Map showing Victoria’s geological provinces and sampling points (blue dots) where recent petrophysical data has been collected. Data will be used to develop a picture of structural, mineralogical and thermal anomalies across the state, and is now available on the AuScope Portal.

The future of Australia’s mineral exploration success lies in successfully exploring under the 80% of the continent that is covered by regolith, or sediments. AuScope’s Subsurface Observation (formerly AGOS) team and partners have just added a new data piece to the puzzle.

With the help of Dr Robert Woodcock and his team at CSIRO, AuScope’s Subsurface Observation team, led by Dr. David Belton at the University of Melbourne, have been able to optimise recently-updated software for delivering charted petrophysical data onto the AuScope Portal, in order to provide ready access to this data for members of the geoscience community.

The team have completed uploading borehole petrophysics results for 4500 metres of diamond core representing 50 sites, the bulk of which sample subsurface geology in Victoria. These boreholes aimed to investigate structural, mineralogical and thermal anomalies.

A total of 27 holes delivered extensive meterage (average 160 metres per hole) in basement lithologies and provide a comprehensive picture of the subsurface physical properties including density, p-wave velocity, resistivity, magnetic susceptibility as well as natural gamma output.  A further 22 sites were sampled for strategically important lithologies of interest in geothermal studies. Many of these sites also underwent comprehensive thermal conductivity analyses.

Petrophysical-Log-Example

Example of graphed petrophysical data that is now available on the AuScope Portal. Viewing data in this way allows geologists to determine areas of interest downhole, based on anomalies between datasets. For example, a spike in magnetic susceptibility, ‘Mag. sus.’ and ‘Resistivity’ may indicate the presence of metallic mineralogy, which may spark further investigation to determine whether it is possibly ore-bearing.

This component milestone culminates a number of different projects with CSIRO, Geoscience Australia and the Geological Survey of Victoria, whose various aims include:

  • Developing new drilling techniques, such as sonic drilling
  • Expanding the amount and type of datasets, from lithogeochemical to extended petrophysical data, for improved mineral exploration vectoring
  • Verifying surface and downhole geophysical data collection technologies, which vastly improves modelling of geophysical data
  • Geothermal exploration

To view graphical petrophysical data, please visit the AuScope Portal. To access raw petrophysical and seismic data, please get in touch with project leader Dr. David Belton at dxbelton@unimelb.edu.au.

 


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