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Determination of mass accumulation rates and sediment radionuclide inventories in the deep Black Sea

1994; Elsevier BV; Volume: 41; Issue: 11-12 Linguagem: Inglês

10.1016/0967-0637(94)90064-7

1879-0119

Ken O. Buesseler, Claudia R. Benitez‐Nelson,

Geology and Paleoclimatology Research

Accumulation rates were determined from a detailed profile of 210Pbexcess in the top 3 cm of a box core from the deep waters of the western Black Sea. The data suggest a mass accumulation rate (MAR) of 69 ± 3g m−2y−1, less than half the MAR determined by varve counting. It is concluded that recognizable laminae couplets are not formed annually in these sediments. Further support for this conclusion is provided by the well documented fallout peaks of 239,240Pu and 137Cs from atmospheric nuclear weapons testing in the 1960s and the 1986 Chernobyl reactor accident. The 210Pb derived MAR from the top 3 cm is significantly higher than the long-term MAR determined from 14C data, suggesting an increase in accumulation rates within the past 1000–2000 years. The sedimen inventories of 210Pbexcess and 239,240Pu match their expected supply, whereas most of the fallout137Cs remains in the water column. The measured increase in226Ra inventory in the top cm of this core matches the previously observed decrease in water column226Ra during the past 30 years.