The Cs distribution in sediment profiles from the Yangtze River estuary: a comparison of modeling and experimental results.

It has been generally accepted when estimating sedimentation rates using the Cs dating method that the position of the Cs maximum in a sediment profile represents the year 1963. In this paper we validated this approach by developing a model in which the annual Cs global fallout flux for the Yangtze River estuary was established on the basis of the Tokyo flux corrected for precipitation rates observed in Shanghai. As the Cs maxima in the sediment deposition profiles depend on the sedimentation rates, the sub-sampling intervals were calculated accordingly. Higher measured than the calculated values were found in some cores, what may be due to fluctuating sedimentation rates and an additional deposition of Cs from land-based sources. The study provides useful information on the reliability of the measured Cs maxima in sediment profiles frequently used for dating of sediments in marine (coastal regions, open seas) as well as in terrestrial (lakes) environments. [ABSTRACT FROM AUTHOR]