Seasonal variability in the input of lead, barium and indium to Law Dome, Antarctica

Lead (Pb) isotopic compositions and concentrations, and barium (Ba) and indium (In) concentrations have been determinedat monthly resolution in five Law Dome (coastal Eastern Antarctica) ice core sections dated from ~1757 AD to~1898 AD. 'Natural' background Pb concentrations in ~1757 AD av...

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Bibliographic Details
Published in:Geochimica et Cosmochimica Acta
Main Authors: Burn-Nunes, LJ, Vallelonga, P, Loss, RD, Burton, GR, Moy, AD\, Curran, M, Hong, S, Smith, AM, Edwards, R, Morgan, VI, Rosman, KJR
Format: Article in Journal/Newspaper
Language:English
Published: Pergamon-Elsevier Science Ltd 2011
Subjects:
Earth Sciences
Physical geography and environmental geoscience
Glaciology
Law Dome
Pirie
Southern Ocean
Antarc*
Antarctica
ice core
Online Access:https://doi.org/10.1016/j.gca.2010.09.037
http://ecite.utas.edu.au/76793
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Summary:Lead (Pb) isotopic compositions and concentrations, and barium (Ba) and indium (In) concentrations have been determinedat monthly resolution in five Law Dome (coastal Eastern Antarctica) ice core sections dated from ~1757 AD to~1898 AD. 'Natural' background Pb concentrations in ~1757 AD average ~0.2 pg g -1 and can be attributed to mineral dustand volcanic emissions, with 206Pb/207Pb ratios reaching up to 1.266 +- 0.002. From ~1887 AD to ~1898 AD, Pb concentrationsreached ~5 pg g -1 and 206Pb/207Pb ratios decreased to 1.058 +- 0.001 as a result of additional inputs of Pb from anthropogenicsources. Seasonal variability in the late 1880s has been investigated by decoupling volcanic Pb from the totalmeasured Pb concentrations, revealing spring and autumn maxima, and consistent winter minima, in anthropogenic Pband mineral dust (Ba) concentrations. We link this variability to the annual cycle in the position and strength of the AntarcticCircumpolar Trough and, the Southern Ocean westerly winds to the north of the trough region. During the autumn andspring seasons, these systems increase in strength, transporting more impurity laden air from the Southern Hemisphere continentalregions to Eastern Antarctica and Law Dome. As this Pb is isotopically identical to that emitted from south-easternAustralia (Broken Hill, Port Pirie) this implies a relatively direct air trajectory pathway from southern Australia to Law Dome(Eastern Antarctica).

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