Assessing the Quality of Thermally Drilled Deep Antarctic Ice Cores for Trace Elements Analysis

Concentrations of Pb, Zn, Na, Mg, K, Ca, Fe and Al have been measured in successive veneers of ice mechanically chiselled progressing from the outside to the very center of various sections of the Dome C and Vostok deep Antarctic ice cores. Mean elemental contamination present in the outside layer of the cores was foind to range from 0.3 ng/g (Al) up to 20 ng/g (Na) for the Dome C core, and from 5 ng/g (Al) up to 290 ng/g (Zn) for the Vostok core. Contrasting outside-inside curves were observed for the various elements. Plateaus of concentrations were obtained in the inner parts of the cores sections in all cases for Na and Mg, and in most cases for K, ca, fe and Al. For Pb and Zn, on the other hand, plateaus were observed only for part of the sections, which confirms that for these two heavy metals it is of utmost importance to study in details the variations of the concentrations from the outside to the inside of each core section if reliable data are to be obtained.