Provenance of mineral dust deposited on Antarctica over the last sixty years by strontium isotopic analysis of snow from Dome C

Abstract

The strontium (Sr) concentration and ⁸⁷Sr/⁸⁶Sr isotope ratio have been determined in 132 snow pit samples collected at Dome C, on the East Antarctic Plateau, corresponding to the period 1958–2019, and in 12 surface snow samples collected at the same site in 2016–2017. The average Sr concentration was 8.1 ± 5.7 pg g⁻¹ (mean ± SD) in snow pit samples and 10.1 ± 8.0 pg g⁻¹ (mean ± SD) in surface snow, without any significant temporal trend. The ⁸⁷Sr/⁸⁶Sr isotope ratio showed small variations (<0.15%), with an average ⁸⁷Sr/⁸⁶Sr value of 0.7094 ± 0.0010 (mean ± SD) in snow pit and 0.7103 ± 0.0004 (mean ± SD) in surface snow samples. These results seem to suggest that no change in the source(s) of mineral dust has occurred throughout the period investigated.

Comparison of the ⁸⁷Sr/⁸⁶Sr isotope ratio of the snow samples with those of potential source areas suggests that the mineral dust reaching the East Antarctic plateau over the last decades is of a mixed origin, with a contribution from Patagonia and one or more other source(s) having a more radiogenic Sr isotopic signature, with a major fraction coming from South Australia.