Uraninite dating of the Kintyre deposit and Rossing South prospect using electron probe chemical U-Th-Pb technique.

AGSO's northwest Australian margin project (NWAM) aims to provide a high level understanding of the geological framework of the entire northwest margin of the continent, with particular emphasis on the crustal and basin architecture. The following studies are currently addressing these objectives: 1) ArcView GIS, 2) Potential field and bathymetric grids (2nd version), 3) Regional deep seismic re-interpretation, and 4) Ocean-bottom seismograph velocity models.

The eastern Yilgarn Craton (EYC) of Western Australia is Australia's premier gold and nickel province, and has been the focus of geological investigations for over a century. Geoscience Australia, in conjunction with partners in the Predictive Mineral Discovery Cooperative Research Centre conducted a series of projects between 2001 and 2008 (Y4 project team, 2008). This article summarises the highlights and new findings from the research, many of which challenge previous paradigms on the tectonics and architecture, as well as the relationship of gold to structure, magmatism and metamorphism. Although a Yilgarn-based study, the results have general implications for other Archaean terranes.

Palaeogrographic analysis of the Early Cretaceous South Perth Supersequence.

In the brief period 2005-2010, geothermal energy showed rapid growth in Australia with many tenements being taken up, significant exploration activities and a number of very deep wells drilled. Since that time, despite world-leading technical success, expenditure, activity, tenement holdings and personnel numbers have decreased markedly. Success has been achieved with the generation of electricity by Geodynamics Ltd at Innamincka, and the creation of a geothermal reservoir by Petratherm Ltd at Paralana. This article examines why this decline has occurred, and looks at the place of geothermal energy in Australia's Clean Energy Future.

In 2010 the UN General Assembly appointed a Group of Experts to carry out the first cycle of the Regular Process from 2010 to 2014. The immediate tasks for the Group of Experts include preparing a draft outline for the First Global Integrated Marine Assessment (the Assessment) and to design a process for drafting and reviewing it. Producing the Assessment will be a major undertaking that will have to involve many hundreds of marine experts from around the world in order to succeed. The purpose of this paper is to describe the rationale behind the draft outline for the Assessment and to explain the process envisaged for producing it by the 2014 deadline. It is emphasised that the Assessment outline is a work in progress and that amendments will be made prior to the commencement of its drafting.

A defining characteristic of the seabed is the proportion that is hard, or immobile. For marine ecosystems, hard seabed provides the solid substrate needed to support sessile benthic communities, often forming 'hotspots' of biodiversity such as coral and sponge gardens. For the offshore resource and energy industry, knowledge of the distribution of hard versus soft seabed is important for planning infrastructure (pipelines, wells) and to managing risk posed by geo-hazards such as migrating sand waves or mass movements on steep banks. Maps that delineate areas of hard and soft seabed are therefore a key product to the informed management and use of Australia's vast marine estate. As part of the Australian Government's Offshore Energy Security Program (2007-2011) and continuing under the National CO2 Infrastructure Plan (2011-2015), Geoscience Australia has been developing integrated seabed mapping methods to better map and predict seabed hardness using acoustic data (multibeam sonar), integrated with information from biological and physical samples. The first method used was a two-stage, classification-based clustering method. This method uses acoustic backscatter angular response curves to derive a substrate type map. The angular response curve is the backscatter value as a function of the incidence angle, where this angle lies between the incident acoustic signal from the normal. The second method was a prediction-based classification, using a machine learning method called random forest. This method was based on bathymetry, backscatter data and their derivatives, as well as underwater video and sediment data. The techniques developed by Geoscience Australia offer a fast and inexpensive assessment of the seabed that can be used where intensive seabed sampling is not feasible. Moreover, these techniques can be applied to areas where only multibeam acoustic data are available. Importantly, the identification of seabed substrate types in spatially continuous maps provides valuable baseline information for effective marine conservation management and infrastructure development.

Vadose calcretisation commences with precipitation of micritic calcite from carbonate-rich meteoric water in the soil moisture zone. Through time, calcrete is subjected to repeated episodes of vadose cementation, dissolution, and brecciation of earlier-formed soil components, giving rise to stratigraphically complex soil profiles. The degree of complexity of individual profiles is largely influenced by the geomorphological setting and hydrological history of the local groundwater systems. Morphological similarities of calcrete duricrusts form the basis for establishing inventories of textural, compositional and physiographic features for Quaternary calcrete soil profiles and their evolutionary stages. Such inventories are useful tools for palaeo-environmental reconstruction, although calcrete duricrusts can be either an advantage or an obstacle for mineral exploration, depending on the level of understanding of calcrete and its relationship to the bedrock. Assessment of the timing of the main phases of carbonate precipitation indicates that calcrete soil profiles can attain maturity within a relatively short time. Problems with establishing a reliable time frame for differentiating Quaternary calcrete duricrusts from older counterparts represent a major challenge for further research.

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Meteorites are associated with five impact structures in Australia. Three of them are group IIIAB irons (Wolf Creek, Henbury, and Boxhole), Veevers is a group IIAB iron, and material recovered from the crater at Dalgaranga is a mesosiderite stony-iron. The impacts range in age from a few thousand years (Dalgaranga, Henbury, Veevers, and Boxhole) to 300,000 years (Wolfe Creek Crater). Metallographic studies of the surviving fragments at some of the craters show that impact damage ranges from simple fracturing, through shock-hardening of metal, to plastic and shear deformation, reheating and attendant recrystallisation, and, ultimately, melting. Details of the microstructures of surviving fragments of iron meteorite from the craters suggest that shear deformation may have been an important mechanism in the disruption of the projectiles. Frictional heating from viscous drag between projectile and target, and from rapid shear deformation within the projectile, may be sufficient to melt and vaporise significant portions of the projectiles and account for the large deficit of meteoritic material from Australian impact craters.