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AMS-radiocarbon dates of bulk sediment samples were compared to AMS-radiocarbon dates of terrestrial plant macrofossils from two neighbouring lakes in northern Sweden. Both sediment successions cover the period from the last deglaciation to the present. The sediments in Lake Tibetanus are highly calcareous, whereas the laminated sediments in Lake Vuolep Njakajaure are composed mainly of algal gyttja with a low carbonate carbon content. The ages of the radiocarbon dated terrestrial macrofossils are in close Dating lake sediments with the lamina chronology in Lake Vuolep Njakajaure. All bulk sediment samples give older radiocarbon ages than radiocarbon ages obtained from terrestrial macrofossils. The magnitude of the radiocarbon age error in Lake Tibetanus is not constant throughout the profile but ranges from c.

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Deep sediment cores from long-lived lake basins are fundamental records of paleoenvironmental history, but the power of these reconstructions has been often limited by poor age control. Uranium-thorium U-Th dating has the potential to fill a gap in current geochronological tools available for such sediment archives.

High uranium concentrations 0. Despite this advantage, the dates from analyses on 55 bulk carbonate samples reveal ificant scatter that cannot be resolved with traditional isochrons, suggesting that at least some of the sediments have not remained closed systems.

We then compare these with facies types, trace element concentrations, carbonate and total organic carbon content, color reflectance, mineralogy, and ostracode shell color to investigate the causes of open system behavior. Alongside simulations of the isotopic evolution of our samples, we find that the greatest impediment to U-Th dating of these sediments is not detrital contamination, but rather post-depositional remobilization of uranium.

Examining U-Th data in these contexts, we identify samples that have likely experienced the least amount Dating lake sediments alteration, and use dates from those samples as constraints for the age-depth model. Our work has several lessons for future attempts to U-Th date lake sediments, namely that geologic context is equally as important as the accuracy and precision of analytical measurements.

In addition, we caution that ificant geologic scatter may remain undetected if not for labor intensive tests of reproducibility achieved through replication.

View PDF. Access through your institution Purchase PDF. Quaternary Science Reviews Volume15 September Author links open overlay panel Christine Y. Hatfield e f R. Lehmann c Joseph S. Abbott c Donald T. Rodbell n. Add to Mendeley Share.

Abstract Deep sediment cores from long-lived lake basins are fundamental records of paleoenvironmental history, but the power of these reconstructions has been often limited by poor age control. Keywords Quaternary.

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