Variations in atmospheric trace elements in Dome C (East Antarctica) ice over the last two climatic cycles

Concentrations of Li, Mg, Cr, Mn, Co, Cu, As, Rb, Cd, Ba and Bi have been determined by inductively coupled plasma sector field mass spectrometry (ICP-SFMS) in various sections of the new Dome C EPICA Antarctic ice core, down to the depth of 2193 m, covering a time period of two climatic cycles. The time resolution of these records is at least twice as good as previously published ultra trace elements profiles obtained from the Vostok ice core. During the ∼217 kyr period spanned by this record, a high variability in concentrations is observed for most elements, with low values during warm periods and high values during cold periods. The highest concentrations are recorded at the times of the last two glacial maxima (∼20 and ∼140 kyr BP). The timing and the amplitude of the main concentration peaks match remarkably well the insoluble dust concentration profile. It confirms that dust was the main carrier of atmospheric trace elements to East Antarctica during the cold periods. For Ba, Co, Cu and Rb the crustal contribution was also dominant during warm periods. For other elements the situation is more complex during interglacial periods, when other sources such as volcanic quiescent emissions, became possibly significant for several trace elements such as Cd and Bi. Peculiarly high concentration values are observed for Cd and Bi for a short depth interval dated at ∼18 kyr BP. It is the same depth interval in which elevated F− values were previously observed. These very high concentrations are attributed to fallout from major local volcanic emissions at that time.