Legacy product - no abstract available

Two major geochemical datasets recently compiled are the National Geochemical Survey of Australia (NGSA) and the Radiometric Map of Australia. The geochemical survey of Australia measures floodplain sediments from 1186 catchments, covering ~80% of the country (average sample density 1 sample per 5500 km2). Samples were collected at two depths: 0-10 cm below the surface and between on average 60 and 80 cm depth. Samples were dried and sieved to either <2 mm (coarse) or <75 mm (fine) fractions, yielding four samples per site. The Radiometric Map has been generated by merging all available gamma-ray surveys into one seamless and levelled dataset with a consistent radioelement datum. The new map enables quantitative assessment of the distribution of potassium (%K), uranium (equivalent ppm U) and thorium (equivalent ppm Th) over about 80% of the Australian landmass. These datasets, together with geochemical assays of rock and regolith materials from the national OZCHEM databases, have been integrated and analysed at a national scales to better understand the distribution of K, Th and U. Surface concentration of these elements are associated with primary and secondary factors. Primary factors relate to the lithology and mineralogy of the parent material, whereas, secondary factors relate to low pressure and temperature hydrothermal alteration processes and weathering. To increase the utility of these data for mineral exploration we have calibrated the airborne radioelement grids using rock and sediment geochemistry to generate surface geochemical maps of K, Th and U in rocks and regolith materials. These datasets and thematic maps derived from modelling provide a broad framework in which to interpret more localised mineral systems. Systematic differences between the measured geochemistry and radioelement estimates derived from gamma-ray spectrometry provide new insights into the limitations of the gamma-ray spectrometric method for radioelement mapping.

The Australian Geological Survey Organisation (AGSO) flew an airborne geophysical survey of 45 459 line km covering the northern part of the Wangaratta 1:250 000 map Sheet area with an extension west onto the Shepparton 1:250 000 Sheet area. This survey formed part of the National Geoscience Mapping Accord and was jointly funded by AGSO and the Geological Survey of Victoria. The remainder of the Wangaratta 1:250 000 map Sheet area was flown under contract for the Geological Survey of Victoria. The AGSO flown survey, (Wangaratta North) was flown along east-west flight lines 200 metres apart at an altitude of 80 metres above ground level. The survey was flown from March to May 1997. The total magnetic intensity, gamma-ray spectrometric and digital elevation model data collected during the survey, have been processed and are available for purchase. These data are sold as digital point located data, grids and hardcopy maps, by the Australian Geological Survey Organisation. Colour and greyscale pixel image maps are also available.

The Australian Geological Survey Organisation (AGSO) flew an airborne geophysical survey of 69 086 line km covering the entire Cootamundra 1:250 000 map Sheet area in the Lachlan Fold Belt of New South Wales. The survey formed part of the National Geoscience Mapping Accord and was jointly funded by AGSO, Department of Primary Industries and Energy and the Geological Survey, New South Wales Department of Mineral Resources. The survey was flown along east-west flight lines, 250 metres apart at an altitude of 80 metres above ground level. AGSO flew the survey over two periods; from November to December 1997 and from February to March 1998. The total magnetic intensity, gamma-ray spectrometric and digital elevation model data collected during the survey, have been processed and are available for purchase. These data are sold as digital point located data, grids and hardcopy maps, by the Australian Geological Survey Organisation. Colour and greyscale pixel image maps are also available.

No abstract available

No abstract available

Paper presented at the August 2001 ASEG Conference.

The Radiometric 3D Atlas is a series of interactive X3D Models that can be viewed in your web browser. The Atlas consists of an overall model of Australia and eight detailed regional models from each state and territory. Each model includes; images from the Radiometric, Magnetic Anomaly and Gravity Anomaly data sets; a digital elevation model; coastline, cities/towns, state borders, mines; and 1:250 000 topographic map index. Software required Geoscience Australia's X3D and older VRML models require the free plugin BS Contact and work best with the web browser Internet Explorer version 6 or higher. More information about the plugin is available from the <a href=http://www.ga.gov.au/resources/multimedia/about-3dmodels.jsp>About 3D Modelling and Required Software</a> page. Size Approximately 163 MB for all the models. Startup download is 8.52 MB - the remaining datasets download when selected.

100 counts/sec

No abstract available