Presented at the Evolution and metallogenesis of the North Australian Craton Conference, 20-22 June 2006, Alice Springs. The southern Arunta region contains a number of small (<5 Mt) Zn-Cu-Pb (Ag-Au) deposits. Although none of these deposits are economic, they do indicate a moderate level of base-metal potential for this region. Most of these deposits are located in the Strangways Range, which forms part of the Aileron Province. These deposits were classified as Oonagalabi-type deposits by Warren & Shaw (1985), citing similarities in metal assemblages, alteration assemblages, and host units, and interpreted as volcanic-hosted massive sulphide (VHMS) deposits. More detailed geological mapping and geochemical and geochronological data suggest that the Oonagalabi group should be subdivided further into three types, the Utnalanama-type, the re-defined Oonagalabi-type and the Johnnies-type (Hussey et al., 2005). <p>Related product:<a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&amp;catno=64764">Evolution and metallogenesis of the North Australian Craton Conference Abstracts</p>

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An overview of mineral exploration within Australia for the year 2000.

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An interactive CD-ROM showing mineral exploration in Australia. Commodities addressed are gold, copper, zinc, nickel, diamonds, mineral sands, iron ore, coal by mine and deposit locations, size, age and deposit type.

Package comprises a digital compilation of regional mapping of Bathurst (SI5508) 1:250 000 map by AGSO and NSW Department of Mineral Resources, under NGMA from 1991 to 1996.

Detailed analysis and modeling of regional gravity and magnetic datasets from the Stuart Shelf around the Olympic Dam iron oxide-copper-gold (IOCG) deposit, constrained by geological observations from deep drillcores, show that the eastern Gawler Craton at 1.61-1.59 Ga consisted of an Archean core with two volumes of supracrustal successions stepping out eastward from it. This pattern is consistent with that displayed on the Eyre Peninsula. Detailed models of potential-field data show no evidence for the presence of widespread mafic rocks or extensional basin systems developed immediately prior to, or during, IOCG mineralization. The high intrusive level, and geometry of Hiltaba Suite plutons emplaced immediately prior to IOCG mineralization is difficult to explain in terms of a genetic association with mantle plumes, continental extension, or rifting. Instead, the tectonic setting inferred from the basement architecture during mineralization is one of low-strain compression, based on geometric considerations. A case can be made for mild extension in a localized accommodation zone during emplacement of the Hiltaba Suite and Gawler Range Volcanics, in an overall orogenic setting with northwest-southeast directed tectonic transport in present coordinates. An IOCG minerals system produced during low-strain compression is consistent with maximum rates and volumes of fluid flow in the upper crust, and access of these fluids to a variety of basement rock types to buffer metal-scavenging fluids. This fluid-driving mechanism does not require, or implicate, a genetic role for regional mafic magmatism and volcanism synchronous with IOCG mineralization. The approach used in this study is generally applicable to exploration for IOCG systems, and other mineral systems in covered terranes that have distinctive geophysical signatures resulting from redox fluid-wallrock geochemical reactions.

The magnitude of systematic uncertainties inherent in comparisons of Proterozoic 40Ar/39Ar- and U-Pb-based ages is illustrated via a consideration of age constraints on two contrasting styles of Palaeoproterozoic mineralization in northern Australia. Published 40Ar/39Ar ages for Au-Cu-Bi-mineralization in the Tennant Creek region range from1825 to 1829 Ma, apparently younger than the timing of deformation bracketed by 207Pb/206Pb zircon ages of igneous rocks at ~1850 Ma. Despite this apparent age offset, propagation of systematic uncertainties in the 40Ar/39Ar ages shows that they are indistinguishable from the ~1850Ma zircon ages. Recalculation using revised estimates of the 40K decay constant and age of the 40Ar/39Ar standard shifts the 40Ar/39Ar ages to 1847-1851 Ma, in excellent agreement with 207Pb/206Pb zircon ages from Tennant Supersuite igneous rocks and with local geological constraints. To the south of Tennant Creek, in the Davenport Ranges, numerous smallWprospects have been interpreted to be coeval with post-tectonic granites of the Devils Suite at ~1710-1720 Ma. New 40Ar/39Ar ages from muscovite selvages on wolframite-bearing veins range from 1697 to 1703 Ma. These ages shift to 1711 to 1717Ma when recalculated using revised estimates for 40K decay constant and age of standard material, bringing them into agreement with existing 207Pb/206Pb zircon ages for Devils Suite granitoids, and consistent with field and geochemical interpretations. These examples highlight the importance of considering systematic sources of uncertainty when comparing radiometric ages determined via different isotopic methods, particularly in the Proterozoic and Archean parts of the timescale. Ongoingwork to calibrate the 40Ar/39Ar and U-Pb-based timescales will further enhance the application of multiple isotopic methods to constrain geological processes.

Uranium mineralization at Coronation Hill is associated with rhyolitic rocks of Upper Proterozoic and sediments of Lower Proterozoic Age. The mineralization at and near the surface is in the form of Autunite and Torbernite; it occurs in a zone of strong fracturing, which effects rocks of both Lower and Upper Proterozoic age. Rubble and soil covers most of the area of interest at Coronation Hill and openings available to date do not allow a full appreciation of the geology of the prospect. A preliminary programme of diamond drilling is recommended to test and prospect and further testing should be guided by such information as is obtained from this drilling. The discovery of uranium mineralization in volcanic rocks of Upper Proterozoic age at Coronation Hill opens up an entirely new province for exploration for uranium in the Katherine-Darwin region of the Northern Territory. The linear belt of fracturing, the South Alligator Fault Zone, on which the Coronation Hill is situated, suggests an obvious zone to which future prospecting effort should be guided.

Geophysical surveys of the magnetite deposits of Australian Magnetite Pty. Ltd. at Gulgong were made by the Bureau in 1952 and 1953, and revealed that the Tallawang deposit was the most important one. The present report gives the results of a detailed magnetic survey which was made over this deposit in August, 1953. Results show that three concentrations of very strongly magnetic material exist within the Tallawang deposit. The southern concentration is unlikely to contain considerable reserves beyond those in sight. The central concentration has been partly worked and could yield reserves of ore from the west wall of the quarry. The northern concentration, which has not been worked, could yield limited reserves. It is shown that the deposit, as a whole, pitches northwards. Some exploratory drilling is recommended on each of the three concentrations.