Defining element associations and inferring geological processes from total element concentrations in Australian catchment outlet sediments: multivariate analysis of continental-scale geochemical data  

Authors / CoAuthors

de Caritat, P. | Grunsky, E.

Abstract

,,,/,,, Censored data (<Lower Limit of Detection) was imputed using a neural networks-based analysis. The compositional data was transformed using centred logratios (clr) to circumvent closure issues. A Principal Component Analysis (PCA) was then performed on the dataset. The four first PCs account for 59 % of the variance in the dataset. Both negative and positive loadings of each of these PCs relate to geological processes consistent with the element associations they represent as well as the spatial distribution patterns they produce. For instance, the positive loadings of PC1 represent the accumulation of resistant minerals rich in Rare Earth Elements (REEs) that results from intense weathering. Negative PC1 loadings represent secondary minerals formed during weathering (carbonates, sulfates, Fe-oxihydroxides). Negative PC2 loadings are a mixture of elements (e.g., Co, Mn, Zn, V) characterising mafic and ultramafic minerals; conversely negative PC3 loadings (e.g., K, Rb, Na, Sr, Ca) represent more felsic minerals. Spatial distributions of the PCs are compared with independent spatial dataset such as geological maps, airborne radiometric and spaceborne spectroscopic datasets and the implied processes (e.g., lithological control, weathering, transport, secondary mineral precipitation) overall match well with this new geochemical evidence. Future work directions with this dataset include lithological prediction and mineral prospectivity analysis.

Product Type

nonGeographicDataset

eCat Id

74867

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Keywords

• External PublicationScientific Journal Paper

( Theme )

• regolith

( Theme )

• geochemistry

( Theme )

• mineral exploration

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_Internal

Publication Date

2012-11-01T00:00:00

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Australian Government Security ClassificationSystem    

Classification - unclassified

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Creative Commons Attribution 4.0 International Licence    

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Purpose

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unknown

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geoscientificInformation

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Unknown

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Extents

[-44.0, -10.0, 112.0, 154.0]

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Spatial Resolution

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