A relationship between ion balance and the chemical compounds of salt inclusions found in the Greenland Ice Core Project and Dome Fuji ice cores

Abstract

We have proposed a method of deducing the chemical compounds found in deep polar ice cores by analyzing the balance between six major ions (Cl−, NO3−, SO42−, Na+, Mg2+, and Ca2+). The method is demonstrated for the Holocene and last glacial maximum regions of the Dome Fuji and GRIP ice cores. The dominant compounds depend only on the ion balance and the sequence of chemical reactions. In priority order, the principle salts are calcium sulfate, other sulfates, nitrate, chloride, and carbonate. The chemical abundances deduced by this method agree well with the results of Raman spectroscopy on individual salt inclusions. The abundances in the ice cores are shown to reflect differences in climatic periods (the acidic environment of the Holocene versus the reductive environment of the last glacial maximum) and regional conditions (the marine environment of Antarctica versus the continental environment of Greenland).