Currently, many conflicting plate reconstructions and tectonic models have been proposed for the Proterozoic evolution of Australia. Geophysical data, including potential field (gravity and magnetic) and deep seismic reflection profiles can be used to help constrain these models. Potential field images of the continent show distinct changes in the orientations of geophysical trends; defining key boundaries, some of which have been interpreted to represent the locations of ancient plate boundaries. Deep seismic reflection profiles now cross many of the Proterozoic provinces in Australia, and can be used to define the locations of the boundaries between adjacent provinces. In north Queensland, a suture defining the eastern limit of the Mount Isa Province and a fossil subduction zone farther to the east have been imaged. In southern Australia, in the Gawler-Curnamona region, three sutures separating discrete pieces of crust have been imaged, suggesting eastward growth of this region during the Proterozoic. In central Australia, at least five sutures are recognised, implying the accretion of continental slivers before final amalgamation between the North Australian Craton and the South Australian Craton. In Western Australia, three probable sutures suggest progressive accretion of continental slivers onto the southern margin of the Pilbara Craton to build the West Australian Craton. In summary, interpretations of the deep seismic reflection profiles used in conjunction with potential field images are providing constraints on the three dimensional architecture of Australia, including the locations of ancient plate boundaries, which will help to constrain tectonic models and plate reconstructions for the evolution of Proterozoic Australia.

The Capricorn Orogen in Western Australia records the punctuated Proterozoic assembly of the Pilbara and Yilgarn Cratons to form the West Australian Craton, and over one billion years of subsequent intracratonic reworking and basin formation. The orogen is over 1000 km long, and includes the passive margin deposits of both the Pilbara and Yilgarn Cratons, variably deformed and metamorphosed granitic and metasedimentary rocks of the Gascoyne Province, and very low- to low-grade metasedimentary rocks that overly these three tectonic units. Several mineral systems have been recognized in the orogen, including the world-class hematite iron-ore deposits of the Hamersley Basin. Other deposits include volcanic-hosted metal sulphide (VHMS) copper-gold deposits, orogenic lode-gold mineralization, various intrusion- and shear zone related base metal, tungsten, rare earth element, uranium and rare-metal deposits, and sediment hosted lead-copper-zinc mineralization. A recent 581 km long vibroseis-source, deep crustal seismic survey across the Capricon Orogen, has provided critical information on the architecture and geological evolution of the orogen. The transect has identified several distinct crustal terranes, each separated by moderately south-dipping suture zones, as well as other major structures that cut through the crust to the mantle. This improved understanding of the Capricorn Orogen has shown that many of the mineral occurrences within the orogen are spatially associated with these crustal-scale structures, which appear to have concentrated fluids, energy, and metals into specific sites in the Capricorn Orogen crust.

The Georgina-Arunta deep seismic reflection line (09GA-GA1) has provided an image of the entire crust in this part of central Australia. At a first approximation, beneath the Neoproterozoic-Devonian sedimentary basins, the crust can be divided into four distinct regions, namely, the Aileron, Irindina and Davenport Provinces, and the Ooratippra Seismic Province. Each of these regions is separated from each other by major, crustal-scale faults. The observed crustal architecture has implications for geodynamic models for the evolution of the region, implying amalgamation of these crustal blocks in the Paleoproterozoic and major shortening and basin inversion in the Paleozoic.

Collation of extended abstracts presented at the pmd*CRC conference 11-12 June 2008

The secular distribution of zinc deposits is pulsed and related to changes in Earth processes and conditions, including the supercontinent cycle and oxygenation of the atmosphere and hydrosphere. Deposits hosted by volcanic successions formed during the assembly of supercontinents along convergent margins, probably as the consequence of high heat flow and a greater likelihood that such tectonic systems are preserved. Siliciclastic-hosted and carbonate-hosted deposits post-date the first oxygenation event as fluids that formed these deposits were oxidized. Siliciclastic-hosted deposits formed both during assembly and breakup of supercontinents, whereas carbonate-hosted deposits formed during supercontinent or microplate assembly.

The western two-thirds of Australia is underlain by Precambrian rocks that are divisible into three Archean to Paleoproterozoic cratons, the West Australian, North Australian and South Australian cratons, separated by Paleoproterozoic to Mesoproterozoic orogens. The temporal and spatial record of Proterozoic rock units and orogenic events documents accretion and assembly of Precambrian, proto-Australia. The Archean Yilgarn and Pilbara cratons were assembled into the West Australian Craton along the Capricorn Orogen during the late Paleoproterozoic (2000 Ma) Glenburgh Orogeny, which then combined with the North Australian Craton along the Rudall Orogen during the 1800-1765 Ma, Yapungku Orogeny. Prior to about 1500 Ma the North and South Australian cratons show a similar geological history and are herein assumed to have evolved as a single entity, termed the North-South Australian Craton. It was bounded throughout most of the late Paleoproterozoic to earliest Mesoproterozoic by subduction zones along its south western and north eastern margins such that much of the craton occupied an upper plate, back arc basin environment. After ~1500 Ma the craton differentiated into the North Australian and South Australian cratons through rotation and lateral translation of the latter, resulting in convergence and collisional suturing with the West Australian craton along the 1345-1140 Ma Albany-Fraser Orogen. The Pinjarra Orogen developed along the margin of the West Australian Craton and records late Mesoproterozoic to Neoproterozoic strike-slip juxtaposition of India within an assembling Gondwana. The Neoproterozoic record of the Terra Australis Orogen, which extends along the eastern side of Precambrian Australia, records rifting and continental breakup within the supercontinent of Rodinia. Australian Proterozoic rocks host significant mineral resources, including world class banded iron-formations in the West Australian craton (Hamersley), and iron oxide copper gold deposits (Olympic Dam), Pb-Zn-Ag systems (Mount Isa and Broken Hill) and uranium deposits in the North-South Australian Craton.

Palaeoproterozoic to Mesoproterozoic Geology of North Queensland IW Withnall1, NL Neumann2 & A Lambeck2 1 Geological Survey of Queensland, Department of Employment, Economic Development and Innovation 2 Geoscience Australia The Palaeoproterozoic to Mesoproterozoic rocks of north Queensland that crop out in the Georgetown, Yambo and Coen Inliers (Figure 1) are the most easterly rocks of this age in Australia. They are important to an understanding of the evolution of the continent and possible configurations of Rodinia. Most models for the evolution of the North Australian Craton assume Georgetown and the other inliers to be a part of it, although usually have given little thought to how they might fit in the model.

As part of the Australian Government's Onshore Energy Security Program and the Queensland Government's Smart Mining and Smart Exploration initiatives to support energy security and mineral exploration, a deep seismic reflection survey was conducted in 2007 to establish the architecture and geodynamic framework of north Queensland. With additional support from AuScope, nearly 1400 km of seismic data were acquired along four lines, extending from near Cloncurry in the west to almost the Queensland coast. 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).

New geochronological data combined with existing data suggest that the Neoproterozoic period in Australia was reasonably well mineralised, with two major periods of mineralisation: (1) 850-800 Ma sediment-hosted Cu, unconformity U, and diamond deposits, and (2) 650-630 Ma epigenetic Au-Cu deposits. The early period appears to be associated with extension related to initiation of Rodinia break-up, whereas the geodynamic setting of the latter, more restricted, event is unclear.

Increasingly, positioning applications in hazard assessment, mining, agriculture, construction, emergency, land, utility and asset management have a demonstrated need for centimetre level or better geodetic infrastructure. However, the geodetic infrastructure in the Asia-Pacific, when compared to other geographical regions, can be generally assessed as being sparse, inhomogeneous in accuracy, infrequently realised and difficult to access. Correspondingly, it has become increasingly clear that the Asia-Pacific infrastructure is below the standard that is now available in other regions, such as Europe and the Americas, and it represents a loss in competitive advantage. The Permanent Committee for GIS Infrastructure Asia-Pacific (PCGIAP) and the International Association of Geodesy (IAG) have made some progress in developing the Asia-Pacific geodetic infrastructure; however, it can still be characterised as being a work in progress. In this presentation, we review recent efforts to improve the region's geodetic infrastructure. Specifically, we focus on crustal deformation and show results from the Asia-Pacific component of the International Association of Geodesy (IAG) working group on regional velocity fields, which includes crustal velocity estimates for over 1200 stations. This velocity field incorporates solutions derived from Continuous GPS (CGPS) data, episodic campaign based data and also velocity-only information where precise coordinates are not available. Our combination method, including our approach of incorporating velocity-only information expressed in a variety of reference frames, such as plate-fixed frames, will be overviewed. Finally, we will review the key elements of the Asia-Pacific Reference Frame (APREF) initiative, which will create and maintain a modern regional geodetic framework based on continuous GNSS data.