Mapping the Australian Tectonic Plate Thickness

Sustainable development and transition to cleaner energy sources is placing ever-increasing demand on global supplies of base metals (copper, zinc, lead and nickel) and co-produced critical minerals (e.g. cobalt, germanium). For Australia to maintain global leadership in the supply of base metals, it is essential to focus exploration on prospective, yet previously unexplored or underexplored, frontier regions. The EFTF program has addressed ways of better predicting where such prospective frontiers and mineral deposits might be found, recognising that they may be several hundred metres below the surface.

It is estimated that around 80 per cent of Australia's subsurface is largely under-explored; this is particularly the case in Northern Australia. Given that lead times from discovery to mining can exceed 20 years, there is a need to accelerate discovery rates to provide a longer-term pipeline of mineable resources.

This EFTF project aimed not only to identify areas that are prospective for finding mineral resources, but also areas that are unfavourable for sediment-hosted base metal mineral exploration. Together with the Australian National University and Harvard and Columbia Universities, Geoscience Australia discovered that 85 per cent of global sediment-hosted base metal deposits, including all giant deposits, are located above areas where tectonic plates are 170 km thick.

To facilitate more effective exploration in these buried landscapes Geoscience Australia is developing databases, methodologies and predictive models to better understand the nature of the cover. We aim to generate 3-dimensional surfaces of the depths to major chronostratigraphic interfaces including the bases of Cenozoic, Mesozoic, Palaeozoic and Proterozoic packages.

The most significant outcome of this project has been increased interest by the mining sector in exploring the prospective frontier regions identified in this work, with increased tenement uptake in some of these regions. The results of plate thickness mapping undertaken with EFTF funding has contributed to this increase in interest.

There has been significant media and industry interest in this work, with some companies reported to be interested in establishing a consortium in Australia on the back of this breakthrough. Any increased industry investment will help maintain Australia’s world leading mining, equipment, technology and services (METS) sector.

Projects like this were a contributing factor in a major multinational mining company’s (Anglo American) decision to return to mineral exploration in Australia. The company has cited pre-competitive geoscience datasets and knowledge generated by Geoscience Australia and the Geological Survey of Queensland through the EFTF program as being important factors in their investment decision. The tenements taken up by this company are generating $546,000 per annum in rent payments to the Queensland Government.

For more information on the outcome from this study, you can find them in our return on investment report.