Geochemical And Pb Isotopic Signature Of peaty Sediments From Central-South Chile : Identification Of Particle Supplies Over The Holocene

François de Vleeschouwer (1) , Maud Ibanez (2) , Nadine Mattielli (2) , Claude Maerschalk (2) , Nathalie Fagel (1)

1 Université de Liège
2 ULB - Université libre de Bruxelles

Two cores from tephra rich peat soils of the Chilean Lake District were investigated for mineral source and potential anthropogenic impact using elemental geochemistry, including rare earth elements, and lead isotopes. The dominant particle source to the area are the Trumaos, which are the local ando soils derived from the weathering of volcanic deposits. In Galletué, although short term events of enhanced particle inputs occur, elemental and isotopic signatures show that the Trumaos are the only particle source to the área. In San Pablo de Tregua, punctual events of crustal particle inputs are recorded in Pb enrichment factors and isotopic profiles, reflecting a long range crustal involvement. This site also records the inception of the anthropogenic in the área in recent samples of which Pb enrichment factors and lead isotopic signatures shift drastically.

Mots clés: Peat soil; Trace elements; Pb isotopes; Ando soils; Lake District; Chile; Holocene

Domaines: Géologie appliquée; Ecologie, Environnement

François de Vleeschouwer, Maud Ibanez, Nadine Mattielli, Claude Maerschalk, Nathalie Fagel. Geochemical And Pb Isotopic Signature Of peaty Sediments From Central-South Chile : Identification Of Particle Supplies Over The Holocene. Journal of the Chilean Chemical Society, 2008, vol. 53, pp. 1640-1649. ⟨10.4067/S0717-97072008000300021⟩. ⟨hal-00985129⟩