Globally supracrustal sedimentary rocks are known to preferentially precipitate gold between 2400 Ma and 1800 Ma (Goldfarb et al. 2001). The Palaeoproterozoic Tanami and Pine Creek regions of Northern Australia host one world-class gold deposit and many other gold deposits in anomalously iron-rich marine mudstones (Figure 1). New fluid-rock modelling at temperatures between 275 - 350C suggest a strong correlation between gold grade and these Palaeoproterozoic iron-rich, fine-grained sedimentary rocks.

Australian Gold Resources Map, 1:10 000 000, December 2006 Version

Proterozoic Gold Mineralising events on Australian Proterozoic Georgions base, 1:5 000 000 October 2007 Version (PDF and JPG)

No abstract available

Geological regions with abnormally high endowment in metals appear to have resulted from the fortunate juxtaposition in space and time of numerous, possibly exceptional, processes. The gold mineral system of the Eastern Goldfields Superterrane (EGST) is an example. In order to understand why this is so, we have taken an approach that considers the mineral system as a series of integrated components known as the Five Questions: viz 1) geodynamics; 2) architecture; 3) sources & reservoirs; 4) drivers & pathways; and, 5) depositional mechanisms. In order to better understand these components and the geological processes that define them, a range of scales needs to be considered. However at each scale the relative benefits of considering any one of the five components varies. Ultimately the aim is to use this scale-integrated process-based understanding for prediction. Understanding why a region is particularly endowed or a deposit so rich is important but only half the question. The other half is where is the next favourable region and/or camp and deposit? In this regard, we 'Answer' the Five Questions.

A ~400 km long deep crustal reflection seismic survey was carried out in Central Victoria, Australia, in 2006. It has provided information on crustal architecture across the western Lachlan Orogen and has greatly added to the understanding of the tectonic evolution. The east-dipping Moyston Fault is confirmed as the suture between the Delamerian and Western Lachlan orogens and is shown to extend down to Moho. The Avoca Fault, which is the boundary between the Stawell and Bendigo zones, is a west-dipping listric fault that intersects the Moyston Fault at a depth of about 22 km, forming a V-shaped geometry. Both the Stawell and Bendigo structural zones can be broadly divided into a lower crustal region of interlayered and imbricated metavolcanic and metasedimentary rocks and an upper crustal region of tightly-folded metasedimentary rocks. The Stawell Zone was probably part of a Cambrian accretionary system along the eastern Gondwana margin and mafic rocks may have been partly consumed by Cambrian subduction. Much of the Early Cambrian oceanic crust beneath the Bendigo Zone has not been subducted but is preserved as a crustal-scale imbricate thrust stack. The seismic data have shown that the 'thin-skinned' structural model appears to be valid for much of the Melbourne Zone whereas the Stawell and Bendigo zones have a 'thick-skinned' structural style. Internal faults in the Stawell and Bendigo zones are mostly west-dipping listric faults, which extend from the surface, with listric geometries, to near the base of the crust. The Heathcote Fault Zone, which forms the boundary between the Bendigo and Melbourne zones, extends to at least 20 km, and possibly to the Moho. A striking feature in the seismic data is the markedly different seismic character of the mid to lower crust of the younger Melbourne Zone. The deep seismic reflection data for the Melbourne have revealed a multilayered crustal structure that supports the Selwyn Block model.

A map showing the distribution of selected mines and mineral depsosits for a range of commodities. It also shows the distribution of petroleum resources in basic form. The map base is the Radiometric Map of the Australian Region

The development of a regional stratigraphy in Palaeoproterozoic basins within the Tanami region, Northern Australia has been hindered by the difficulty of discriminating sedimentary units and facies across isolated and poorly exposed basins. A regional stratigraphy is important as it provides constraints on sedimentary basin evolution and assists in gold exploration, as mineralisation is more abundant in certain rock formations. Based on geochemistry, five main sedimentary basin events have been identified in the Tanami region, ranging from poorly mixed local sedimentary sources to well mixed distal sources. Within the basins, major gold bearing lithologies are characterised by mafic source indicators: (1) high Cr/Th ratios; (2) low Th/Sc ratios; (3) low (La/Yb)N ratios relative to Post-Archaean Average Shale; (4) Eu anomaly equal to ~1 and, (5) distinctive ranges in initial Nd values, which together define vertical stratigraphic position. Potential future exploration target areas have been identified in the Tanami region at the Cashel and Sunline prospects using these geochemical parameters.

The purpose of the presentation was to show mineral explorers how recent results from the Gawler Mineral Promotion Project may be used in their quest for blind iron-oxide copper gold (IOCG) deposits in the Gawler Craton. The Gawler Project ran from late 2000 to early 2006. The project developed new methods of exploring prospective basement beneath deep cover.

A map showing the distribution of selected mines and mineral depsosits for a range of commodities. It also shows the distribution of petroleum resources in basic form. The map base is the Gravity Map of the Australian Region.