Rare-earth-element (REE) mineral systems in Australia are associated with igneous, sedimentary, and metamorphic rocks in a range of geological environments (http://www.ga.gov.au/image_cache/GA19657.pdf). Elevated concentrations of these elements have been documented in various carbonatite intrusions, (per)alkaline igneous rocks, iron-oxide breccia complexes, calc-silicate rocks (skarns), fluorapatite veins, pegmatites, phosphorites, fluvial sandstones, unconformity-related uranium deposits, lignites and heavy-mineral sand deposits (beach, dune, marine tidal, and channel). The distribution and concentration of REE in these deposits is influenced by various rock-forming processes including enrichment in magmatic or hydrothermal fluids, separation into mineral species and precipitation, and subsequent redistribution and concentration through weathering and other surface processes. The lanthanide series of REE and yttrium, show a close association with alkaline felsic igneous rocks, however, scandium in laterite profiles has an affinity with ultramafic-mafic igneous rocks.

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Mapping of regolith materials at the regional and continental-scale for environmental, agricultural and resource exploration for is being advanced through a new generation of remote sensing technologies, particularly satellite remote sensing methods. The work has demonstrated the identification and classification of regolith materials and thickness indicators is essential to facilitate ongoing exploration in challenging regolith-dominated terrains, and that geochemical information about alteration chemistry associated with footprints of mineral systems can be acquired by analysing spectral ground response, particularly in short-wave infra-red.

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® (MMI) element contents. The MMI analyses were conducted on the surface (0-10 cm) samples sieved to <2 mm, in one single batch, by ICP-MS. Concentrations of 54 elements (Ag, Al, As, Au, Ba, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Hg, K, La, Li, Mg, Mn, Mo, Nb, Nd, Ni, P, Pb, Pd, Pr, Pt, Rb, Sb, Sc, Se, Sm, Sn, Sr, Ta, Tb, Te, Th, Ti, Tl, U, V, W, Y, Yb, Zn and Zr) were determined. Maps and quality assessment of these data are presented in reports available from the project website. Preliminary interpretations of the MMI dataset suggest that it potentially has significant value in geological, mineral exploration and agronomic (e.g., bioavailability) applications.

Diagenetic processes in sedimentary basins are capable of generating a spectrum of closely-related mineral systems such as unconformity-related uranium, Westmoreland-style uranium, sediment-hosted stratiform copper (Kupfersheifer), and stratiform zinc-lead-silver deposits. A close spatial association between uranium and copper deposits has been observed in many regions. Examples include: Rum Jungle uranium field where four deposits (Dyson U, Whites U-Cu-Co-Ni, Intermediate U-Cu and Browns Pb-Zn-Cu-Co-Ni) occur within ~ 2 kms of each other (McCready et al., 2004); Paterson Orogen which contains unconformity-related uranium mineralisation (such as Kintyre) and many copper deposits (such as Nifty) and lead-zinc prospects; Westmoreland uranium field hosting copper and uranium deposits; Athabasca Basin in Canada where both polymetallic and monometallic ores contain anomalous concentrations of base metals (Jefferson et al, 2007). At the other end of the spectrum the Kupfersheifer-style copper system, contain uranium-enriched zones. The richest known uranium deposit of this type is Shinkolobwe (~ 30000 t of U3O8) in the Katanga Province, Zambian Copper Belt.

Short movie showing ability of WorldWind to display geological and geophysical datasets

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The National Geochemical Survey of Australia (NGSA) project aims to provide pre-competitive data and knowledge to support exploration for energy resources in Australia (www.ga.gov.au/ngsa) and is part of Geoscience Australia's Onshore Energy Security Program. The NGSA project, which is carried out in collaboration with the geological surveys of all States and the Northern Territory, will deliver the nation's first geochemical atlas, a comprehensive geochemical database and preliminary reports when it concludes in June 2011.