Trace elements in accreted ice from the Vostok sub-glaciallake, Antarctica: Initial results

Abstract
We present in this study initial results on trace elements concentrations changes in the deepest part of the Vostok ice core. From 3310 m depth to the bottom of the ice core (3623 m), ice encountered is made of disturbed glacial ice by glacier dynamics and accreted ice from the sub-glacial lake Vostok. Since trace elements are involved in various biogeochemical processes, studying these elements in the accreted ice of the Vostok lake can lead to a better understanding of lake chemistry and life development in such extreme environment. Because concentrations to be measured in Antarctic ice are exceedingly low, such investigations on trace éléments require strict control of contamination problems and the use of ultraclean protocols. Initial results obtained for Zn concentrations changes show high variability ( <0.5 to 32 pg/g), with the lowest concentrations found in the accreted ice of the Vostok lake ( <00.5 pg/g). According to crustal enrichment factors close to unity, Zn seems to be mainly associated with crustal material.