From global 137Cs to determinations of the sedimentation rate in deep lakes and sea estuaries

Abstract

Sedimentation rate in deep lakes and estiaries of the Baltic, Pechora, and Laptev Seas was determined using global 137Cs as a sedimentogenesis marker. The sedimentation rate in Lake Ladoga and Levinson- Lessing Lake was 0.3–3 mm year−1, and that in estuaries of the Baltic, Pechora, and Laptev Seas was 0.74–1.76, 1.0, and 3.3–5.0 mm year−1, respectively. At a sedimentation rate of >1–2 mm year–1, the concentration peaks of global and “Chernobyl” 137Cs in the bulk of the bottom sediments do not overlap, and the sedimentation rate is estimated for each kind of nuclides separately. At a sedimentation rate of <1 mm year−1, “Chernobyl” 137Cs + 137Cs from dumping into sea mask in the bottom sediments the subsurface maximum of the global 137Cs concentration and prevent the sedimentation rate determination. The use of 137Cs for sedimentation rate determinations is appropriate for the poorly studied shelf zone of Russian Arctic seas.