Changes in atmospheric heavy metals and metalloids in Dome C (East Antarctica) ice back to 672.0 kyr BP (Marine Isotopic Stages 16.2)
Résumé
Cu, Zn, As, Cd, Pb and Bi were determined by Inductively Coupled Plasma Sector Field Mass Spectrometry (ICP-SFMS) in seventy-seven sections of the 3270 m deep ice core drilled at Dome C at an altitude of 3233 m on the East Antarctic plateau as part of the European Program for Ice Coring in Antarctica (EPICA). The depth of the section ranged from 2368.85 m (263.6 kyr BP) to 3062.13 m (672.0 kyr BP). When combined with data previously obtained for the upper part of the core, it gives a detailed record of past natural variations in the concentrations of these heavy metals during the last eight climatic cycles from the Holocene back to Marine Isotopic Stage (MIS) 16.2. Concentrations of all metals are found to have strongly varied. For Cu, Pb, Bi and possibly Zn concentrations appear to be closely linked with climate conditions, with high values during glacial maxima and much lower values during interglacials. The situation is less clear for As and Cd, for which variations are less clearly linked with climate conditions. Rock and soil dust appears to be the main source of Cu, Zn, Bi and Pb during glacial maxima, and a significant source for these metals during interglacials, while As, Cd and Bi present a more complex inputs from several sources, with a particularly significant impact of volcanism.