2009
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Surprisingly few natural hydrocarbon seeps have been identified in Australia's offshore basins despite studies spanning thirty years. Initial studies of natural hydrocarbon seepage around the Australian margin were generally based around the geochemical analysis of stranded bitumens, water column geochemical `sniffer' sampling, synthetic aperture radar or airborne laser fluorsensor. Later studies involved the integration of these remote sensing and geochemical techniques with mutli-channel and shallow seismic. A review of these earlier studies indicates that many seepage interpretations need to be re-evaluated and that previous data sets, when set in a global context, often represent normal background hydrocarbon levels. Relatively few sites of proven natural hydrocarbon seepage in Australia's offshore sedimentary basins can be reconciled with the dominantly passive margin setting and low recent sedimentation rates, which are not favourable for high rates of seepage, and difficulties in proving seepage on high energy, shallow carbonate shelves, where seabed features may be rapidly reworked and modern marine signatures are overprinted on authigenic seep carbonates. Active thermogenic methane seepage on the Yampi Shelf, the only proven documented occurrence in Australia, is driven by deposition of a thick Late Tertiary carbonate succession and Late Miocene tectonic reactivation. Therefore, to increase the success of detecting and correctly interpreting natural hydrocarbon seepage, data need to be analysed and integrated within the context of the local geological setting, and with an understanding of what is observed globally.
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Map produced for the Australian Government Solicitor in July 2009 showing the Torres Strait Regional Claim. Produced for the use of AGS in the their provision of advice regarding native title.
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Geoscience Australia undertakes classification of biophysical datasets to create seabed habitat maps (termed 'seascapes') for the Australian margin and adjacent sea floor. Seascapes describe a layer of ecologically meaningful biophysical properties that spatially represents potential seabed habitats. Each seascape area corresponds to a region of the seabed that contains similar biophysical properties and, by association, potential habitats and communities. The lack of available standardised biological data at the national scale precludes the integration of biological information into the derivation of national seascapes. By focusing on a much smaller scale over tens of kilometres near the Glomar Shoals in Western Australia, referred to as 'local scale', available biological data were integrated into new derivations of seascapes and results compared with seascapes without these data. Using physical data as described in Whiteway et al. 2007 (GA Record 2007/11) and demersal fish data obtained from the 1967 Russian Berg-3 survey, we have derived four new local sets of seascape to compare the effects of integrating biological data: 1) Standard seascapes using only physical data, 2) Seascapes with an additional biology layer based on the Shannon diversity index, 3) Seascapes with an additional biology layer based on the Simpson diversity index, and 4) Seascapes with an additional layer of randomly-generated data. At the 'regional-scale' we derived two sets of seascapes: 1) Seascapes with an additional biology layer based on the Shannon diversity index that encompasses the entire Berg-3 survey area in northwest Australia, and 2) Standard seascapes using only physical data for the same area. This datsets is the local scale Glomar Shoals seascape produced with a biological layer called the 'Shannon Diversity Index'.
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A review of Australia's Energy sector and development in the year 2009.
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This map shows the boundary of the Maratime Security Zones for each port for the purpose of the Maratime Transport Office Security Act 2003. 4 sheets (colour) October 2009 Not for sale or public distribution. Contact Manager LOSAMBA project.
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Geoscience Australia undertakes classification of biophysical datasets to create seabed habitat maps (termed 'seascapes') for the Australian margin and adjacent sea floor. Seascapes describe a layer of ecologically meaningful biophysical properties that spatially represents potential seabed habitats. Each seascape area corresponds to a region of the seabed that contains similar biophysical properties and, by association, potential habitats and communities. The lack of available standardised biological data at the national scale precludes the integration of biological information into the derivation of national seascapes. By focusing on a much smaller scale over tens of kilometres near the Glomar Shoals in Western Australia, referred to as 'local scale', available biological data were integrated into new derivations of seascapes and results compared with seascapes without these data. Using physical data as described in Whiteway et al. 2007 (GA Record 2007/11) and demersal fish data obtained from the 1967 Russian Berg-3 survey, we have derived four new local sets of seascape to compare the effects of integrating biological data: 1) Standard seascapes using only physical data, 2) Seascapes with an additional biology layer based on the Shannon diversity index, 3) Seascapes with an additional biology layer based on the Simpson diversity index, and 4) Seascapes with an additional layer of randomly-generated data. At the 'regional-scale' we derived two sets of seascapes: 1) Seascapes with an additional biology layer based on the Shannon diversity index that encompasses the entire Berg-3 survey area in northwest Australia, and 2) Standard seascapes using only physical data for the same area. This datsets is the local scale Glomar Shoals seascape produced without a randomly generated biological layer.
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Beginning in the Archean, the continent of Australia evolved to its present configuration through the accretion and assembly of several smaller continental blocks and terranes at its edges. Australia grew usually by convergent plate margin processes, such as arc-continent collision, continent-continent collision or through accretionary processes at subduction zones. The accretion of several island arcs to the Australian continent, through arc-continent collisions, played an important role in this process, and the geodynamic implications of some Archean and Proterozoic island arcs recognised in Australia will be discussed here.
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ABSTRACT: Building on method developments achieved during a series of precursor pilot projects, the National Geochemical Survey of Australia (NGSA) project targets catchment outlet (overbank) sediments as a uniform sampling medium. These transported, fine-grained materials are collected (from a shallow and a deeper level) near the lowest point of 1390 catchments, which cover 91% of the country. Dry and moist Munsell® colour, soil pH and electrical conductivity and pH of 1:5 (soil:water) slurries are recorded and laser particle size analysis and infrared spectroscopy are performed. The dried samples are sieved into two grain-size fractions (<2 mm and <75 mm) that are analysed by x-ray fluorescence (XRF) and inductively-coupled mass spectrometry (ICP-MS) (multi-element, total analyses), by ICP-MS after aqua regia digestion (multi-element, including low level gold), and specialised methods for platinum group elements, fluorine and selenium. At the time of writing, 78% of the samples have been collected and most analyses are completed for the first 25% of samples. The project is due for completion in June 2011.
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This map shows the boundary of the Maritime Security Zones for each port for the purpose of the Maritime Transport Office Security Act 2003. 5 Sheets (Colour) December 2009 Not for sale or public distribution Contact Manager LOSAMBA project.
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This map shows the boundaries of the security regulated port for the purpose of the Maritime Transport & Office Security Act 2003. 5 Sheets (Colour) December 2009 Not for sale or public distribution Contact Manager LOSAMBA project, PMD