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UP: Fachverband Umweltphysik
UP 5: Postersession
UP 5.27: Poster
Dienstag, 14. März 2017, 16:40–18:10, GW2 B3010
Wollingster See: Dating of lake sediment core using natural and artificial radionuclides — •Manuel Perez-Mayo1, Hareem Ikram1, Daniela Pittauer2, Dirk Enters3, and Helmut W. Fischer1 — 1Institute of Environmental Physics, University of Bremen, Germany — 2MARUM, University of Bremen, Germany — 3Geopolar, University of Bremen, Germany
Lake sediment cores are valuable archives of the changing environment. They contain information on local and regional atmospheric deposition, including material from surroundings brought through erosion and specially metal pollutants. A very well know method to dating the last 100 years is based on the signal of 210Pbxs often supported by the peaks of 137Cs as absolute time markers (e.g. atmospheric bomb test fallout and Chernobyl).
Natural and artificial radioisotopes as 210Pb, 214Bi, 214Pb, 40K, 137Cs, 241Am and plutonium isotopes were analysed in a sediment core taken in a deep part of the lake Wollingster See (NW Germany) in order to provide a reliable chronology enabling to reconstruct the environmental changes.
Actual results show very high and apparently also quite variable sediment accumulation rates. 137Cs cannot be used as precise marker, as the bomb test and Chernobyl maxima can not be clearly indentified. In that case, we need to seek for information from additional radioisotopes like 241Am using techniques of spectra summing in gamma spectrometry and measuring Pu isotopes by alpha spectroscopy to distinguish better between nuclear weapons testing and Chernobyl deposition.