Use of different analytical datasets to characterise dust and its provenance
Creators: name: Marando, Maria Elizabeth
Publisher: name: The Australian National University
Year: 2015

description: Aeolian dust is characterised by fine particles consisting of sand, silt, clays salt and organic matter which are suspended, transported and deposited by wind processes. Dust storms are highly influenced by soil properties, climate and anthropogenic activates. In Australia they can have many impacts on the environment, economy and human health. It is important to investigate their chemical (elemental, mineral and organic) composition and their source area to determine the composition of the dust, its origin and whether the source area can be better managed (i.e. undertake mine site rehabilitation or less cultivation on agricultural land). This project used a combination of ion beam analysis, mid infrared spectroscopy and carbon and nitrogen analysis to examine the chemical (elemental, mineral and organic)characteristics of six depositional dust samples with six matching soil samples from a case study site consisting of a 60m long transect located in the NSW Mallee. From the case study, an additional 38 depositional aeoilan dust samples from four sites in the rangelands of south west Queensland were analysed. Additionally this project, using Hysplit back trajectory analysis, determined the transport pathway and ultimately the source area of dust samples. The chemical analyses on the Jade case study site found a high enrichment of clay minerals and calcium carbonates in the dust samples and found the soil was more enriched in sandy minerals. A ratio of &gt;0.3 Al/Si also showed that the dust source is likely to be from an arid region situated west of the site. In addition, the carbon and nitrogen contents were very low for the Jade soil samples indicating that it is highly depleted of organic matter. Whereas the matching dust samples had a higher content of organic matter, thus indicating a source area remote to the paddock. In the Jade transect a “kinky” profile can be observed which indicates multiple sources areas, similar to those observed in previous studies. Hysplit back trajectory analysis confirmed the presence of multiple source areas for the dust samples, one source coming from the Mallee region and another from the Jade paddock soil. In the south west Queensland study, the chemical composition of the four rangeland sites indicated that the dust samples were quartz rich depositional material found on clay rich soils. The carbon and nitrogen content of the Charleville site were distinctive in that they showed an indication of an agricultural source region (i.e. Murray Darling Basin - MDB). The other sites (i.e. Longreach, Diamantina Lakes and Birdsville) showed lower carbon and nitrogen values indicating a source area closer to the depositional sites (the dust traps). In addition, the high quartz content of these four sites indicated a source in the Simpson Desert and possibly also the Lake Eyre Basin (LEB). The Hysplit back trajectory analysis confirmed that the main sources for dust in the four south west Queensland rangeland sites were the Simpson Desert, LEB and the MDB. This study found two different dust families, a parna which is native to south eastern Australia and is defined as a calcareous red earth dust and another family which is highly silica rich and sourced from central Australia, this dust sample is found in Queensland. The results will assist in building a relationship between aeolian dust deposits and their source areas. Additionally it will help to determine if the source site itself is in need of adaptive management, especially if it is an anthropogenic source such as a mine site or agricultural land.