Abstract attached

Abstract The Palaeoproterozoic, from 2100 to 1800 Ma, is recognised as the third largest period of orogenic gold mineralization. In contrast to earlier Archean orogenic gold episodes which occur predominantly in greenstone terranes, supracrustal sedimentary rocks became increasingly important as hosts in the Palaeoproterozoic. Unusually iron-rich 1840 Ma marine mudstones in the Tanami region host one world class gold deposit and many other gold deposits. Fluid-rock modelling at 350°C suggest a strong correlation between gold grade and these iron-rich, fine-grained sedimentary rocks and suggest that gold may precipitate in the iron-rich sediments in the first stage of mineralization, before remobilization of the gold further enhances the grade of the deposit. New regional stratigraphic correlations for similar iron-rich rocks to those in the Tanami region are suggested with ~1860 Ma gold-bearing stratigraphy in the Pine Creek region and potentially with ~1860 Ma host rocks in the Tennant region. These Northern Australian Palaeoproterozoic iron-rich sedimentary rocks could be linked globally to similar aged iron-rich and gold-bearing sedimentary rocks in Homestake, U.S., Ghana, West Africa and elsewhere. From about 2400 to 1800 Ma the Palaeoproterozoic is also marked by the occurrence of mainly Superior-style BIF's, which are attributed to the progressive oxygenation of the deep oceans resulting in the global scrubbing of iron from the oceans. The high iron concentrations noted in pre-1800 Ma marine sediments in Northern Australia could also be related to this same process and help explain the anomalous concentration of orogenic Au deposits from 2100 to 1800 Ma.

No abstract available

This report is compiled of four separate reports. (1) "Note on the Application by the Chamber of Mines, W.A." Yield, production, industry costs, and the subsidy proposal are discussed in this report. (2) "Proposal for a Subsidy to the Gold Mining Industry". This report is concerned with details of the economic position of the mines and Western Australian gold industry as a whole. (3) "Supplementary Report on the Proposal for a Subsidy to the Gold Mining Industry". This report summarises the findings of the earlier enquiry into the position of the Western Australian gold industry. (4) "The General Effect on Gold Mine Surplus of Assistance based on Production". The object of this note is to outline briefly some of the principles which require consideration in determining whatever form of assistance may be decided.

At the Sandpiper gold deposit in the Tanami region of northern Australia sericite is intimately intergrown with arsenopyrite in gold-bearing quartz veins and breccias, suggesting sericite crystallisation synchronous with gold-bearing fluid flow. This ore-stage sericite yields a 40Ar/39Ar plateau age of 1785 ± 16 Ma (1?? including all known systematic uncertainties). Recalculation using revised and more precise values for the 40K decay constants and the age of the Fish Canyon Sanidine standard shifts the age to 1792 ± 6 Ma (1???including all known systematic uncertainties). Given the possibility of post-mineralization isotopic resetting this age can be conservatively interpreted as a minimum constraint on the timing of gold deposition although, given local geological relationships and estimates for the argon retentivity of white mica, we consider complete isotopic resetting to be unlikely. The preferred interpretation is, therefore, that the sericite 40Ar/39Ar age indicates the timing of gold mineralization. The sericite age accords with a limited dataset of 207Pb/206Pb xenotime ages of ~1800 Ma from other gold deposits in the Tanami region, interpreted as mineralization ages. The agreement between independently-derived ages from several gold deposits lends support for a widespread gold-mineralizing event at ~1800 Ma in the Tanami region.

Gold Mining Lease 1075 is situated at the head of Rowlands Creek, a tributary of Barola Creek. The workings are on the hillside just south of the head of Rowlands Creek and approximately five miles west-south-west from Kainantu Sub-District Office and Airstrip in the Eastern Highlands of New Guinea. The elevation of the workings is approximately 6,200 feet above sea-level. The area was examined by the writer in April, 1953. [The history and development of the lease, transport and resources, general geology, ore geology, the occurrence of the gold, and further prospects, are discussed in this report].

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 georegions of Australia

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

Geoscience Australia has been acquiring deep crustal reflection seismic transects throughout Australia since the 1960s. The results of these surveys have motivated major interpretations of important geological regions, contributed to the development of continental-scale geodynamic models and improved understanding about large-scale controls on mineral systems. Under the Onshore Energy Security Program, Geoscience Australia has acquired, processed and interpreted over 5000 km of new seismic reflection data. These transects are targeted over geological terrains in all mainland states which have potential for hydrocarbons, uranium and geothermal energy systems. The first project was undertaken in the Mt Isa and Georgetown regions of North Queensland. Interpretations of these results have identified several features of interest to mineral and energy explorers: a previously unknown basin with possible hydrocarbon and geothermal potential; a favourable setting for iron oxide uranium-copper-gold deposits; and, a favourable structural setting for orogenic gold deposits under basin cover. Other geophysical data were used to map these features in 3D, particularly into areas under cover. Seismic imaging of the full thickness of the crust provides essential, fundamental data to economic geologists about why major deposits occur where they do and reduces risk for companies considering expensive exploration programs under cover.