No abstract available

No abstract available

Abundant, micron-scale, spherical aggregates of 2?5 nm diameter sphalerite (ZnS) particles formed within natural biofilms dominated by relatively aerotolerant sulfate-reducing bacteria of the family Desulfobacteriaceae. The biofilm zinc concentration is about 106 times that of associated groundwater (0.09 ? 1.1 ppm Zn). Sphalerite also concentrates arsenic (0.01 wt %) and selenium (0.004 wt %). The almost monomineralic product results from buffering of sulfide concentrations at low values by sphalerite precipitation. These results show how microbes control metal concentrations in groundwater and wetland-based remediation systems and suggest biological routes for formation of some low temperature ZnS deposits.

Legacy product - no abstract available

The paper reveiws metallogenic evolution of Australia. A comparison between Archaean, Proterozoic and Phanerozoic metallogeny reveals that in general there exist more similarities between the Archaean and the Phanerozoic that those between the Archaean and the Proterozoic and between the Proterozoic and the Phanerozoic metallogeny. The paper argues that the contribution of plate tectonic processes in the geological evoultion and metallogeny of Australian Proterozoic need revaluation for assessing mineral potetnial of deposit styles which are traditionally considered to be not important but large deposits of each are known to exist in the Proterozoic elsewhere.

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>

This address was presented at the 2008 Australian Nickel Conference held in Perth, 22-23 October 2008. Geoscience Australia has released a detailed, web-based colour map (at 1:5 000 000 and 1:10 000 000 scales) 'Australian Proterozoic Mafic-Ultramafic Magmatic Events (Sheets 1 and 2)'. This new map is the third and final component of the Proterozoic magmatic event series that show, for the first time, the geographic extent and age relationships of Proterozoic mafic and ultramafic rocks, and associated mineral deposits throughout the continent. The maps (`Proterozoic mafic-ultramafic magmatic events of Western Australia' and 'A Synthesis of Australian Proterozoic Mafic-Ultramafic Magmatic Events. Part 2: Northern Territory and South Australia') were produced in close collaboration with the State and Northern Territory geological surveys.

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.

To assist the mining industry during the current buoyant times of historically high nickel and platinum-group element prices, Geoscience Australia has produced two web-based map sheets (at 1:5 million and 1:10 million scales) that show the spatial distribution of Proterozoic (2500 Ma to 545 Ma) mafic-ultramafic magmatic events in Australia. The maps illustrate for the first time, the continental extent and age relationships of Proterozoic mafic and ultramafic rocks and their associated mineral deposits. These rocks have been assigned to thirty Magmatic Events (ME) that range in age from the Early Palaeoproterozoic ~2455 Ma (ME 1) to the Early Cambrian ~520 Ma (ME 30). Record 2008/15 (Geocat 66624) is a user guide for the `Australian Proterozoic Mafic-Ultramafic Magmatic Events' map (Geocat 66114). It compiles all the geological and geochronological data that underpins the information portrayed on the map. The key objectives of this user guide are to: - summarise the scope, scientific rationale, and methodology of the study; - describe the digital datasets (e.g., solid geology, geological province, geochronology, mineral resources, geophysics, etc) that underpin the information portrayed on the maps; and - document the attribution data and publications used for characterising and assigning magmatic events to the Proterozoic mafic-ultramafic units. <h3>Related products:</h3><a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&amp;catno=66114">Australian Proterozoic Mafic-Ultramafic Magmatic Events: Map Sheets 1 and 2</a> <a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&amp;catno=70461">Proterozoic Mafic-Ultramafic Magmatic Events Resource Package</a> <a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&amp;catno=69347">Archean Mafic-Ultramafic Magmatic Events Resource Package</a> <a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&amp;catno=69935">Guide to using the Australian Archean Mafic-Ultramafic Magmatic Events Map</a> <a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&amp;catno=69213">Proterozoic Large Igneous Provinces: Map Sheets 1 and 2</a> <a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&amp;catno=70008">Guide to using the Map of Australian Proterozoic Large Igneous Provinces</a>

As part of the 11th SGA Biennial meeting in Townsville, Australia, the Organising Committee is offering a series of field trips to examine the geology and setting of important mineral provinces in Australia, New Zealand and Papua New Guinea. The purpose of this short article is to provide an overview of the metallogeny of Australia, which is considered within the framework of the geological evolution of the Australian continent.