Fluid inclusion evidence on the origin of some Australian unconformity-related uranium deposits

An evaporated seawater origin for the ore-forming brines in unconformity-related uranium deposits (Athabasca Basin, Canada): Cl/Br and δ37Cl analysis of fluid inclusions

“…The Kombolgie sub-Basin (McArthur Basin), Northern Territory, Australia, hosts very similar unconformity-related uranium deposits that were formed from comparable NaCl-rich and CaCl 2 -rich brines (Ypma and Fuzikawa, 1980;Wilde et al, 1989;Derome et al, 2003Derome et al, , 2007Polito et al, 2004Polito et al, , 2005. Continuing their use of crush-leach techniques, Derome et al (2007) found molar Cl/Br ratios between 151 and 220 in fluid inclusion leachates from quartz veins.…”

The calculated solubility of platinum and gold in oxygen-saturated fluids and the genesis of platinum-palladium and gold mineralization in the unconformity-related uranium deposits

“…There is very little information on the nature of gold and PGE in the unconformity-related uranium deposits, though the close spatial association between uranium, gold and PGE in some uranium deposits of the Alligator Rivers Uranium Field has been stressed by Needham (1987) and Wilde et al (1989b). The characteristic features discussed in the following section are based on the description of the unconformity-related uranium deposits in the Athabasca basin in Canada and in the Alligator Rivers Uranium Field in Australia.…”

“…Native gold in the Koongarra and Jabiluka deposits forms inclusions and veins in uraninite, suggesting overlap in the deposition of uranium and gold. At Jabiluka gold is accompanied by tellurides of nickel and lead (Wilde et al, 1989b) and PGE are present in the form of subeconomic concentrations of palladium. Although the mineralogy and paragenesis of palladium is not known, the distribution of gold and palladium values is very similar (Wilde et al 1989 b).…”

“…CaC12) and contains methane and minor N2. The ore-deposition is thought to have taken palce at temperatures between 150 and 170~ due to mixing of a metal-bearing oxidized fluid with a more reduced fluid (Wilde et al 1989b).…”

Reduction kinetics of aqueous U(VI) in acidic chloride brines to uraninite by methane, hydrogen or C-graphite under hydrothermal conditions: Implications for the genesis of unconformity-related uranium ore deposits

“…Bray et al (1988) proposed that interaction of basinal brines with sulfide-bearing graphitic metasediments could have produced CO 2 ± CH 4 ± H 2 S ± H 2 gases. Indeed, traces of reduced gases such as CH 4 , C 2 H 6 , or H 2 were detected by Raman spectroscopy in fluid inclusions from URU deposits (Wilde et al, 1989;Derome et al, 2003aDerome et al, ,b, 2005. Hydrogen sulfide, from alteration of sulfide minerals, is also a potential reducing agent of U(VI) (aq) (Spirakis, 1981;Cheney, 1985;Beyer et al, 2010).…”