Government Geological Surveys study the Earth at the regional, province or national scale, and acquire vast volumes of technically complex data. These data must be high quality, fit for purpose, durable, and readily accessible and usable by industry. Increasingly, users require the geological information contained within the data as well as the data itself. High performance computers facilitate a step-change in advanced processing and modelling of large, complex data, and will help Government deliver more sophisticated products to industry and researchers. Data enhancement and manipulation are no-longer limited by the computational effort required, and there are no artificial limits to the size of the data or model, or the data resolution that can be processed. Geoscience Australia is collaborating with the National Computational Infrastructure facility (NCI) at the Australian National University to develop advanced methods for extracting the maximum geological information from large data volumes. The new methods include: Modelling of potential field data in spherical coordinates to create continental-scale reference models of density and magnetic susceptibility; Inversion of magnetotelluric tensor data to a full 3D mesh of resistivities, and; Monte Carlo inversion of AEM responses to assess the reliability and sensitivity of conductivity-depth images. These algorithms are being implemented in a new Virtual Geophysical Laboratory where government data and advanced processing methods are brought together in a single high performance computer environment.

In the literature of remote sensing image analysis, an endmember is defined as a pixel containing only one land cover substance. However, with the varying resolutions of available sensors, in most cases a single pixel in a satellite image contains more than one type of land cover substance. One challenge is to decompose a pixel with mixed spectral readings into a set of endmembers, and estimate the corresponding abundance fractions. The linear spectral unmixing model assumes that spectral reading of a single pixel is a linear combination of spectral readings from a set of endmembers. Most linear spectral unmixing algorithms rely on spectral signatures from endmembers in pre-defined libraries obtained from previous on-ground studies. Therefore, the applications of these algorithms are restricted to images whose extent and acquisition time coincide with those of the endmember library. We propose a linear spectral unmixing algorithm which is able to identify a set of endmembers from the actual image of the studied area. Existing spectral libraries are used as training sets to infer a model which determines the class labels of the derived image based endmembers. The advantage of such approach is that it is capable of performing consistent spectral unmixing in areas with no established endmember libraries. Testing has been conducted on a Landsat7 ETM+ image subset of the Gwydir region acquired on Jun 22, 2008. Three types of land cover classes: bare soil, green vegetation and non-photosynthetic are specified for this test. A set consisting of 150 endmember samples and a number of ground abundance observations were obtained from a corresponding field trip. The study successfully identified an endmember set from the image for the specified land cover classes. For most test points, the spectral unmixing and estimation of the corresponding abundance are consistent with the ground validation data.

The National Dynamic Land Cover Dataset (DLCD) classifies Australian land cover into 34 categories, which conform to 2007 International Standards Organisation (ISO) Land Cover Standard (19144-2). The DLCD has been developed by Geoscience Australia and the Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES), aiming to provide nationally consistent land cover information to federal and state governments and general public. This paper describes the modeling procedure to generate the DLCD, including machine learning methodologies and time series analysis techniques involved in the process.

New geological and geophysical data in the North Queensland region provides new insights into the geology and geodynamics of the region. One major finding from studies in North Queensland is the recognition of the eastern boundary of the Mount Isa province as a west-dipping structure within the crust. This separates the Mount Isa Province (in the west) from the Numil and Kowanyama Seismic Provinces (in the east). IOCG deposits in the North Queensland region are situated west, in the hangingwall, of the boundary with the boundary at some depth beneath them. This is an analogous location to the Olympic Dam deposit in South Australia. Potential field data allow tracking of the boundary to the north and to the south, providing insights into IOCG exploration potential in North Queensland. Advanced inversion techniques, such as mineral estimation from potential field inversion results, also allow targetting of these IOCG deposits to the south and to the north of known deposits.

Uranium exploration expenditure in Australia has increased progressively since 2003 mainly because of the significant increases in spot market uranium prices in recent years. In 2007-08, uranium exploration expenditure increased to a record level of $231.6 million , which is approximately double the 2006-07 expenditure ($111.4 million). The majority of expenditure was in South Australia (51%), followed by the Northern Territory (21%), Queensland (16%) and Western Australia (12%). Uranium exploration expenditure in the 2008 September quarter ($56.7 million) was above the 2007 September quarter ($50 million). However the difference is the expenditure trend from the June quarter to the September quarter, in 2007 expenditure grew by $6.7 million whereas in 2008 expenditure reduced by $6.0 million. This reduction may reflect that the current global economic crisis is affecting the level of uranium exploration spending. Geoscience Australia prepares annual estimates of Australia's uranium resources within categories used for international reporting by the Uranium Group (a joint initiative of the OECD Nuclear Energy Agency and the International Atomic Energy Agency). The estimates are for resources of recoverable uranium after losses due to mining and milling have been deducted. As of December 2008, Australia's Reasonably Assured Resources (RAR) recoverable at costs of <US$80/kg U were estimated to be 1,111,000 t U. This represents an increase of 12% over the estimates for the previous year, mainly due to large increase in both reserves and resource estimates for Olympic Dam deposit (South Australia) and transfer of resources from Inferred in RAR. This means Australia's share of the world's total RAR of uranium recoverable at <US$80/kg U has increased to about 37% . <truncated>

In early 2008 Geoscience Australia and Mineral Resources Tasmania acquired 141,234 km of high resolution (800m line spacing) aeromagnetic data over Bass Strait and the offshore marginal basins of western Tasmania. The data fill a gap in the existing aeromagnetic coverage between Tasmania and mainland Australia and provide fresh insights into basement structure and its control on basin architecture and sedimentation patterns during Gondwanan continental break-up and the separation of Australia from Antarctica. Prominent in the new data are several northwest-trending basement faults that extend from the mainland into westernmost Tasmania and the South Tasman Rise; they appear to represent an offshore extension of previously mapped structures in western Victoria (Hummocks and Yarramyljup Faults). These structures postdate, truncate and offset in a sinistral sense many older north- and northeast-trending basement structures, including the late Neoproterozoic Arthur lineament in Tasmania, the Bambra fault in central Victoria and the boundary between the Lachlan and Delamerian Orogens (Moyston Thrust) in western Victoria. The Hummocks Fault coincides with a narrow belt of ultramafic rocks and possibly continues offshore as a series of prominent magnetic anomalies whereas the Yarramyljup Fault may form the western limit of Proterozoic (Tyennan) basement in Tasmania. The distribution and geometry of Mesozoic-Tertiary offshore sedimentary basins in western Tasmania and the South Tasman Rise is consistent with reactivation of the older basement structures in a north-south-directed transtensional tectonic regime. Magmatic rocks intruded into the Bass, Otway and Sorell Basins and Torquay Sub-Basin are clearly delineated in the new aeromagnetic data.

National Exposure Information System - Program for Brisbane 21-22 October 2010 Agenda

NEXIS Queensland Stakeholder Engagement Workshops Minutes Policy makers, researchers and asset managers attended the Queensland stakeholder engagement workshops to better understand the National Exposure Information System (NEXIS) and the benefits it currently provides. The workshop also provided the opportunity for participants to contribute towards the advancement of NEXIS by guiding the alignment of its development strategies to better meet their future needs.

The National Exposure Information System (NEXIS) is a major capability being developed by Geoscience Australia. NEXIS provides nationally consistent exposure information to support risk assessments of buildings, people and infrastructure to various hazards. Three key components are central to an understanding of risk; the hazard, what is exposed and how vulnerable the exposed elements are. NEXIS provides the exposure component.

No abstract available