RECENT SEDIMENTATION OF THS CORE IN SOUTHERN TAIHU LAKE INFERRED FROM ~(137)Cs AND ~(210)Pb MEASUREMENTS

THS core was collected from southern Taihu Lake.Three distinct peaks of ~(137)Cs are observed in the core.Results of ~(137)Cs analyses indicate disturbance in the top surface.Up-core transference of ~(137)Cs peak of Chernobyl disaster is partially caused by high water content and organic matter in the sediment.Using depths recorded in 1963 and 1975 as the datum levels,the average sedimentation rate is calculated to be 0.34 cm/a.Corrected ~(210)Pb dates and sedimentation rates are calculated based on CRS model using the ~(137)Cs date in 1963 as a reference point.The results show that sedimentation flux rates are very high,reaching 0.6 g/cm·a around 1990s.The combination of these radionuclide dating methods is useful for us to understand the sedimentation process of the lake where sedimentation rates changed.