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Comparing contemporary atmospheric dust loads in south eastern Australia with dust contributions to soils

Nicola Stromsoe 1, Sam Marx2, Hamish McGowan1
1University of Queensland, Brisbane, Queensland, Australia, 2University of Wollongong, Wollongong, New South Wales, Australia

Long-range Australian dust transport and deposition is acknowledged to play an important role in Earth's systems. For example, dust deposition is an important vector of nutrient input into soils and ecosystems. Despite this, dust emission rates in south eastern Australia have been little examined. Similarly, the contribution of dust for soil development downwind of major dust sources has also not been examined in detail. This study attempts to fill these knowledge gaps by quantifying dust transport and contribution to the soils of the Snowy Mountains in south eastern Australia, a region which is assumed to be an important sink for dust eroded from central Australia. Existing estimates of the contribution of dust to this region have largely relied upon coarse estimates from clay mineralogy or from isolated dust deposition events to the alpine snow pack. In this study, patterns in atmospheric dust concentrations and dust element composition were measured over the course of one year using a network of high volume samplers located in the Snowy Mountains. Atmospheric dust concentrations were converted to an estimate of dust surface flux. This provides a measure of contemporary dust input to the Snowy Mountains. Dust flux rates are then compared with estimates of dust input to the soils of the Snowy Mountains, calculated using a trace element mass-balance approach. Collectively these data provide an estimate of the geochemical significance of dust input in this region.