The minerals industry presently provides 49% of Australia's export income. Although most of this income is derived from the bulk commodities, the earliest mining in Australia was of precious and base metals. The first major mining boom in Australia, the Victorian gold rush, and later rushes to silver-lead deposits at Broken Hill and gold deposits at Kalgoorlie, laid the foundations of Australia's wealth in the latter half of the 1800s. These mining booms had major consequences in the founding of provincial cities such as Bendigo, Ballarat and Kalgoolie and funding early growth of Melbourne and Perth. These and subsequent mineral discoveries were major drivers in opening up regional and inland Australia, not only for mining, but also for agriculture and tourism. Analysis of major Australian mineral provinces indicate that despite differences in metallogeny and geological setting, these provinces share many common features, including an association with margins of crustal blocks; an association with (inverted) extensional faults, many of which penetrate the crust; a common association with mantle-derived magmas or fluids; a temporal association with plate reconfigurations; localisation of ores by chemical or physical gradients; and an association with major fluid flow caused by either thermal or tectonic events. Major mineral provinces are products of the supercontinent cycle and developed preferentially along the margins of crustal blocks. Localisation of deposits is controlled by the basinal, structural and chemical architecture developed during these processes. Formation of major provinces may be the consequence of unusual processes or events that overprint the supercontinent cycle. The Eastern Goldfields gold province is related to amalgamation of the first supercontinent, Kenorland, and the Australian zinc belt Olympic Cu-Au-U province relates to the first break-up after to GOE. The Victorian goldfields appear to be associated with Au-enriched sources.

The Arunta Region of central Australia is a geologically complex and tectonically longlived terrane which has been subjected to several periods of magmatism. SHRIMP U-Pb dating of zircons by Claoué-Long and Hoatson (2005) constrain the major mafic magmatic events to the dominantly tholeiitic ~1810-1800 Ma Stafford Event, the ~1790-1770 Ma Yambah Event, ~1690 Ma Strangways Event, ~1635 Ma Liebig Event, and a much younger event of probable early Palaeozoic age. A further event (Teapot) at ~1135 Ma has alkaline-ultramafic affinities. Field-relationships and mineralisation-features of the intrusions are described by Hoatson and Stewart (2001), and Hoatson et al. (2005). The intrusions form large homogeneous mafic granulite and gabbroic bodies, stacked sequences of high-level sills, small pods, laterally extensive amphibolite sheets, and relatively undeformed ultramafic plugs. The intrusions occur in proximity to major province-wide faults where differential movements have resulted in the exposure of the intrusions from crustal depths ranging from ~5 km to ~25 km. Metamorphic grades range from granulite to sub-amphibolite facies. Chilled and contaminated margins and net-vein complexes resulting from the commingling of mafic and felsic magmas indicate that most intrusions crystallised in situ and were not tectonically emplaced. <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>

Presented at the Evolution and metallogenesis of the North Australian Craton Conference, 20-22 June 2006, Alice Springs. Strikingly similar geological histories and metal endowments support the view that the Broken Hill (Curnamona craton) and Mt Isa regions were once contiguous, or at least formed part of a single continuous Zn-Pb and/or IOCG mineral province, during the late Palaeoproterozoic-early Mesoproterozoic (Giles et al., 2004). Pb model ages for major Zn-Pb deposits like Broken Hill and Cannington (1675 Ma and 1665 Ma respectively) are comparable (Carr et al., 2004) and high grade metasedimentary rocks hosting these deposits are thought to have been deposited at about the same time (ca 1690-1670 Ma) in either an intra-continental rift or a back-arc extensional environment (e.g., Blake, 1987; Walters and Bailey 1998; Betts et al., 2003). High grade deformation and metamorphism at 1580-1600 Ma (e.g., Page and Sweet, 1998; Page et al. 2004) preclude unequivocal identification of the original ore-forming environment in both cases, although clues to the tectonic setting and kinematic framework are still preserved in less intensely metamorphosed rocks of equivalent age in the Mount Isa Western Succession. The Western Succession rocks developed over a 200-Myr period from 1.8 Ga to 1.6 Ga (Blake, 1987) and, thus, overlap in age with five major tectonothermal events (Claoué-Long, 2003; Scrimgeour, 2005) recognised in the Arunta-Tanami region of the NAC. Major events identified at 1810 Ma and 1770 Ma (Stafford and Yambah), 1730-1700 Ma (Strangways), ~ 1640 Ma (Leibig) and 1560-1590 Ma (Chewings) in the NAC also find expression in the Mount Isa and Broken Hill regions (Page et al., 2000; Neumann et al., 2006), inviting speculation that the crustal processes and geodynamic framework inferred for these two regions are equally pertinent to the mineral provinces in the southern and eastern NAC.

The global distribution of mineral deposits in cratons, belts and districts shows that they are not equally and uniformly endowed with metal. Some cratons are highly fertile (e.g. Yilgarn Craton for Archaean greenstone gold and nickel) and there are those which are almost barren (e.g. Archaen greenstone belts in the Pilbara Craton). Within belts the distribution is equally non-uniform. For instance more than 80% of gold resources in the Yilgarn are concentrated in the Kalgoorlie Terrane of the Eastern Goldfields. At a first level the total endowment can be used to compare mineralised belts and districts, however the distribution of deposit sizes in them can provide a second level constraint on their fertility, in particular the nature and intensity of metal accumulation versus metal dispersion. More enigmatic from this point of view are belts and districts in which the total metal endowment is contained in one or two giant and/or super-giant deposits, such as the Broken Hill in New South Wales, Norilsk-Talnakh in Western Siberia, and Olympic Dam in South Australia. These mjaor deposits represent single "bull elephants" in an "elephant country". Cumulative frequency distribution curves of metals of major mineralized cratons, belts and districts are used to compare the nature of their metal endowment. The analysis shows that the curves of "elephant-bearing" belts and districts are remarkably different from those of "average" belts and districts, and that regional and/or district scale geological factors could have played a significant role in controlling metal endowment. A comparison of curves for belts and districts with similar endowment can be used to assess potential for yet to be discovered deposits and to assess their relative size.

Presented at the Evolution and metallogenesis of the North Australian Craton Conference, 20-22 June 2006, Alice Springs. The Pine Creek Orogen (PCO) is part of the North Australian Craton and is correlated with other Palaeoproterozoic domains of northern Australia. Archaean (>2.5 Ga - 2.7 Ga) granite and metamorphics are overlain by Palaeoproterozoic strata comprising sandstone, mudstone, and minor carbonates and volcanics. Its age is constrained between 2.5 Ga and 1.86 Ga, and the succession is divided into two supergroups. The older Woodcutters Supergroup comprises <2.5 Ga to 2.02 Ga arenites, stromatolitic dolostone, and pyritic carbonaceous shale. The younger Cosmo Supergroup comprises BIF, mudstone, and tuff, succeeded by a monotonous flysch sequence. Zircons from the tuff beds provided an age of 1863 Ma, confirming a major depositional break of about 150 million years. <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>

Presented at the Evolution and metallogenesis of the North Australian Craton Conference, 20-22 June 2006, Alice Springs. The Tanami Region (TANAMI and THE GRANITES 1:250 000 map sheet areas) is centrally located within the North Australian Craton and contains a gold-mineralised Palaeoproterozoic orogenic sequence. Page et al (1995) postulated Neo-Archaean granitic gneiss as basement to the Tanami Group, although no lower sedimentary contact has been observed. <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>

The iron-oxide copper-gold or IOCG deposit class includes a broad range of mineralisation styles ? so broad that debate continues on which deposits are members of the class. These epigenetic magnetite- and/or hematite-rich deposits range in age from late Archaean (e.g., Salobo, Brazil), through Proterozoic (e.g., Olympic Dam, Ernest Henry, Tennant Creek district), to Mesozoic (e.g., Candelaria). Rather than focussing on the boundaries in deposit classification, let?s consider the `constants? in observed characteristics and processes that recur within regions of major IOCG deposits. This will allow an improved understanding of the local `variables? that result in such diverse deposits. Four `constants? are recognised in the major Australian IOCG districts. First, in each there is evidence for a major regional thermal event broadly coeval with IOCG formation, represented by low to medium grade metamorphism, and/or mafic intrusions, and/or I- or A-type granitoids. Coeval volcanics are preserved in some districts. However, a gap remains in our understanding of the role of magmas in IOCG genesis. Second, the host supracrustal sequences were relatively Fe-rich prior to IOCG-related hydrothermal activity, but contain only minor or no reduced carbon-bearing strata, at least at the crustal levels now exposed. Evaporites, basalts and regional-scale sodic-calcic alteration occur in some but not all major IOCG districts. Third, trans-crustal sutures are present in regions of the major IOCG deposits, linked to networks of brittle-ductile shears or brittle faults that were active during the regional thermal event(s). Although new studies are investigating the crustal architecture of some IOCG ore-forming systems (e.g., seismic surveys near Cloncurry and Olympic Dam), 3D models with predictive capability have yet to be developed. Fourth, two fundamentally different fluids are recognised in IOCG districts, whose variable interaction (mixing and fluid-rock reaction) arguably gives rise to many of the mineralogical and geochemical variations among IOCG deposits. One fluid was high salinity, ~350-500?C, intermediate oxidation state (magnetite-pyrite-stable) or was locally reduced, and transported Fe, K, Cu, Ba, Mn, REE, and by inference Au and H2S > SO42-. The second fluid was lower salinity, ~150-250?C, oxidized (hematite-pyrite-stable, SO42- > H2S) to very oxidised, possibly carried some Au, Cu and U, and is most evident where IOCG deposits developed at shallow crustal levels. Additionally, many IOCG mineralising systems contain CO2-rich fluids. The key `variables? giving rise to differences in IOCG deposits within and between districts are: crustal depths of ore formation (including extent of `telescoping? of shallow on deeper styles), and local host rock types which are very diverse. Variations in depth of formation lead to a spectrum of structural styles (e.g., breccia at shallow levels, shear-hosted styles at deeper levels), and alteration and ore mineral assemblages (e.g., hematite-bearing at shallower levels; magnetite-bearing at deeper levels). Acknowledgements: Published with the permission of the Executive Director, Geoscience Australia. Discussions with colleagues at Geoscience Australia including Evgeniy Bastrakov, David Huston, Patrick Lyons, Ollie Raymond, Lesley Wyborn, and with John Walshe, and Douglas Haynes are acknowledged.

Shared geological and geochemical processes are involved in the formation of particular groups of uranium deposits. Three families of uranium mineral systems are recognised: magmatic-, metamorphic- and basin-related. End-member fluids in each family are magmatic-hydrothermal, 'metamorphic' (including fluids reacted with metamorphic rocks at elevated temperatures), and surficial fluids such as meteoric water, lake water and seawater. Most well known uranium deposit types can be accommodated within this tripartite framework, which explicitly allows for hybrid deposit types.

Deep seismic reflection data across the Western Lachlan Orogen of southeast Australia have provided important insights into crustal-scale fluid pathways and possible source rocks across one of the world's richest orogenic gold provinces. The profiles span three of Victoria's most productive structural zones: the Stawell, Bendigo and Melbourne zones. Zone-scale variations in the age and style of gold deposits are reflected by changes in crustal structure and composition as revealed by the seismic data. The Stawell and Bendigo structural zones can be broadly divided into a lower region of interlayered meta-volcanic and meta-sedimentary rocks and an upper region of meta-sedimentary rocks. First-order faults appear to have accommodated large scale crustal thickening down to the lower crust. The bilateral distribution of gold production in the Stawell and Bendigo zones is related to the V-shaped crustal-scale geometry of the two zones in cross-section. Major first-order faults, like the east dipping Moyston Fault and a set of west dipping listric faults, were major fluid conduits during the most important gold event at 440 Ma. These first-order faults converge in the mid and lower crust in a region beneath the western Bendigo Zone where mafic volcanic rocks are identified as a likely common source of metamorphic fluids and gold during the main 440 Ma mineralizing event.

Presented at the Evolution and metallogenesis of the North Australian Craton Conference, 20-22 June 2006, Alice Springs. The Pine Creek Orogen forms the northern margin of the North Australian Craton (Plumb, 1979). Broadly, it comprises sequences of carbonaceous, clastic, and volcanogenic sediments deposited upon rifted Archaean crystalline basement, which were subsequently deformed, metamorphosed, and intruded by syn- to post-orogenic granitoids and mafic bodies. The Pine Creek Orogen can be divided into three distinct domains, reflecting different deformational, metamorphic, and stratigraphic attributes (Worden et al., in review). These are, from west to east, the Litchfield Domain, the Central Domain, and the Nimbuwah Domain. <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>