Paleolimnological assessment of recent environmental change in Lake Baikal: sediment chronology

Sediment cores collected from six sites in Lake Baikal as part of an extensive investigation of sediment records of recent environmental change were dated radiometrically by (210)Pb. Although the results obtained were in some respects comparable to those obtained by previous (210)Pb studies, there were some significant differences. Most notably, a core from abyssal depths in the centre of the middle basin appeared to record at least two major episodes of rapid sedimentation, possibly caused by turbidity currents. All cores, including those from the North Basin, contained significant records of weapons test fallout (137)Cs, though these were of little chronological value due to the long residence time of (137)Cs in the water column. Models and budgets for sediment and radionuclide transport through Baikal are presented and used to help validate the (210)Pb results.