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TitreDawn of the Anthropocene laced with arsenic: global atmospheric As contamination preserved in 3000 year old Arctic ice
AuteurKrachler, M; Zheng, J; Fisher, D; Shotyk, W
SourceGlobal Biogeochemical Cycles vol. 23, GB3011, 2009 p. 1-7,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20080598
ÉditeurAmerican Geophysical Union
Documentpublication en série
Mediapapier; en ligne; numérique
SNRC48E/14; 48E/15; 48H/02; 48H/03
Lat/Long OENS-82.5000 -81.5000 72.2500 71.7500
Sujetsglace; carottes; arsenic; bismuth; scandium; climat arctique; fluctuations climatiques; Holocène; Calotte glaciaire de Devon ; géologie des dépôts meubles/géomorphologie; géochimie; Quaternaire
ProgrammeRenforcer la résilience face aux changements climatiques
ProgrammeÉtudes paléo-environnementales sur les changements climatiques, Géosciences de changements climatiques
Résumé(disponible en anglais seulement)
Despite its growing environmental significance, there are no detailed historical records of atmospheric As deposition for the Northern Hemisphere. Having overcome the severe analytical challenges in measuring As in polar ice, and using an Arctic ice core representing ?16 ka of snow accumulation, we present a complete record of atmospheric As deposition for this period which reveals significant contamination beginning 3000 years ago. While Pb enrichments unequivocally increased threefold above natural background levels during Greek/Phoenician, Roman, and Medieval periods, As is elevated by a factor of 5. Previous studies showed that these periods are not only enriched in Pb but also Sb: here we show significant contamination not only by As but also Bi, Cu, and Zn. The Pb isotope data reveal declines in the ratio 206Pb/ 207Pb which reflects the introduction Pb-bearing aerosols from smelting of lead ores, but the metallurgy of copper ores must also have played a role. Taken together, these findings demonstrate a deeper, broader environmental significance of sulphide ore processing in antiquity, defining the origins of global atmospheric contamination for a suite of related elements and providing a new perspective on the start of the Anthropocene. In addition, the data indicate that by far the greatest As concentrations in the ice core are recorded during the Younger Dryas cold climate event centered around 12 ka B.P., demonstrating the strong link between global climate change and the atmospheric cycling of trace elements.