Authors / CoAuthors
de Caritat, P. | Grunsky, E.
Abstract
The National Geochemical Survey of Australia (NGSA) project (www.ga.gov.au/ngsa) was part of Geoscience Australia's Onshore Energy Security Program 2006-2011 and was carried out in collaboration with the geological surveys of all States and the Northern Territory. It delivered (1) Australia's first national geochemical atlas, (2) an underpinning geochemical database, and (3) a series of reports. Catchment outlet sediments (similar to floodplain sediments in most cases) were sampled in 1186 catchments covering ~80% of the country (average sample density 1 sample per 5500 km2). Samples were collected at 2 depths each sieved to 2 grain size fractions. Chemical analyses carried out on the samples fall into 3 main categories: (1) total (using mainly XRF and total digestion ICP-MS), (2) aqua regia, and (3) Mobile Metal Ion® element contents. Here results of robust multi-variate analysis performed on the total element content data are reported. After clr-transformation of the raw data, a principal components (PCs) analysis was undertaken. The first five PCs account for 59.2% of the total variance. For instance, PC1 (27.9%) is dominated by Mg, Ca, S and Sr (negative loadings) and rare earth elements and Y (positive loadings). Thus, the PC1 map should reflect the distribution of carbonates and gypsum as well as resistate minerals typical of highly weathered environments and heavy mineral sands. By comparing this to known occurrences of rock and soil types, weathering regimes, etc. inferences can be drawn about the major, continental-scale processes influencing the distribution of chemical elements in Australia's surficial environment.
Product Type
nonGeographicDataset
eCat Id
73405
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Custodian
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
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- External PublicationAbstract
- ( Theme )
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- regolith
- ( Theme )
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- geochemistry
- ( Theme )
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- mineral exploration
- ( Theme )
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- environmental
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2012-02-08T00:00:00
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geoscientificInformation
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[-44.0, -10.0, 112.0, 154.0]
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