Legacy product - no abstract available

Legacy product - no abstract available

A new project aimed at unravelling the geochemical composition of Australia's regolith has recently been approved under the Australian Government's new Onshore Energy Security Initiative (OESI). The primary aim of the National Geochemical Survey of Australia (NGSA) will be to provide actual concentrations and distributions of elements useful in targeting energy resources (uranium, thorium, other elements indicative of hot granites, etc.). The project will complement other OESI projects focussing on airborne radiometrics, airborne electro-magnetics and geothermal resources. The NGSA project will adopt a cost-effective, ultra-low density, landscape-based sampling approach to select sampling sites. Collection, preparation and analysis of surface and near-surface transported regolith samples will closely follow protocols established during pilot projects recently carried out by Geoscience Australia and the Cooperative Research Centre for Landscape Environments and Mineral Exploration, which revealed strong bedrock signatures in those materials.

Groundwater can interact with mineralisation at depth and, under appropriate circumstances, retain and transport a chemical signature in the form of major, trace element and isotopic fingerprints. These can be used to vector back to their source and hence help locate ore bodies under regolith or rock cover. As part of mineral exploration campaigns carried out by Anglo American in Chile and India, groundwater samples were collected from bores and wells to evaluate the usefulness of hydrogeochemistry in mineral exploration. Comprehensive and high quality chemical and isotopic analyses were carried out and thermodynamic and reaction path modelling was undertaken. Major element concentrations, ratios and isotopes reflect evaporation, water-regolith-rock interaction and mixing processes. Gradients in (1) concentration of ore and related elements, and (2) saturation index of ore and alteration minerals may reflect proximity to mineralisation and be useful to vector toward mineralisation.

I5 : Batten Trough Deep Seismic Reflection Traverses

No abstract available

No abstract available

Australian mineral exploration spending in 2004-05 rose by 31% to $1028.3 million of which 39.3% was spent on the search for new deposits. Total global non-ferrous mineral exploration budgets rose 38% to an estimated US$5.1 billion in 2005. Western Australia received 59% of Australian mineral exploration spending in 2004-05 as spending rose in all States except Victoria. Gold remained the main target but its share of spending was eroded by increased spending on nickel, copper, iron ore, coal and uranium. Exploration resulted in significant increases in resources at known deposits and a substantial number of drill intersections of economic interest, the most notable being the discoveries of copper-gold mineralisation at Carrapateena (Gawler Craton), mineral sand in the Eucla Basin, and gold at the Trident deposit (Yilgarn Craton).

This disc contains scanned PDF copies of uranium-related reports held by Geoscience Australia from the archives of the former Australian Atomic Energy Commission. These reports date from the 1950s to the 1980s. The reports are a mix of exploration reports, geological and geographical maps, proposals, feasibility studies, estimations, reserve information, drill hole data and drill cross section files.

The available geological data suggest two stages of hydrothermal activity at a number of sub-economic iron-oxide copper-gold systems of the Olympic Dam region of the Olympic Cu-Au province of the eastern margin of the Gawler Craton. They contain high- (>400?C), and moderate- to low-(200 to 300C?) temperature Fe-oxide rich hydrothermal alteration. The mineral assemblages are CAM: calcsilicate - alkali feldspar ? magnetite ? Fe-Cu sulphides, and HSCC: hematite-sericite-chlorite-carbonate ? Fe-Cu sulphides ? U, REE minerals ([Skirrow, 2002 #563; Skirrow et al., this volume). The bulk of the sub-economic Cu-Au mineralisation is associated with HSCC stage. Microanalytical results by PIXE, however, demonstrate that significant amount of copper (>500 ppm) has been transported by early-stage high-temperature fluids. These fluids were recorded as extremely concentrated fluid inclusions with multiple solid phases, compared to relatively simple liquid-vapour inclusions of the HSCC stage. Sulfur isotopes demonstrate that sulphur in these system was be derived either from magmatic rocks by relatively oxidised fluids (?34Ssulfides from ?5 to 2?), or from crustal sedimentary rocks (?34Ssulfides from 5 to 10?). Oxygen and hydrogen isotopes suggest ?metamorphic? rather then ortho-magmatic origin of the HSCC fluids. These observations can be reconciled with a two-stage model where pre-existing geochemical trap of hydrothermal magnetite (? sub-economic copper-gold mineralisation) is flushed by oxidised brine of sedimentary or metamorphic origin. The reduction of this brine due to magnetite to hematite conversion results in precipitation of copper and gold.