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The article describes geological constraints on the formation of sandstone-hosted uranium depoists in paleovalleyes and paleochannels

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Predictive mineral discovery is concerned with the application of a whole of system process understanding to mineral exploration as opposed to an empirical deposit type approach. A mineral system process understanding can be derived from a consideration of five key questions, namely what is/are the: 1) geodynamic setting; 2) architecture; 3) sources and reservoirs; 4) drivers and pathways, and; 5) depositional mechanisms. The answers to these questions result in the identification of critical processes necessary for the function of a mineral system within a particular terrane, and permit the development of a targeting model. In this contribution we identify district scale critical orogenic gold mineral system processes for the late Archaean eastern Yilgarn Craton of Western Australia. During the geodynamic history of a terrane the critical processes which result in mineralisation change with time resulting in variations in mineralisation style. Proxies for critical processes have been mapped in an integrated GIS and are termed mappable mineral system process proxies (or MMSPP). In recognition of this, three separate time slices and a geochemical theme were analysed. Each MMSPP is given a weighting factor (WF) which reflects the spatial accuracy/coverage of the data and process criticality. For each theme/time-slice, a separate prospectivity map was created by summing the overlay or union of the spatial extent of each MMSPP, and adding the WF. A final target or prospectivity map was generated by a union of the four theme/time-slice prospectivity maps, and is tested against the known major deposits. The map 'discovered' the main gold camps and accounts for over 75% of the known gold in 5% of the area. This test verifies the process-based understanding and the appropriate mapping of the critical proxies. A further outcome from the map was the identification of a number of new target areas not known for significant gold mineralisation in what otherwise is thought to represent a mature terrane for gold exploration. The approach taken here has been to consider the Late Archaean gold deposits as a holistic system. Despite the recurring areas of uncertainty, this systems view has resulted in new findings that have generic applications to other mineral systems.

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ABSTRACT: Building on method developments achieved during a series of precursor pilot projects, the National Geochemical Survey of Australia (NGSA) project targets catchment outlet (overbank) sediments as a uniform sampling medium. These transported, fine-grained materials are collected (from a shallow and a deeper level) near the lowest point of 1390 catchments, which cover 91% of the country. Dry and moist Munsell® colour, soil pH and electrical conductivity and pH of 1:5 (soil:water) slurries are recorded and laser particle size analysis and infrared spectroscopy are performed. The dried samples are sieved into two grain-size fractions (<2 mm and <75 mm) that are analysed by x-ray fluorescence (XRF) and inductively-coupled mass spectrometry (ICP-MS) (multi-element, total analyses), by ICP-MS after aqua regia digestion (multi-element, including low level gold), and specialised methods for platinum group elements, fluorine and selenium. At the time of writing, 78% of the samples have been collected and most analyses are completed for the first 25% of samples. The project is due for completion in June 2011.

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The Frome airborne electromagnetic (AEM) survey is the largest of three regional AEM surveys flown under the 5-year Onshore Energy Security Program (OESP) by Geoscience Australia (GA). The aim of the survey is to reduce risk and stimulate exploration investment for uranium by providing reliable pre-competitive data. The Frome AEM survey was flown between 22 May and 2 November 2010, is approximately 95 450 km2 in area and collected 32 317 line km of new data at an average flying height of 100 m. The Frome AEM survey covers the Marree (pt), Callabonna (pt), Copley (pt), Frome (pt), Parachilna (pt), Curnamona, Olary and Chowilla (pt) 1:250 000 standard map sheets in South Australia and was flown largely at 2.5 km line spacing, with the northern portion flown at 5 km line spacing. GA partnered with, the Department of Primary Industries and Resources South Australia and an industry consortium. The survey results indicate a depth of investigation (DOI - depth of reliable signal penetration) of up to 400 m in areas of thin cover and resistive basement (e.g., Adelaidean rocks in the Olary Ranges). In Cenozoic - Mesozoic sediments in the Frome Embayment and the Murray Basin the DOI is up to 100-150 m. A range of under-cover features are revealed, including (but not limited to): extensions to known palaeovalley networks in the Frome Embayment; the under-cover extent of the Benagerie Ridge; regional faults in the Frome Embayment and Murray Basin; folded and faulted Neoproterozoic rocks in the Adelaide Fold Belt; Cenozoic - Mesozoic stratigraphy in the Frome Embayment; neotectonic offsets in the Lake Eyre Basin; conductive Neoproterozoic rocks associated with copper-gold mineralisation; and, coal-bearing structures in the Leigh Creek area, as well as groundwater features.

Legacy product - no abstract available

This disc contains PDF scans of uranium-related reports held by GA from the Australian Atomic Energy Commission archives. These reports date mostly from the 70s, with some which are much older (as early as 1901) but none newer than the early 80s. 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. These reports pertain to the South Alligator Valley, Katherine RIver and other uranium fields within Pine Creek region. It is one of four discs containing reports concerning uranium in the Northern Territory.