A comparable rate of 0. These rates were confirmed by annual layer varve -counts which lead to rates of 0. Constant Pb activities were observed in the top 6 cm of the sediment cores. This constancy is generally explained in the literature by mixing processes caused by bioturbation and by distortion during coring operations of the uppermost water-rich fluffy sediments. However the distinct Cs-maxima and the regular and undisturbed varve lamination of the top sediment observed in the cores of Lake Zurich contradict this assumption. Remobilization processes are assumed to cause the observed constant Pb activities. The results of the Pb dating should therefore be considered with some care. If existent, varve counting represents the easiest and most reliable means for dating lake sediments. Sedimente aus dem Zürichsee wurden mit Hilfe von drei unabhängigen Methoden datiert. Für Pb ergaben sich Sedimentationsraten von 0. Die Cs-Datierung und die Auszählung von Jahreslagen Varven ergab 0. Ähnlich wie in anderen Seen wurden auch im Zürichsee in den obersten 6 cm aller untersuchten Kerne konstante Pb-Aktivitäten festgestellt. Dies wird in der Literatur in der Regel auf Bioturbation oder auf sekundäre Durchmischung der stark wassergesättigten Sedimente bei der Probennahme zurückgeführt. Auch das Vorhandensein des kurzlebigen Isotopes 7 Be HWZ 53 Tage in den obersten Sedimentschichten beweist eine komplette und ungestörte Probennahme. Für die beobachtete konstante Pb-Aktivität werden daher Remobilisationsprozesse nach der Ablagerung der Sedimente verantwortlich gemacht. Nachträgliche Remobilisierung könnte auch die Ursache für das beobachtete unvollständige- Pb-Inventar in den Sedimenten sien, das nur ca. Die Untersuchungen zeigen, dass die Ergebnisse der Pb-Datierung in diesem eutrophen See mit Vorsicht interprtiert werden müssen und dass die Auszählung von Jahreslagen—falls vorhanden-die am wenigsten aufwendige und genaueste Methode zur Datierung von Seesedimenten darstellt. This is a preview of subscription content, log in via an institution to check access. Rent this article via DeepDyve. Institutional subscriptions. Goldberg E. Krishnaswami S. LermanSpringer Article Google Scholar. Sturm M. Google Scholar. Eakins J. Figgins P. Atomic Energy 210pb dating, NAS-NS, p. Robbins J. Acta 39 Article CAS Google Scholar. Smith J. Acta 44 Züllig H. Turekian K. KUeR Report, 25 Jahre Radioaktivitätsüberwachung in 210pb dating Schweiz, Eidg. Kommission 210pb dating Überwachung der Radioaktivität, Fribourg, Switzerland Kelts K. Download references. Present address: Eidg. Institut für 210pb dating, CH, Würenlingen, Switzerland. Institut für Reaktorforschung and Anorg. Present address: Dept.
Copy to clipboard. Stieg, Amelie ; Biskaborn, Boris K ; Herzschuh, Ulrike ; Strauss, Jens ; Pestryakova, Luidmila A ; Meyer, Hanno : Hydroclimatic anomalies detected by a sub-decadal diatom oxygen isotope record of the last years from Lake Khamra, Siberia. Ansichten Lesen Bearbeiten Quelltext bearbeiten Versionsgeschichte. Remobilization processes are assumed to cause the observed constant Pb activities. Browse in GEO-LEOe-docs.
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Reconstruction of the pollution history of Mumbai mudflat sediments using magnetic, chemical and Pb dating methods ; Nathani Basavaiah at Indian Institute of. We present a dating method for deep-sea sediments that uses the natural radionuclide Th (half-life 75, years) in analogy to Pb with the constant rate. Für diese Seite sind keine Informationen verfügbar.Received : 30 July Sorry, a shareable link is not currently available for this article. You can download the citation in several formats below. The results of the Pb dating should therefore be considered with some care. If existent, varve counting represents the easiest and most reliable means for dating lake sediments. We also investigate errors due to a violation of model assumptions by variable focusing of deep-sea sediments by means of a simulated core. Züllig H. Smith J. Institut für Reaktorforschung, CH, Würenlingen, Switzerland. Sturm M. Issue Date : March Tracking Hg historical inputs by Pb geochronology for the Itapessoca Estuarine Complex, Pernambuco, Brazil Article 20 July Erten Present address: Dept. Article CAS Google Scholar. This is a preview of subscription content, log in via an institution to check access. Als PDF herunterladen Druckversion. About this article Cite this article Erten, H. Supplement to:. Alle Publikationen. Finally, we use real examples from independently dated sediment cores containing carbonate, using previously existing Th data, to test the approach. Age, dated. However the distinct Cs-maxima and the regular and undisturbed varve lamination of the top sediment observed in the cores of Lake Zurich contradict this assumption. Abstract Pb- and Cs-measurements, and varve counting have been used to date sediment cores from Lake Zurich Switzerland. Author information Author notes E. Freeze-dried subsamples of the short core EN were analysed for Pb, Ra, Cs and Am by direct gamma assay in the Liverpool University Environmental Radioactivity Laboratory, using Ortec HPGe GWL series well-type coaxial low background intrinsic germanium detectors Appleby et al.
