 mm/ka in the Black Forest. These spatially-averaged erosion rates integrate over the past 7 to 23 ka. Central to our investigation are questions concerning the relative importance of lithology and catchment relief on long-term erosion rates. Short-term erosion rates for all catchments were quantified by combining the amounts of suspended and dissolved loads in water samples with water discharge data and basin area. By analyzing the stable isotope signatures δ¹⁸O of river water and δ¹³C of dissolved anorganic carbon and by taking into account the precipitation and evaporation we corrected the dissolved load for organic, atmospheric and anthropogenic inputs. The preliminary short-term erosion rates vary between 9 and 33 mm/ka and are only about one third of the erosion rates derived from ¹⁰Be. The short-term erosion rates are complemented by erosion rates derived from the volume of sediment stored behind reservoirs of known age. These erosion rates range from 2 to 13 mm/ka and are lower than the erosion rates derived from river loads, as they do not take into account the dissolved load. Furthermore, we focused on dependence of lithology and land use on short-term erosion rates.
DE: 1800 HYDROLOGY
DE: 4918 Cosmogenic isotopes (1150)
DE: 5415 Erosion and weathering
DE: 9335 Europe
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting