CHANGES IN ZINC AND CADMIUM CONCENTRATIONS IN GREENLAND ICE DURING THE PAST 7760 YEARS

Analysis of Zn and Cd in Greenland Holocene ice dated from 7760 to 471 yr ago shows no significant changes during the Greek, Roman and medie val times. It indicates that emissions from early mining and smelting operations were not intense enough for these two metals to have left d etectable signals in Greenland ice above natural background, contrary to what was previously observed for Pb and Cu. Zn was especially used during Antiquity to make brass, the important binary Cu-Zn alloy which was probably produced as early as similar to 4000 yr ago. Rock and so il dust and continental biogenic sources are found to be important con tributors to natural Zn and Cd in Holocene Greenland ice. During perio ds without major volcanic events, contribution from volcanoes was prob ably insignificant for Zn but could be important for Cd. (C) 1997 Else vier Science Ltd.