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  • Uranium-rich igneous rocks are recognised as an important source of metals in uranium mineral systems. Magmatic-related uranium mineralisation may be orthomagmatic in origin, forming via favourable igneous processes, or may result from the exsolution of uranium-rich fluids from particular magmas. Additionally, it is recognised that igneous rocks also may contribute directly to basin-related uranium mineral systems as a metal source. Thus, mapping of the distribution of uranium in igneous rocks has the potential to highlight prospective regions for uranium mineralisation at a macro-scale. Geoscience Australia has produced a series of three digital maps showing the uranium content of igneous rocks across Australia, drawing together geochemical and geological datasets from disparate open file sources. Map 1 shows the uranium concentration in whole rock geochemical analyses plotted as point data on a background of igneous rock type, which itself is derived from Geoscience Australia's 1:1 000 000 national surface geology map. Map 2 integrates these datasets, and shows the average uranium content of all intersecting geochemical data point for outcropping individual igneous rock units. In Map 3, a similar approach is employed in mapping the average uranium content of igneous rocks occurring under cover, using interpreted solid geology coverages. Combined, these maps provide a comprehensive picture of the province-scale trends in igneous uranium content across the continent. Using an applied knowledge of processes leading to uranium concentration in magmatic systems, igneous rocks exhibiting a favourable combination of factors are able to be identified for further analysis of prospectivity for uranium mineral systems.

  • Uranium deposits are generally classified into types based on host rock, orebody morphology or structural setting. Widely used schemes contain 14 or more deposit types and numerous sub-types. However, groups of deposit types were formed by similar geological and geochemical processes and likely represent 'variations on a theme'. An alternative scheme is presented that recognises the continuum of possible uranium deposit styles between three families of mineral systems: magmatic-related, 'metamorphic'-related, and basin-related. Formation of uranium deposits in each family involves fluids of three end-member type: magmatic-hydrothermal, 'metamorphic' (including diagenetic waters and fluids reacted with metamorphic rocks at elevated temperatures), and surface-derived fluids such as meteoric waters, seawater, lakewater and groundwater. By better understanding the fundamental geological and geochemical processes involved in ore formation in each family of uranium mineral systems, the most important geological 'symptoms' can be recognised and mapped. This mineral systems approach has been applied to magmatic-related uranium systems in Australia. The predictions of potential suggest that the under-representation of magmatic-related uranium resources relative to other parts of the world with similar geology may be due not to low endowment but to lack of discovery.

  • To assist explorers, Geoscience Australia (GA) has compiled a fact sheet (2006) of products produced by GA related to those commodities (nickel, copper, cobalt, chromium, platinum-group elements, titanium, vanadium) associated with Precambrian mafic-ultramafic rocks in Australia. These products include national review publications (e.g., Nickel sulphide deposits in Australia), reports of metallogenic province studies (Kimberleys, Pilbara, Arunta, Gawler), and various maps, PowerPoint presentations, and digital datasets. Most products can be downloaded free through the www links provided on the fact sheet.

  • The areas included in the geophysical survey, namely the Laloki, Moresby-King and Dubuna leases, are among those held by Mandated Alluvials N.L., and lie in the Astrolabe Mineral Field. The positions of the leases held by the Company are shown in Plate G73-1. Laloki, the main producer of copper, is situated 20 miles by road from Port Moresby, near the junction of Sapphire Creek with the Laloki River. The Bureau was requested by Mandated Alluvials to carry out a geophysical survey in the vicinity of the known deposits and in adjacent areas. Both Laloki and Moresby-King mines has been in production up to the time when the war in New Guinea caused a suspension of operations. During the war the mine workings and much of the plant were completely destroyed. When consideration was given to the best method of reopening the mines it was decided that, if a large enough tonnage or ore could be proved sufficiently close to the surface, it would be most profitable to continue open-cut mining, and possibly install a flotation concentrator to avoid the troubles that had always accompanied smelting. The aim of the geophysical survey was, therefore, to locate a body of ore large enough to justify the adoption of these mining and treatment methods.

  • Report on the activities of the administrative and technical sections in the Katherine-Darwin area, to May, 1954. A brief account is given of geophysical operations. The results of prospecting and development work are summarised.

  • Report on the activities of the administrative and technical sections in the Katherine-Darwin area, to June, 1954. A brief account is given of geological and geophysical operations. The results of prospecting and development work are summarised.

  • The Radioactive Section of the Bureau of Mineral Resources expanded its operations in the Katherine-Darwin Area during this quarter. The staff working in the area has been considerably increased, but more geophysicists are required. Regional geological mapping has commenced for the season and has disclosed one prospect showing radioactivity in the Burrundie district. Detailed geological mapping and radiometric gridding is being done at Burrundie, Brock's Creek, A.B.C. and Adelaide River Prospects.

  • A seismic reflection survey was carried out in the Parish of Darriman, Victoria. The survey was planned to investigate a gravity anomaly, which may be an indication of a structure within the sedimentary section favourable to the accumulation of oil or natural gas. For the most part reflections were exceptionally good, and it was possible to trace one reflecting layer over most of the area. Contouring showed the presence of an anticlinal structure, plunging to the east, but rising and broadening to the west. On the flat crest of the structure, there is probable closure in two places. The thickness of the Tertiary sediments may be a maximum of 6,000 feet, but may be only 3,000 feet on the crest of the structure and 4,000 feet on the flanks.

  • Report on the activities of the administrative and technical sections in the Katherine-Darwin area, to July, 1954. A brief account is given of geological and geophysical operations. The results of prospecting and development work are summarised.

  • Report on the activities of the administrative and technical sections in the Katherine-Darwin area, to August, 1954. A brief account is given of geological and geophysical operations. The results of prospecting and development work are summarised.