Determination of recent deposition rates in lake constance europe with radio isotopic methods
Dominik, J.; Mueller, G.; Mangini, A.
Sedimentology 28(5): 653-678
ISSN/ISBN: 0037-0746 Accession: 005126126
Sedimentation rates are determined with the 210Pb method in 8 sediment cores from Lake Constance. The rate of deposition in the main basin (Obersee) varies from .apprx. 0.06 g cm-2 y-1 in the central part to 0.13 g cm-2y-1 in the eastern part of the lake and then increases rapidly towards the Rhine delta. In the central lake area the rate of deposition was .apprx. constant since 1900, and dating with the 210Pb method is in good agreement with sedimentological observations. In the Konstanzer Trichter area the deposition rate has increased since .apprx. 1955 as a result of eutrophication and subsequent high carbonate production. Dating with 137Cs is fairly accurate for sediments deposited at a high rate, but is questionable for slowly accumulating ones. A positive correlation of 210Pb fluxes and sedimentation rates indicates that 210Pb flux into sediments follows the distribution pattern of solids. 210Pb profiles in 4 sediment cores interpreted in terms of a constant flux model display synchronous fluctuations of the sedimentation rate; their relation to long-range particulate input variations remains to be proved. Sedimentation rates determined with the 210Pb method were used to calculate recent nutrient and heavy metal fluxes. Anthropogenic fluxes of Zn and Pb are in the same range of magnitude as in other polluted areas in Europe and America.