New airborne electromagnetic data reduces mineral exploration risk
20 February 2015
The recent release of the southern Thomson Orogen VTEMplus® airborne electromagnetic (AEM) survey dataset will provide better context for understanding the mineral potential of this relatively data-poor region of central and eastern Australia.
The Thomson Orogen is a large geologically complex area that crosses New South Wales, South Australia, Northern Territory and Queensland. The exposed regions of the orogen host known mineral resources, but much of the orogen is covered by younger sedimentary basins, with some up to several kilometres thick. The new AEM survey data provides further insights into the region's geology and will enable better confidence to interpret and map the thickness of the sedimentary cover.
The southern Thomson Orogen project forms part of the broader UNCOVER Initiative, which has been developed under the auspices of the Australian Academy of Science, and which is a key element of the National Mineral Exploration Strategy. The strategy aims to address the challenges of 'greenfield' exploration in under-cover areas in Australia. An important method of exploring under cover is the ability to use pre-competitive data to map and characterise Australia's sedimentary cover and underlying mineralisation footprints.
The new data will give explorers fresh insights into the region's mineral potential, reducing risk and thereby encouraging exploration investment in this underexplored or 'greenfield' province. This will provide the minerals industry and groundwater resource managers with more confidence in further investigations of the complex geology of the southern Thomson Orogen and the overlying sedimentary basins.
Data collected during this project include a regional AEM survey with east-west flight lines over the Eulo Ridge, a mostly-buried basement feature. Two AEM traverse lines were flown from Tilpa to Eulo and Brewarrina to Thargomindah, in conjunction with complementary ground gravity and magnetotelluric (MT) data acquisition to map the major crustal boundary between the Lachlan and Thomson orogens. Additional MT and gravity data were also obtained along smaller, targeted traverses in Queensland for more detailed mapping of basement features on the Eulo Ridge.
Survey data were combined with available drill hole lithology or stratigraphy data, groundwater chemistry data, regional geophysical data (magnetics, gravity, radiometrics) and interpretations of the basement geology from existing geological and geophysical datasets.
The AEM survey was flown as part of research collaboration between Geoscience Australia, the Geological Survey of NSW and the Geological Survey of Queensland using the Geotech VTEMplus® helicopter-borne AEM system. Data were processed and analysed using the National Computational Infrastructure (NCI) facility super-computer at the Australian National University.
The Southern Thomson Orogen VTEMplus® AEM Survey dataset is available for free download via the Geoscience Australia website.
Southern Thomson Orogen VTEMplus® AEM survey.