|Project name:||Gawler Craton Airborne Survey|
|Project leader:||Laszlo Katona|
|Project group:|| Matthew Hutchens|
Yvette Poudjom Djomani (Geoscience Australia)
Clive Foss (CSIRO)
|Program:||Next Generation Copper Discovery Program|
The Gawler Craton in central South Australia is world renowned as one of the country’s leading exploration destinations. With an area of approximately 440,000 km2, the Gawler Craton is the oldest and largest geological province in South Australia and preserves a complex tectonic history that spans from c. 3200 Ma to 1450 Ma.
Exploration on the Gawler Craton is however complex, as a significant portion of the craton is obscured by significant layers of regolith, basin sediments and volcanic material, which can reach over 1 km thick in places.
The Gawler Craton Airborne Survey will capture approximately 1,800,000 line kilometres of new magnetic, radiometric and digital elevation geophysical data over an area of approximately 324,000 square kilometres. This new data will far surpass the current patchwork of surveys and provide a single, uniform dataset that will be fundamental in reinterpreting the geological structure of the Gawler Craton.
The data will be combined with other recent and ongoing data and research in the area including the Gawler Craton (WPA) and Northern Olympic Domain gravity surveys, the Eucla– Gawler Seismic and Magnetotelluric (MT) transects and the AusLAMP regional Magnetotelluric (MT) data.
The greater certainty of the geological structure and setting of the Gawler Craton provided by the data will allow explorers to better assess exploration opportunities in the area. The data will also feed into the precompetitive exploration workflow developed and executed by the GSSA and inform a new suite of value-added products directed at the exploration community.
Information about the survey regions, expected flight dates and latest flight plans can be found on the Gawler Craton Airborne Survey community information page.
The Gawler Craton is host to the world-class Olympic Dam Iron Ore Copper Gold (IOCG) deposit. Olympic Dam is the world’s largest uranium deposit containing approximately 36% of the world’s known uranium resources, as well as world-class resources of copper and gold.
The prospectivity of the Gawler Craton is further enhanced by several major copper mines including Prominent Hill, Carrapateena, Cairn Hill, Peculiar Knob, Mount Gunson, Hillside and Kanmantoo. Some major prospects include Khamsin, Emmie Bluff and Punt Hill.
Despite these mines and prospects, the Gawler Province is largely underexplored due primarily to its surficial cover of regolith masking the prospective basement, making exploration difficult. Statistical analysis of the type of ore bodies present in the Gawler Craton, compared to similar style deposits globally, suggests that there is an opportunity for more economic mineral discoveries to be found. For example, similar IOCG deposits in the Punta del Cobre IOCG province in Chile have realised many satellite deposits exist around the main ore body. These satellite ore bodies have not been found in South Australia.
Geological and mineral system models applied to the Province, underscore its potential to be highly prospective for regional, greenfields mineral exploration.
Geological settings that have application include:
- Cratonic margins, such as the western margin of the Gawler Craton, which are settings that typically host conduits for deeply sourced mineralising fluids and mineralisation traps
- Copper mineralisation in IOCG settings
- Gold deposits conforming to Challenger and Tunkillia styles
- Lead, zinc, and silver mineralisation (such as Menninnie Dam)
- Nickel-copper mineralisation related to the mafic rift sequence in the Fowler Domain
The use of geophysical techniques to ‘see-through’ the cover is vital for advancing our geological understanding of the Gawler Craton and for the identification of new and prospective terranes, and the discovery of new mineral deposits.
This project will capture new airborne magnetic, radiometric data as well as new laser altimeter digital elevation data for direct use by the exploration industry as well as being incorporated into the research programs of the GSSA. This new data will far surpass the current patchwork of surveys and provide a single, uniform dataset that will be fundamental in reinterpreting the geological structure of the Gawler Craton.
Data acquisition for such a large project must proceed in stages. The survey has been split into 10 distinct sub regions with all but Region 6, 7 and 10 further divided into two blocks each. It is anticipated that Stage One surveys will be flown in the period from January to June 2017 with Stage Two to commence Q3 2017 and Stage Three to commence Q1 2018. Regional investigations such as this are designed to set the foundations for the next generation of State resources industry growth and job creation in the services, supplies and manufacturing sectors. The information gathered will assist the government in making decisions on the development of its mineral and energy resources and provide new and updated geological information to the community.
This project is being undertaken in partnership with Geoscience Australia (a Division of the Commonwealth Department of Innovation and Science) under the National Collaboration Framework promoting State–Federal precompetitive geoscientific collaborative programs. The Geological Survey of South Australia in conjunction with CSIRO is releasing analytic enhancement images together with magnetic source depth estimates as part of the Gawler Craton Airborne Survey (GCAS) products. This endeavour to provide enhanced analytic and source depth products is a new development in exploration initiative programs, which have previously mostly provided raw flight-line and grid data.
- The Gawler Craton Airborne Survey will capture approximately 1,660,000 line kilometres of new geophysical data (magnetic, radiometric and digital elevation data) over an area of approximately 295,000 square kilometres.
- Data will be delivered through SARIG and the Gawler Craton Community Information Web Page, once it has been through the Quality Assurance/Quality Control (QA/QC) process (region by region).
- High quality magnetic data enhancements and depth solution enabling all explorers from the smallest to largest to work with high quality products, which they may not all have been able to produce themselves.
Schedule for information and product delivery
Delivery of Magnetic and Radiometric data sets (released block by block)
Data release to commence in Q3 2017 and continue until complete in Q1 2019
|Value-add to the data including incorporation into the State and Gawler Craton 3D model and State-wide geophysical maps will follow||Commencing in Q3, 2018|
|Geological Survey of South Australia Report Book: The Gawler Craton Airborne Survey, 2017 – 2018||Q2, 2019|