Proxies and Measurement Techniques for Mineral Dust in Antarctic Ice Cores

Abstract

To improve quantitative interpretation of ice core aeolian dust records, a systematic methodological comparison was made. This involved methods for water-insoluble particle counting (Coulter counter and laser-sensing particle detector), soluble ion analysis (ion chromatography and continuous flow analysis), elemental analysis (inductively coupled plasma mass spectroscopy at pH 1 and after full acid digestion), and waterinsoluble elemental analysis (proton induced X-ray emission). Antarctic ice core samples covering the last deglaciation from the EPICA Dome C (EDC) and the EPICA Dronning Maud Land (EDML) cores were used. All methods correlate very well among each other, but the ratios of glacial age to Holocene concentrations, which are typically a factor ∼100, differ between the methods by up to a factor of 2 with insoluble particles showing the largest variability. The recovery of ICP-MS measurements depends on the digestion method and is different for different elements and during different climatic periods. EDC and EDML samples have similar dust composition, which suggests a common dust source or a common mixture of sources for the two sites. The analyzed samples further reveal a change of dust composition during the last deglaciation.

Water-soluble organic carbon in snow and ice deposited at Alpine, Greenland, and Antarctic sites: a critical review of available data and their atmospheric relevance

“…Furthermore, an alternative explanation may be that the sampling made with a polypropylene scoop and storage in sealed low-density polyethylene bags has caused contamination of samples. It has here to be emphasized that the dust content observed in these samples (Coulter counter measurements) appears also rather high, reaching for instance 400 to 2000 ppb in the DML transect compared to the mean value of 30 ppb observed in the Holocene ice at DML (Ruth et al, 2008).…”

Glacial–interglacial dynamics of Antarctic firn columns: comparison between simulations and ice core air-δ<sup>15</sup>N measurements

“…During glacial periods, the coastal or semi-coastal sites are expected to undergo surface temperature and accumulation rates that fall within the densification model empirical validity range. Each of these sites is also characterized by a specific magnitude of glacial-interglacial changes in local insoluble dust concentration (Ruth et al, 2008;Albani et al, 2012;Lambert et al, 2012), allowing us to test Hypothesis C. Using these new datasets, together with water isotope profiles and tests conducted with firn models, we investigate and discuss the different hypotheses presented above and their ability to explain the past firn structure dynamics for semi-coastal and coastal Antarctic sites.…”

A combined observational and modeling approach to study modern dust transport from the Patagonia desert to East Antarctica

“…NssCa 2+ concentrations in ice cores are commonly used to infer information about terrestrial inputs in polar regions (Wolff et al, 2006), even if the quantitative relationship between nssCa 2+ and dust are not fully defined for different climatic regimes, depending on dust mineralogy (e.g. Bigler et al, 2006;Ruth et al, 2008); however nssCa 2+ is calculated from Na + and Ca 2+ concentrations (using the formula nssCa 2+ = Ca 2+ -(Ca 2+ /Na + )sw * Na + , where sw stays for sea water), measured with high sensitivity in ice and aerosol samples by Ion Chromatography . Data presented in this work come from nssCa 2+ measurements performed on aerosol samples collected by 8-stage Andersen impactor for size-resolved (from 0.4 to 10 µm) aerosol collection.…”