Soluble salts in deserts as a source of sulfate aerosols in an Antarctic ice core during the last glacial period

Abstract

Chemical proxy data from ice cores provide information for understanding environmental changes. Despite large climate shifts, the flux of sulfate onto the ice in Antarctica has remained relatively stable over glacial-interglacial cycles. However, the mechanism behind the stable flux is controversial because of a lack of evidence for changes in multiple source emissions. Here, we present the sulfur isotopic record in the Antarctic Dome Fuji ice core, which provides a new constraint on the interpretation of sulfate aerosols. During the Last Glacial Maximum (LGM), the sulfur isotope ratio was depleted compared to that during the Holocene and was negatively correlated with terrestrial contributions. The isotope data suggest that the contributions from terrestrial gypsum were enhanced during the LGM. A potential source area for gypsum in the Antarctic ice core is the high-altitude region around the Atacama Desert, although other regions cannot be excluded. These results suggest that the salts in deserts should be considered a terrestrial source of Antarctic sulfate during the LGM.