2010
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The gravitational attraction of the Galactic centre leads to the centrifugial acceleration of the Solar system barycentre. It results in secular aberration drift which displaces the position of the distant radio sources. The effect should be accounted for in high-precision astrometric reductions as well as by the corresponding update of the ICRS definition.
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The Australian Government policy is to ensure that uranium mining, milling and rehabilitation is based on world best practice standards. A best practice guide for in situ recovery (ISR) uranium mining has been developed to communicate the Australian Government's expectations with a view to achieving greater certainty that ISR mining projects meet Australian Government policy and consistency in the assessment of ISR mine proposals within multiple government regulatory processes. The guide focuses on the main perceived risks; impacts on groundwaters, disposal of mining residues, and radiation protection. World best practice does not amount to a universal template for ISR mining because the characteristics of individual ore bodies determine the best practice
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Assessment of existing volcanic ash hazard models for South East Asia: towards development of an open-source, volcanic ash impact computational model for Indonesia
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North Queensland Geodynamic and Mineral System Synthesis
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Total contribution of six recently discovered submerged coral reefs in northern Australia to Holocene neritic CaCO3, CO2, and C is assessed to address a gap in global budgets. CaCO3 production for the reef framework and inter-reefal deposits is 0.26-0.28 Mt which yields 2.36-2.72 x105 mol yr-1 over the mid- to late-Holocene (<10.5 kyr BP); the period in which the reefs have been active. Holocene CO2 and C production is 0.14-0.16 Mt and 0.06-0.07 Mt, yielding 3.23-3.71 and 5.32-6.12 x105 mol yr-1, respectively. Coral and coralline algae are the dominant sources of Holocene CaCO3 although foraminifers and molluscs are the dominant constituents of inter-reefal deposits. The total amount of Holocene neritic CaCO3 produced by the six submerged coral reefs is several orders of magnitude smaller than that calculated using accepted CaCO3 production values because of very low production, a 'give-up' growth history, and presumed significant dissolution and exports. Total global contribution of submerged reefs to Holocene neritic CaCO3 is estimated to be 0.26-0.62 Gt or 2.55-6.17 x108 mol yr-1, which yields 0.15-0.37 Gt CO2 (3.48-8.42 x108 mol yr-1) and 0.07-0.17 Gt C (5.74-13.99 x108 mol yr-1). Contributions from submerged coral reefs in Australia are estimated to be 0.05 Gt CaCO3 (0.48 x108 mol yr-1), 0.03 Gt CO2 (0.65 x108 mol yr-1), and 0.01 Gt C (1.08 x108 mol yr-1) for an emergent reef area of 47.9 x103 km2. The dilemma remains that the global area and CaCO3 mass of submerged coral reefs are currently unknown. It is inevitable that many more submerged coral reefs will be found. Our findings imply that submerged coral reefs are a small but fundamental source of Holocene neritic CaCO3, CO2, and C that is poorly-quantified for global budgets.
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Seismic interval velocities derived from stacking velocities can provide some clues to determination of rock lithology. This concept has been applied to understand the divergent dipping reflector (DDR) and seaward dipping reflector (SDR) packages over the Wallaby Plateau and Wallaby Saddle that were imaged on the 2008/2009 seismic survey GA310 contracted by Geoscience Australia. Root mean square velocities (Vrms) used to calculate interval velocities (Vint) were derived from long cable data. Vrms were picked on traces after pre-stack time migration, and the 4th order normal move-out (NMO) correction was implemented. Therefore, distortions to interval velocities due to insufficient curvature of NMO curve at short offsets, structural dip and ray bending due to stratification are assumed to be largely suppressed. Consequently Vrms velocities are assumed to approximate average velocities.
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The 1:2.5M scale geology of Australia data documents the distribution and age of major stratigraphic, intrusive and medium to high-grade metamorphic rock units of onshore Australia. This edition contains the same geological content as the previous edition, but is structured according to Geoscience Australia's 2010 data standards and is provided in additional digital formats. The dataset was compiled to use at scales between 1:2.5 million and 1:5 million inclusive. The units distinguished/mapped mainly represent stratigraphic supergroups, regional intrusive associations and regional metamorphic complexes. Groupings of Precambrian units in the time-space diagram are generally separated by major time breaks; Phanerozoic units are grouped according to stratigraphic age i.e. System/Period. The time-space diagram has the added benefit that it provides a summary of units currently included on the themes. The method used to distinguish sedimentary and many volcanic units varies for each geological eon as follows: <ul><li>Cainozoic units are morphological units which emphasise the relationship of the sedimentary fill to the landscape.</li> <li>Mesozoic units are regionally extensive to continent-wide time-rock units which emphasise the System of Period(s).</li> <li>Palaeozoic units are stratotectonic units that emphasise either the dominant System or Period(s) or the range of Periods.</li> <li>Proterozoic units are commonly regional stratotectonic units - separated by major time breaks and split into the Palaeoproterozoic, Mesoproterozoic and Neoproterozoic Eras - which are generally unique to each cratonic region.</li> <li>Archaean units are regional lithological units grouped into broad time divisions.</li> <li>Metamorphic units are lithological units which emphasise the metamorphic facies and timing of the last major metamorphic event. </li> <li>Igneous units are regional units which emphasise the dominant lithology and are grouped into broad time divisions.</li></ul>
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Understanding marine biodiversity has received much attention from an ecological and conservation management perspectives. The Australian Government's Department of the Environment, Water, Heritage and the Arts has initiated the Commonwealth Environment Research Facilities (CERF) initiative to enhance the understanding of Australia's natural environment for policy making. One part of the CERF initiative through the marine biodiversity hub was to predict biodivesity from expansive physical variables. This talk presents some of the work arising from this area.
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Crust predating 3.0 Ga within the Australian continent has previously been identified only in relatively restricted areas of the Yilgarn and Pilbara Cratons of Western Australia. Here we report the discovery of early Mesoarchean (~3150 Ma) rocks in the eastern Gawler Craton of South Australia. Rocks of broadly Mesoarchean age have been inferred by some authors to exist at depth beneath the Gawler Craton (Creaser and Fanning, 1993; Daly and Fanning, 1993), but no rocks of this age have been identified previously at the surface. The newly identified Mesoarchean granites and gneisses crop out across at least ~20 x 30 km and, on the basis of inherited zircon and Nd-isotopic compositions, are inferred to be present at depth beneath a region of at least ~1500 km2.