Legacy product - no abstract available

Extended abstract version of the abstract (Geocat#73747) submitted in March 2012 and accepted for an oral presentation at the symposium.

The individual surveys that comprise Australia's national airborne gamma-ray spectrometric radioelement database are not all registered to the same datum. Older survey results are presented in units of counts/sec, which depend on factors such as survey flying height and detector volume. Even recent surveys can have a significant mismatch along common borders due to limitations in spectrometer calibration and data processing procedures, as well as environmental effects that result in temporal changes in the gamma-radiation fluence rate at the earth's surface. These problems limit the usefulness of the national radioelement database for uranium exploration, and other applications, as it is difficult to compare radiometric signatures observed in different parts of the continent. Geoscience Australia has recently undertaken an Australia-Wide Airborne Geophysical Survey (AWAGS), funded under the Australian Government's Onshore Energy Security Program, to serve as a radioelement baseline for all current and future airborne gamma-ray spectrometric surveys in Australia. The survey data were acquired and processed according to international standards, and the final estimates of radioelement concentrations along the AWAGS lines are consistent with the International Atomic Energy Agency's (IAEA) radioelement datum. The AWAGS survey has been used to adjust the hundreds of surveys that comprise the national radioelement database to a common datum. This was achieved by estimating, for each survey in the national database, correction factors that, once applied, minimize both the differences in radioelement estimates between surveys (where these surveys overlap) and the differences between the surveys and the AWAGS traverses. This effectively levels the surveys to the IAEA datum to produce a consistent and coherent national gamma-ray spectrometric coverage of the continent. The levelled database has been used to produce the first "Radiometric Map of Australia" - levelled and merged composite potassium (% K), uranium (ppm eU) and thorium (ppm eTh) grids over Australia at 100 m resolution. Interpreters can now reliably relate geochemical patterns observed in one area to similar patterns observed elsewhere, and better appreciate the significance of broad-scale variations in radioelement concentrations. There are several applications that will benefit from the updated database. These include uranium and thorium exploration through the ability to make quantitative comparisons between radiometric signatures in different survey areas, and the derivation of a radiation risk map of Australia for natural sources of radiation.

Legacy product - no abstract available

Spatial interpolation methods for generating spatially continuous data from point locations of environmental variables are essential for ecosystem management and biodiversity conservation. They can be classified into three groups (Li and Heap 2008): 1) non-geostatistical methods (e.g., inverse distance weighting), 2) geostatistical methods (e.g., ordinary kriging: OK) and 3) combined methods (e.g. regression kriging). Machine learning methods, like random forest (RF) and support vector machine (SVM), have shown their robustness in data mining fields. However, they have not been applied to the spatial prediction of environmental variables (Li and Heap 2008). Given that none of the existing spatial interpolation methods is superior to the others, several questions remain, namely: 1) could machine learning methods be applied to the spatial prediction of environmental variables; 2) how reliable are their predictions; 3) could the combination of these methods with the existing interpolation methods improve the predictions; and 4) what contributes to their accuracy? To address these questions, we conducted a simulation experiment to compare the predictions of several methods for mud content on the southwest Australian marine margin. In this study, we discuss results derived from this experiment, visually examine the spatial predictions, and compare the results with the findings in previous publications. The outcomes of this study have both practical and theoretical importance and can be applied to the spatial prediction of a range of environmental variables for informed decision making in environmental management. This study reveals a new direction in and provides alternative methods for spatial interpolation in environmental sciences.

The Tennant Creek Region OZCHEM database subset is comprised of 1662 wholerock analyses derived from AGSO field work and the literature. AGSO's complete OZCHEM database contains approximately 50000 analyses, mainly from Australia but some are also from Papua New Guinea, Antarctica, Solomon Islands and New Zealand. Approximately 32000 analyses of Australian rocks of all ages and some New Zealand Tertiary volcanics are available for sale. The location is stored with each analysis along with geological descriptions, including the host stratigraphic unit and lithology. Most samples have been collected by AGSO field parties.OZCHEM is stored in an ORACLE relational database and is available in Oracle export, comma-delimited relational ASCII, and Microsoft Access formats.

Package comprises a digital compilation of regional mapping of Bathurst (SI5508) 1:250 000 map by AGSO and NSW Department of Mineral Resources, under NGMA from 1991 to 1996.

This record describes digital data compilation product, where several individual items are grouped for delivery on single CD-ROM. Content and number of items included in the compilation package can vary, depending on size of the individual items. The contents of this CD-ROM are as follows: Catalog # Title 34192 OZMIN national mineral deposits dataset with documentation 33468 OZMIN national mineral deposits documentation Record 2000/18 34735 Mineral Occurrence Location Database (MINLOC), digital package including documentation

Map showing the Geomorphic Features of the Australian Margin and Island Territories. The features were interpreted from Geoscience Australia's 250 m horizontal bathymetry model and other published data, and include those specified in the International Hydrographic Office definitions.

Package comprises a digital compilation of regional mapping of Bathurst (SI5508) 1:250 000 map by AGSO and NSW Department of Mineral Resources, under NGMA from 1991 to 1996.