Respective influence of global pollution and volcanic eruptions on the past variations of the trace metals content of Antarctic snows since 1880's

Abstract

Forty‐eight successive dated snow samples collected in central east Antarctica covering a continuous time sequence between 1880's and 1977 have been analysed for Na, Mg, K, Ca, Fe, Al, Mn, Pb, Cd, Cu, Zn, and Ag in ultraclean conditions. For all the elements, both the concentrations and the enrichment factors observed in 1977 are very close to the ones observed 100 years ago, then confirming that the influence of global pollution is actually negligible for these elements in the remote areas of the southern hemisphere. During the last 100 years, the variations of the enrichment factors of Pb and Zn are shown to parallel rather well those of the global volcanic activity, which suggests that the high atmospheric enrichments observed presently for these two metals are likely linked with volcanism. Between 1912 and 1916 (±5 years), there is a very strong signal showing a definite peak for the concentrations of most of the elements: It could be linked with a major Antarctic volcanic eruption.