Yilgarn craton

The Archaean Yilgarn Craton is composed mainly of granite, with mafic, volcanic and sedimentary greenstone rocks. It is one of the world s principal mineral provinces, with considerable resources of primary and supergene Au, sulfide-hosted and lateritic nickel, bauxite, as well as a wide range of other commodities. 

Gray, D.J. 2001. Hydrogeochemistry in the Yilgarn Craton. Geochemistry Exploration, Environment, Analysis, 1, 253-264. 

Gray D.J. Noble R.R.P. 2007. Nickel hydrogeochemistry of the NE Yilgarn Craton, Western Australia. CSIRO Division of Exploration and Mining Restricted Report P2006/524. CRC LEME Open File Report 243R, 133 p. 

Cornelius, M., Robertson, I.D.M., Cornelius, A.J., Morris, P.A. 2008. Geochemical mapping of the deeply weathered western Yilgarn Craton of Western Australia, using laterite geochemistry. Geochemistry ... 

Abstract Mobile Au in soil has been postulated for many years. It has been used by the mineral exploration industry in areas of transported overburden as a vector towards buried deposits. Until now, the nature of this mobile Au has not been known or investigated. Soil samples from a colluvial area above the Bounty Deposit (Yilgarn Craton, Western Australia) investigated by analytical techniques including laser ablation inductively coupled mass spectrometry (LA-ICP-MS) and synchrotron x-ray fluorescence (SXRF) combined with X-ray absorption spectrometry (XAS) have allowed us to map the invisible Au in these soils and suggests that at least some of it occurs in an ionic form. 

Keywords gold, synchrotron XRF, mineral exploration, ionic gold, Yilgarn Craton... 

Soil samples were collected systematically down a 2 m deep colluvial soil profile located over Au mineralisation at the Bounty Gold Deposit (Yilgarn Craton, Western Australia), prior to mining. Bulk samples were analysed by ICP-AES, ICP-MS and XRD and further sub-sampled and analysed to ensure that they contained detectable Au prior to detailed analysis by LA-ICP-MS, SXRF and x-ray adsorption near edge spectrometry (XANES). 

Studies of 2.65 Ga gold systems in the Yilgarn Craton, Western Australia, have emphasised the interaction of intrinsically reduced (CH4 H2 N2 HCI) and oxidized (CO2 SO2) anhydrous fluids as well as hydrous fluids in deposit formation. Carbonate veins have between -4 and -6 %o, typical of mantle values and primary sulfate have of 8 to 12 %o. 

Redox gradients in Au systems of the Yilgarn Craton, Western Australia have been mapped across gold lodes and at camp to district scales using C and S isotopes combined with alteration studies. These gradients can be related to the interplay of oxidized and reduced... 

Swager, C. P., Goleby, B. R., Drummond, B. J., Rattenbury, M. S. Williams, P. R. 1997. Crustal structure of granite-greenstone terranes in the Eastern Goldfields, Yilgarn Craton, as revealed by seismic reflection profiling. Precam-brian Research, 83, 43-56. 

Wilde, S. A., Middleton, M. F. Evans, B. J. 1996. Terrane accretion in the southwestern Yilgarn Craton evidence from a deep seismic crustal profile. Precambrian Research, 78, 179-196. 

The oldest known terrestrial materials are 4.1-4.4Ga detrital zircons from the Mount Narryer area of western Australia (Froude et al., 1983). The first locality to be shown to host extremely ancient zircons (4.1-4.2Ga) was a sequence of highly metamorphosed quartzites, conglomerates, and pelites from Mount Narryer, at the northwestern edge of the Yilgarn Craton in western Australia. Subsequent discoveries, in a less metamorphosed sequence of sediments from the Jack Hills, some 60 km away identified even older zircons, some 4.28 Ga old (Compston Pidgeon, 1986). Recently, Wilde et al. (2001) reported a zircon grain with an age of 4.404 0.008 Ga (Fig. 1.10). To date this is the... 

The Mount Weld carbonatite dates from the Proterozoic (approximately 2025 Ma ago) and is emplaced in the Yilgarn Craton (Hoatson et al. 2011). The carbonatite is covered by a thick lateritic soil, which in its turn is covered by lacustrine and alluvial sediments (Lottermoser 1990). The Mount Weld deposit occurs in the weathered layer. 

---