Minerals Alert February 2009

A monthly online newsletter with product news, data releases and projects related to the minerals and energy exploration industry.

  1. The Radiometric Map of Australia
  2. New gravity survey data added to the Australian National Gravity Database
  3. Gawler Craton half a billion years older than previously thought
  4. Redevelopment of Geoscience Australia website
  5. Update on geophysical data releases
  6. About Minerals Alert

1. The Radiometric Map of Australia

The new Radiometric Map of Australia will be available from the Geoscience Australia sales centre and website from Monday, 23 February 2009. The map is a ternary, coloured composite map of the potassium (K=red), uranium (U=blue) and thorium (Th=green) radioelement concentrations across Australia and northern Tasmania at 1:5 million scale. It was compiled, in collaboration with the States and the Northern Territory by combining more than 450 individual airborne gamma-ray spectrometric surveys into a single seamless compilation. The surveys were levelled to a common baseline which was derived from the Australia Wide Geophysical Survey (AWAGS) flown by Geoscience Australia in 2007. AWAGS surveys were funded by the Australian Government's Onshore Energy Security Program (OESP) and covered the entire Australian Continent and Tasmania with north-south flight-lines space 75 km apart, and east-west tie-lines spaced 400 km apart. AWAGS was calibrated to international standards and provides a radiometric datum which allows comparison and merging of surveys from different parts of Australia. The map will be available from the Geoscience Australia Sales Centre and website on 23 February 2009.

The gridded digital data which underpins the map will be released at the same time. These data will be available free of charge for download via the internet using the Geophysical Archive Data Delivery System (GADDS). The basic grids are potassium, uranium, thorium and terrestrial dose rate (total count) grids at 100 metre cell size. These will be available in both filtered and unfiltered versions. Grids of the ratios between radioelements (Th/K, U/K, U/Th) and total dose (terrestrial dose rate plus dose due to cosmic radiation) derived from the filtered grids also will be available.

Because the grids are large (approximately 5.5 GB each), users planning to access entire grids at full resolution should contact Murray Richardson to arrange alternative means of acquiring the digital data.

For further information, email murray.richardson@ga.gov.au; or phone +61 2 6249 9229.

2. New gravity survey data added to the Australian National Gravity Database

Since November 2008, 37 277 new gravity stations have been added to the Australian National Gravity Database.

These new data comprise 7 465 stations from open file company surveys in Queensland, approximately 25 000 stations from South Australia and 4 812 stations from the Northern Territory.

The South Australian data are infill stations formerly embargoed until December 2008. Infill data had been collected during the 2007 Northern Olympic Domain Gravity Survey by Primary Industries and Resources SA (PIRSA) in a joint venture with exploration companies.

Queensland open file gravity data are on the 1:1 million sheet areas for Normanton, Cloncurry, Clermont and Rockhampton. The infill data from the Northern Olympic Domain Gravity Survey are situated on the Oodnadatta, Tarcoola and Broken Hill sheet areas.

The 4 812 stations from the Northern Territory consist of 4 609 infill stations (previously embargoed) and 203 open file company data. The infill data are from the Northern Territory 2008 Central Arunta Gravity Survey and are on the Alice Springs 1:1 million sheet area. These data were from a joint venture between the Northern Territory Geological Survey and exploration companies as part of the Northern Territory Government's 'Bringing Forward Discovery' initiative. Adjoining, and logically part of the Central Arunta Survey are the 203 open file company stations. Grids for the Central Arunta Gravity Survey now incorporate the extra infill data. The main Central Arunta Gravity Survey dataset (11 829 stations) were released in November 2008.

All data have been supplied to Geoscience Australia by the respective State or Territory Geological Survey.

Open file data in the Australian National Gravity Database can be obtained free-of-charge via the internet using the Geophysical Archive Data Delivery System (GADDS).

For further information, email mario.bacchin@ga.gov.au or phone +61 2 6249 9308.

3. Gawler Craton half a billion years older than previously thought

Scientists from Geoscience Australia have identified Mesoarchean rocks from South Australia's Eyre Peninsula which are more than three billion years old. Rocks of this age are uncommon, difficult to find and previously were thought to be restricted to areas of the Pilbara and Yilgarn Craton regions of Western Australia. The new age data indicate that this rock is approximately twice as old as first thought, and forms basement to the iron-rich sediments of the Middleback Ranges, which have been mined for iron ore since the late 1880s.

For further information, visit the December 2008 issue of AusGeo News.

4. Redevelopment of Geoscience Australia Website

Minerals Alert has been relocated on the Geoscience Australia website in the first stage of a web redevelopment project. From February 2009 the latest Minerals Alert and the archive can be accessed from News and Media.

5. Update on geophysical data releases

Data from Cooper Basin East and Cooper Basin West airborne magnetic and radiometric surveys are due for release on 10 February 2009.

Requests for quotation for gravity and airborne magnetic and radiometric survey in Cape York closed on 20 January 2009.

The current status of Geoscience Australia's geophysical survey data acquisition is available in a comprehensive table from the Geoscience Australia website.

For further information, email murray.richardson@ga.gov.au; or phone +61 2 6249 9229.

6. About Minerals Alert

For more information contact Mike Huleatt on +61 2 6249 9087 or email mike.huleatt@ga.gov.au.

To view past editions of Geoscience Australia's Minerals Alert, visit the Minerals Alert Newsletter Archive.

Topic contact: media@ga.gov.au Last updated: October 4, 2013