气候变化领域集成服务门户

High-resolution sediment chronologies with the best possible time control are essential for comparing palaeoecological studies with independent high-precision climatic, archaeological or historic data in order to disentangle causes and effects of past environmental, ecological and societal change. We present two varved lake sediment sequences from Moossee and Burgaschisee (Swiss Plateau) that have chronologies developed with Bayesian models and radiocarbon (C-14) dating of terrestrial plant macrofossils extracted from sediment samples with constant age ranges. We illustrate the potential of high-resolution C-14 dating for the construction of robust, high-precision sediment chronologies. The mean 2 sigma age uncertainties were reduced to +/- 19 cal yr for Moossee and to +/- 54 cal yr for Burgaschisee over the entire period of 3000 cal yr, while 2 sigma uncertainties of only +/- 13 cal yr and +/- 18 cal yr respectively, were achieved for shorter time intervals. These precisions are better than or comparable to those of previous varve studies. Our results imply that a sophisticated subsampling strategy and a careful selection of short-lived and well-defined terrestrial plant remains are crucial to avoid outlying C-14 ages. A direct linkage between palaeoeological studies with dendrochronologically dated, local archaeological sites as well as a precise comparison with high-resolution climate proxy data have become feasible.