Gawler Mineral Promotion Project

This project concluded 30 June 2006.

Project description

Geoscience Australia's Gawler Mineral Promotion project commenced in July 2000 and concluded in June 2006. The project formed part of the National Geoscience Accord between Geoscience Australia and State and Northern Territory Geological Surveys, in this case collaborating with the Department for Manufacturing, Innovation, Trade, Resources and Energy's predecessor, Primary Industries and Resources South Australia (PIRSA).

This multidisciplinary project involved production of new geological, geophysical, geochemical and metallogenic datasets in targeted regions of the Gawler craton. The planned outcomes were greater exploration investment in the craton and enhanced mineral exploration strategies in area selection and targeting.

The Gawler project has focussed on four modules of work, as detailed in the Gawler Craton Mineral Promotion Project Plan, 2000-04. They are:

• Module A: A framework for discovery of Proterozoic copper-gold (Cu-Au) in the eastern and central Gawler craton
• Module B: Regional controls on Au systems in the Archean Mulgathing Complex in the northwestern part of the craton
• Module C: Nickel-copper (Ni-Cu) potential of the Archean Harris Greenstone Belt in the central Gawler craton
• Module D: Recognition of Au and base-metal ore-forming systems through the regolith.

Most work in the project focussed on Module A, covering iron oxide Cu-Au (IOCG) systems in the Olympic Cu-Au province and Au systems in the Central Gawler Au province. Modules B, C and D were completed earlier in the project and results may be obtained from the Gawler Mineral Promotion Project Publications and from Gawler Craton Mineral Promotion: Maps and Data. For example, in Module C, products include a map in PDF format, and a paper on Late Archean Lake Harris Komatiite Central Gawler Craton, South Australia: Geological Setting and Geochemistry (Hoatson et al., 2005). Major products from Module D include datasets from Airborne Electromagnetic (AEM) surveys for the areas of the Challenger Au deposit, the Tunkillia Au prospect and the Moonta-Wallaroo Cu-Au district, as well as a Interpretation of airborne electromagnetic data: summary report on the Challenger Workshop (Lane and Worrall, 2002).

Many of the Gawler project results were reported at conferences such as the Gawler Craton: State of Play 2002 and 2004, and the 16th and 17th Australian Geological Congresses in 2002 and 2004. Final results were presented at a Workshop on IOCG systems of the Gawler craton in February 2006.

In the eastern Gawler craton, work within Module A centred on understanding the 3D structural and tectonic setting of IOCG mineralised systems in the Olympic Cu-Au province. This was achieved initially through 2D interpretations of basement geology and modelling of cross sections using the ModelVision software (see Direen et al, 2002, 16th AGC). Inversion modelling of regional magnetic and gravity data was then used to generate new 3D datasets including IOCG alteration distribution (see Eastern Gawler 3D VRML crustal model: Olympic Cu-Au province, and Constrained three-dimensional inversion of potential field data and crustal architecture of the Olympic Cu-Au province, South Australia). In 2003, around 200 line kilometres of deep crustal seismic reflection data was acquired in the vicinity of the Olympic Dam Cu-U-Au deposit and the data were released at the Gawler Seismic Workshop in August 2004 (see Lyons and Goleby, 2005). Studies of mineralisation and alteration in the Olympic Dam district, Moonta-Wallaroo district and Mt Woods Inlier were reported initially in a paper by Skirrow et al. (2002) and subsequently at various conferences. A map of the IOCG potential of the Gawler craton was released in 2006. The results of geochronological, fluid inclusion and stable and radiogenic isotope studies, along with their integration with the 3D geology, were published in a Special Issue of Economic Geology in 2007.

In the Central Gawler Au province, work within Module A focussed on the Tarcoola goldfield and the relationship between Au mineralisation and magmatism (see Budd et al, 2004 and Holm, 2004). The results were published in the Special Issue of Economic Geology (2007). Follow-up work on the IOCG mineral systems of the Gawler craton and their tectonic setting was published by Skirrow (2009), Hayward and Skirrow (2010) and Conor et al. (2010).

The work undertaken in the Gawler Mineral Promotion project formed a foundation for studies undertaken as part of the Onshore Energy Security Program.