Sulphate and chloride aerosols during Holocene and last glacial periods preserved in the Talos Dome Ice Core, a peripheral region of Antarctica

Yoshinori Iizuka,Barbara Delmonte,Ikumi Oyabu,Torbjörn Karlin,Valter Maggi,Samuel Albani,Manabu Fukui,Takeo Hondoh,Margareta Hansson

doi:10.3402/tellusb.v65i0.20197

Yoshinori Iizuka, Barbara Delmonte + Show 7 more

Open Access

https://doi.org/10.3402/tellusb.v65i0.20197

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Abstract

Antarctic ice cores preserve the record of past aerosols, an important proxy of past atmospheric chemistry. Here we present the aerosol compositions of sulphate and chloride particles in the Talos Dome (TD) ice core from the Holocene and Last Glacial Period. We find that the main salt types of both periods are NaCl, Na2SO4 and CaSO4, indicating that TD ice contains relatively abundant sea salt (NaCl) from marine primary particles. By evaluating the molar ratio of NaCl to Na2SO4, we show that about half of the sea salt does not undergo sulphatisation during late Holocene. Compared to in inland Antarctica, the lower sulphatisation rate at TD is probably due to relatively little contact between sea salt and sulphuric acid. This low contact rate can be related to a reduced time of reaction for marine-sourced aerosol before reaching TD and/or to a reduced post-depositional effect from the higher accumulation rate at TD. Many sulphate and chloride salts are adhered to silicate minerals. The ratio of sulphate-adhered mineral to particle mass and the corresponding ratio of chloride-adhered mineral both increase with increasing dust concentration. Also, the TD ice appears to contain Ca(NO3)2 or CaCO3 particles, thus differing from aerosol compositions in inland Antarctica, and indicating the proximity of peripheral regions to marine aerosols.

Highlights

Aerosols are of central importance for atmospheric chemistry and physics, the biosphere and climate (Poschl, 2005)
Antarctic ice cores preserve past aerosols, which are important proxies for past atmospheric chemistry (Legrand and Delmas, 1988; Legrand et al, 1988)
Most of the more detailed information on aerosol deposition in Antarctica on glacialÁinterglacial timescales stems from ice cores drilled on the Central East Antarctic Plateau (CEAP), including Vostok (Petit et al, 1999), EPICA Dome C (EDC) (Wolff et al, 2006; Lambert et al, 2008) and Dome Fuji (DF) (Fujii et al, 2003; Watanabe et al, 2003)

Summary

Introduction

Aerosols are of central importance for atmospheric chemistry and physics, the biosphere and climate (Poschl, 2005). Most of the more detailed information on aerosol deposition in Antarctica on glacialÁinterglacial timescales stems from ice cores drilled on the Central East Antarctic Plateau (CEAP), including Vostok (Petit et al, 1999), EPICA Dome C (EDC) (Wolff et al, 2006; Lambert et al, 2008) and Dome Fuji (DF) (Fujii et al, 2003; Watanabe et al, 2003) These interior sites have similar snow accumulation rates; for the insoluble dust, they have similar sources, similar depositional fluxes and similar changes in magnitude over glacialÁ interglacial cycles (Delmonte et al, 2004a, 2004b, 2008). In the present (late Holocene) climate, the most common aerosols in CEAP come from sea salt (sodium chloride) and marine biological activity (methansulphonic and sulphuric acids) in the Southern Ocean These compounds combine in the atmosphere to form sodium sulphate (Legrand and Delmas, 1988; Legrand et al, 1988).

Experimental method

Results and discussion

Soluble calcium composition in TD ice core

Conclusion