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

Abstract

Abstract. 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 p H 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.

Iron content and solubility in dust from high-alpine snow along a north-south transect of High Asia

“…As the end member of the Asian dust, dust in the Greenland Ice Core Project (GRIP) ice core shows iron solubility averaging about 40920% (Laj et al, 1997). Until now, both iron abundance and especially iron solubility of dust are not well understood, leading to a large uncertainty in assessing the exact iron flux and the impact of dust on the global biogeochemical cycle in models.…”

Determination of water-soluble, acid-extractable and inert fractions of Cd, Pb and Cu in Antarctic aerosol by square wave anodic stripping voltammetry after sequential extraction and microwave digestion

“…Traditionally, in Antarctic, and more generally in Polar, research devoted to the reconstruction of present and past changes in the chemical composition of the atmosphere through the analysis of aerosol or ice, only the total content of substances or the simple partition between soluble and insoluble fractions have been considered [1][2][3][4][5][6][7][8][9][10][11][12][13]. In particular as regards heavy metals, there is at present no information available in the literature, with the exception of our previous work [14,15], with reference to their distribution between the soluble and the insoluble fractions in aerosol, snow and ice.…”

20th-Century doubling in dust archived in an Antarctic Peninsula ice core parallels climate change and desertification in South America

“…Although atmospheric dustiness has been linked to large-amplitude, large-scale temperature changes in past ice core studies of glacial to interglacial transitions (10, 11), it is unclear whether projected climate warming in coming decades to centuries will result in more or less atmospheric dust (12). Decadal changes in dust flux have been reported for ice cores from the Antarctic Peninsula (13, 14), but reliable, high-time-resolution records of changes in dust levels during recent decades and centuries are sparse (15).Ice core records offer the possibility of reconstructing past changes in dust concentration (10,11,(13)(14)(15)(16)(17)(18)(19)(20). Most previous high-resolution ice core studies used as proxies of atmospheric dust the non-sea-salt component of soluble calcium (nssCa) or magnesium (nssMg) that are computed by using estimated elemental ratios in sea salt aerosols (11,19).…”

“…At many ice core sites, particularly coastal locations, the nssCa concentration may be uncertain because strong marine influences on glaciochemistry mean that up to 90% of total soluble calcium is derived from seawater, and varying fractionation of sea salt on sea ice surfaces and during transport means that the sea salt aerosol ratio does not always accurately reflect the seawater contribution (11,21). In addition, the nssCa-based proxy primarily represents the chemically weathered part of atmospheric dust because the bulk of nssCa and nssMg in atmospheric dust comes from finegrained calcium carbonate, dolomite, and gypsum deposits (17,18,(22)(23)(24)(25). The climate signal contained in the aluminosilicate dust record may differ significantly from that in the chemically weathered dust record because the former arises primarily from deposits of mechanically weathered sediments, such as glacial loess.…”

“…Ice core records offer the possibility of reconstructing past changes in dust concentration (10,11,(13)(14)(15)(16)(17)(18)(19)(20). Most previous high-resolution ice core studies used as proxies of atmospheric dust the non-sea-salt component of soluble calcium (nssCa) or magnesium (nssMg) that are computed by using estimated elemental ratios in sea salt aerosols (11,19).…”