Greenland NEEM ice core records of trace metals during the 1710~1970

Abstract

In this research, we present high resolution record of Al, As, Ba, Cd, Co, Cr, Mn, Mo, Pb, Rb, Sr and V from Greenland NEEM ice core samples covering the period from 1710 to 1970. To our knowledge, long-term trends of these elements except Cd and Pb have never been reconstructed from Greenland ice cores at such a high resolution. The ice core records of the trace metals concentrations are characterized by large fluctuations. The ratios between maximum and minimum concentrations range from 69 for Sr to 1596 for As indicating a stark variation in concentration with depth. To help understanding long-term changes in atmospheric trace metals, individual data points were averaged for a decadal period. The main features of long-term changes are all categorized into three groups. Al, Ba, Mn, Rb, Sr and V show no distinct peaks in their concentrations over the whole period. Meanwhile, Co, Cr and Mo concentrations are largely peaked from the mid-1830s to the mid-1850s and steadily increase for the 20th century. For As, Cd and Pb, two concentration peaks are appeared around 1800 AD and 1900 AD. The different patterns in the periods reaching peaks in concentrations are likely due to the primary anthropogenic sources for the different element. Our first comprehensive and reliable time series for various trace metals from Greenland NEEM ice core provide valuable insights into significant enrichments of these elements due to human activities from the early-19th to the mid-20th century.