A highly radioactive Chernobyl deposit in a Scandinavian Glacier

A highly radioactive 0.5 cm thick ‘black line’ of dust with Chernobyl debris has been observed in two pits and an ice core, in snow and ice strata deposited at a temperate glacier in central Norway. The maximum deposition density of 137Cs found at this glacier was 59 kBq m−2. Over a deposition area of 100 cm2, concentrations of 137Cs at the same depth (horizontally) were about one order of magnitude while the vertical concentration over a 6 cm-thick layer of ice was about three orders of magnitude. The maximum concentration of 137Cs foundin ice containing the ‘black line’ was 1156 Bq kg−1, which is about 2–6 orders of magnitude higher than maximum concentrations recorded in other glaciers. High activities of this magnitude may provide us with a unique opportunity for environmental studies.