Distribution of Ca, Fe, K, and S between soluble and insoluble material in the Greenland Ice Core Project ice core

We have developed an original method coupling particle induced X ray emission and scanning electron microscope/X ray dispersive analysis in order to characterize the partitioning of Fe, Ca, K, and S between the soluble and the insoluble phases in wind-blown deposits in the Greenland ice. We applied this technique to several sections of the Greenland Ice Core Project ice core. We found that the dominant fraction (from 25 to 100%) of Ca and S deposited in Greenland is soluble, while the proportion of soluble material is lower for K and Fe (between 10 and 80%). For all elements the distribution between soluble and insoluble material varies according to the ice-core depth. The distribution appears to be linked to either meteorological factors, such as temperature or pH of the precipitation (in the case of Ca or S), or the alterability of the mineral assemblages found in the ice (in the case of Fe and K). The fraction of soluble material is therefore linked to the characteristics of source origin (S is predominantly emitted in very soluble forms) and to the dissolution of certain minerals (such as calcium carbonate or Fe-oxides) during transport in the atmosphere. The dynamics of alteration processes is, however, still uncertain, especially for K-containing minerals.