Recent Deposition of 210Pb on the Greenland Ice Sheet: Variations in Space and Time

Abstract

Detailed ²¹⁰Pb profiles were determined for four “Chernobyl dated” snowpits sampled during a wide-ranging survey of the Greenland ice sheet during the 1988 season. The profiles from widely separated pits show little or no coherence; even for two pits only 40 km apart the profiles differ in detail. There does not appear to have been any seasonality in the deposition of ²¹⁰Pb onto the ice sheet in the two years since the Chernobyl accident. The total deposition of ²¹⁰Pb during this period (10-20 bq m^-2) was about 20 times less than has been observed at mid-latitude sites in the eastern United States. The three pits west of the ice-sheet divide recorded very similar depositional fluxes, while the one eastern pit had only two-thirds the average of the others, suggesting a west-to-east gradient in the deposition of ²¹⁰Pb, and perhaps other continentally-derived submicron aerosols, onto the Greenland ice sheet.