Soluble and insoluble lithium dust in the EPICA DomeC ice core—Implications for changes of the East Antarctic dust provenance during the recent glacial–interglacial transition

Abstract

Continental dust impurities in Antarctic ice provide information on climate changes in the dust source areas and on past atmospheric circulation. We investigated records of dust species from the last 45 ka in the East Antarctic EPICA DomeC (EDC) ice core with special emphasis on the lithium (Li) content of dust. We obtained two complementary Li-records using a new Ion Chromatography (IC) technique in line with Inductively Coupled Plasma-Sector Field Mass Spectroscopy (ICP-SFMS). Concentrations of soluble Li (Li + ) were obtained using IC, while total concentrations of Li (Li T ) were obtained using ICP-SFMS, providing an ideal opportunity to investigate the soluble and insoluble chemistry of Li in East Antarctic dust over the last glacialinterglacial transition. The records show that changes in the solubility of Li are associated with climatic changes. For the late glacial period and the Antarctic Cold Reversal (ACR) a large fraction, up to 75%, of the Li T content is present as insoluble minerals whereas for the Holocene period it seems that Li is present mainly as soluble salts (Li + ). We compared the concentrations of Li + with the concentrations of Ca 2+ and the mass and size characteristics of the dust, which were obtained using Coulter Counting (CC). Furthermore we compared the concentrations of Li T with the concentrations of Ba T . Our analysis suggests that the changes in solubility of Li along the EDC ice core are related to changes in compositions of the dust minerals. During the late glacial period, changes in the dust composition is characteristic of variations in the strength of the atmospheric circulation, while changes over the last glacial-interglacial transition are indicative of a change in the major dust source areas. The dust characteristics for the glacial and the Holocene periods indicate two different dust types. The glacial dust type partly disappeared after the ACR, while the Holocene dust type appeared significantly after around 16 ka BP and became dominant after the ACR. The relative increase in the Holocene dust type at the glacial-interglacial transition could be due to changed conditions in the potential source area or to changed patterns of atmospheric circulation, resulting in enhanced transport from a source area that was different from the glacial source areas.

Ultra-low rare earth element content in accreted ice from sub-glacial Lake Vostok, Antarctica

“…Ce an shows marked glacial/interglacial variation that may indicate contributions of aeolian dust from different sources during different climatic periods, as suggested by previous work (Delmonte et al, 2004a;Siggaard-Andersen et al, 2007;Ruth et al, 2008). A large variation in Ce an Distance above Lake Vostok (m) appears in AC 1 where we can observe the maximum Ce an (1.33) and the most negative Ce an (0.76), similar to typical Ce an found in saline marine waters (Alibo and Nozaki, 1999).…”

Comparing modeled and observed changes in mineral dust transport and deposition to Antarctica between the Last Glacial Maximum and current climates

“…Grousset and Biscaye 2005). More recently, new isotopic and elemental composition systems (e.g., Pb, Li, He isotopes) have been utilized to fingerprint geochemically the dust (Vallelonga et al 2010;Gabrielli et al 2010;Marino et al 2008;Winckler and Fischer 2006;Siggaard-Andersen et al 2007); yet, geochemical data There is increasing consensus that dust deposited in Antarctica during interglacial time periods is derived from a mixture of dust sources rather than a single source. Potential sources include different regions within southern South America and other sources like AUS (Revel-Rolland et al 2006;Delmonte et al 2007) or possibly the PunaAltiplano area (Delmonte et al 2008a;Gaiero 2008), and match the limited data on the isotopic signature of interglacial dust from the studied ice cores.…”

Compositions of Dust and Sea Salts in the Dome C and Dome Fuji Ice Cores From Last Glacial Maximum to Early Holocene Based on Ice‐Sublimation and Single‐Particle Measurements

“…Previous studies on the mineralogy of EDC dust have identified that the dominant dust source area was Patagonia during the LGM and that multiple dust sources including Australia may have contributed after ~16 kyr BP (Delmonte, Basile‐Doelsch, et al, ; Delmonte et al, ; Gili et al, ; Marino et al, ; Revel‐Rolland et al, ; Siggaard‐Andersen et al, ; Vallelonga et al, ; Wegner et al, ). Atmospheric model simulations have suggested that Patagonian dust is transported via the lower troposphere, while Australian dust is transported via the middle to upper troposphere (Krinner et al, ; Li et al, ).…”