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  • 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>

  • As part of the Australian Government's Onshore Energy Security Program and the Queensland Government's Smart Mining and Smart Exploration initiatives, deep seismic reflection surveys were conducted in North Queensland to establish the architecture and geodynamic framework of this area in 2006 (Mt Isa Survey; also involving OZ Minerals and pmd*CRC) and 2007 (Cloncurry-Georgetown-Charters Towers Survey; also involving AuScope). Nearly 2300 line km of seismic data were acquired during these surveys. Geochemical, geochronological and complementary geophysical studies were undertaken in support of the seismic acquisition. Overviews of the geology of North Queensland and more detailed descriptions and the results of these surveys are presented in Hutton et al. (2009a, b), Korsch et al. (2009a), Withnall et al. (2009a, b), Henderson and Withnall (2009), and Henderson et al. (2009). The purpose here is to use the new geodynamic insights inferred from these data to provide comments on the large-scale geodynamic controls on energy and other mineral potential in North Queensland. This contribution draws on geodynamic and metallogenic overviews presented by Korsch et al. (2009b) and Huston et al. (2009)

  • Presented at the Evolution and metallogenesis of the North Australian Craton Conference, 20-22 June 2006, Alice Springs. Over a half (570) of the known uranium occurrences in Australia are located in the North Australian Craton and the overlying Ngalia, Amadeus, and McArthur River basins. These occurrences include 43 uranium deposits with recorded resources. The uranium occurrences and deposits show a general spatial relationship to uranium-enriched felsic igneous rocks. The total uranium resource (production + resources) of the North Australian Craton and the overlying basins amount to about 510,000 t U3O8. The bulk of these resources are accounted for by the following: unconformity type in the Pine Creek Orogen (~420,000 t U3O8), sandstone uranium (~36,000 t U3O8) in the McArthur, Amadeus and Ngalia Basins, metasomatite (~38,000 t U3O8) and metamorphic deposits of the Mt Isa Orogen, and calcrete deposits in Arunta. <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>

  • As part of the North Pilbara NGMA Project, AGSO (now Geoscience Australia), together with Newcastle University and the Geological Survey of Western Australia (GSWA), have been conducting a research program to document the geological setting, characteristics and genesis of Au deposits of the North Pilbara Terrane. This record summarises some results of this research program. This research has concentrated on turbidite-hosted lode Au deposits in the Indee and Nullagine areas as well as basalt and ultramafic-hosted deposits in the Mt York-Lynas Find area. In addition to these areas, AGSO's research also concentrated on epithermal deposits in the Indee area, and less detailed studies were undertaken on lode Au deposits at Gold Show Hill and Klondyke. This research program was designed to complement recent (e.g., Neumayr et al. [1993; 1998] on the York deposits and Zegers [1996] on the Bamboo Creek deposits) and ongoing (e.g., D. Baker, University of Newcastle] at Mt York-Lynas Find) programs conducted at the other institutions. This Pilbara Gold Record is supported by an extensive GIS dataset, providing many new digital data sets, including a number of variations of the magnetics, gravity, and gamma-ray spectrometry. A solid geology map, and derivative maps, mineral deposits, geological events, and Landsat 5-TM provide additional views. This data set complements the 1:1.5 Million scale colour atlas (Blewett et al., 2000).

  • Orogenesis in Phanerozoic systems is rapid, diachronous, episodic, and involves the switching of tectonic modes (extension-compression). In contrast, many Archaean orogens have traditionally been viewed as having developed by relatively simple, long-lived, mono-mode deformational processes. New results, however, reveal that the late Archaean eastern Yilgarn Craton (EYC) evolved episodically and rapidly, with a diachronous series of approximately E?W coaxial switches in tectonic mode. Tectonic mode switching changed stress regimes and resulted in the development of `late basins?, the emplacement of granites, and early orogenic gold mineralisation diachronously from east to west (NE?SW). Fluids were driven from the lower crust (and below) via large-scale crustal imbricating thrust faults. These fluids promoted the passage of a compression-extension couplet along a basal detachment by successively `lubricating? faults (preparing the ground), and facilitating a propagating wave of foreland surge (D2a) and hinterland extension (D2E) followed by inversion, uplift and annealing (D2b). In this way, orogenic Au and westward orogenic surge with associated tectonic mode switches are linked. We predict that the compres-sion-extension couplets and early orogenic gold mineralisation propagated from the east to the west diachronously at a rate of ~3-5 m.y. between domains from ~2670 Ma to ~2650 Ma. Multiple mineralising episodes are also a predicted consequence of the orogenic surge model.

  • Precambrian layered mafic-ultramafic intrusions in Australia have recently generated considerable exploration interest for their platinum-group element (PGE: Pt, Pd, Rh, Ru, Os, Ir) and Ni-Cu-Co potential. Exploration has been stimulated by the discovery of potential world-class deposits (Voisey?s Bay, Canada; west Musgraves), high metal prices (notably Pd, Pt, and Rh), and a perception that many favourable intrusions are under-explored for different styles of orthomagmatic and hydrothermal mineralisation. Despite the renewed interest, Ni production associated with layered intrusions accounts for only 3% of Australia?s Ni production, and PGE production is currently restricted to the Archaean komatiitic-volcanic associations of the Yilgarn Craton. Exploration programs (see Hoatson & Blake 2000) for Precambrian layered intrusions vary considerably for different styles of precious- and base-metal mineralisation. The four styles of mineralisation considered here are believed to have the greatest potential in the following major orogenic domains: (1) Stratabound PGE-bearing sulphide layers: Yilgarn Craton, Pilbara Craton, Musgrave Block, Gawler Craton; (2) Stratabound PGE-bearing chromitite layers: Halls Creek Orogen, Albany?Fraser Orogen, Yilgarn Craton; (3) Basal segregations of Ni-Cu-Co?PGE sulphides: Musgrave Block, Pilbara Craton, Yilgarn Craton, Halls Creek Orogen, Arunta Block, Gawler Craton; and (4) Hydrothermal PGE remobilisation: Pilbara Craton, Arunta Block, Halls Creek Orogen, Yilgarn Craton, Musgrave Block, Gawler Craton. During the exploration of layered intrusions it is important not to be `blinkered? to a particular model, but to maintain a flexible innovative approach and consider different styles of orthomagmatic and hydrothermal mineralisation at different stratigraphic levels in the intrusion. It should also be borne in mind that it took more than 20 years of intensive exploration to define the J-M Reef of the Stillwater Complex, and it was not until the 1990s that a significant Au-PGE layer (Platinova Reef) was found in the Skaergaard Intrusion, East Greenland?an intrusion which has been investigated in great detail for more than 60 years.

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