The Distribution of PGE and the Role of Arsenic as a Collector of PGE in the Spotted Quoll Nickel Ore Deposit in the Forrestania Greenstone Belt, Western Australia

We describe similar assemblages of minerals found in two placers in Russia, both probably derived from an ophiolitic source. The first is located along the River Rudnaya in the western Sayan province, Krasnoyarskiy kray, and the second pertains to the Miass placer zone, Chelyabinsk oblast, in the southern Urals. The platinum-group element (PGE) mineralization in both cases is mostly (at least 80%) represented by alloy minerals in the system Ru–Os–Ir, in the order of occurrence osmium, ruthenium and iridium. The remainder consists of Pt–Fe alloys and species of PGE sulfides, arsenides, sulfarsenides, etc. The associated olivine and amphiboles are supermagnesian, and the chromian spinel has a high Cr# value. The observed enrichment in Ru, typical of an ophiolitic source, may be due to high-temperature hydrothermal equilibration and mobilization in the ophiolite, as is the enrichment in Mg and Cr. Low-temperature replacement of the alloys led to the development of laurite, sulfoarsenides and arsenides. Some placer grains in both suites reveal unusual phases of sulfo-arsenoantimonides of Ir–Rh, e.g. the unnamed species (Rh,Ir)SbS and (Cu,Ni)1+x(Ir,Rh)1–xSb, where x = 0.2, and rhodian tolovkite, (Ir,Rh)SbS. Two series of natural solid-solutions appear to occur in the tolovkite-type phases. Among the oddities in the Rudnaya suite are globules of micrometric PGE sulfides, crystallites of platinum-group minerals, amphibole, and chalcopyrite bearing skeletal micrometric monosulfide-like compounds (Cu,Pt,Rh)S and (Pd,Cu)S1–x. Pockets of fluxed evolved melt seem to have persisted well below the solidus of the host Pt3Fe-type alloy.

show abstract

“…These textures clearly imply a trend of increasing arsenic fugacity during crystallization (cf. Prichard et al ., 2013).…”

Section: Analytical Methods and Resultsmentioning

confidence: 99%

Ophiolite-related associations of platinum-group minerals at Rudnaya, western Sayans and Miass, southern Urals, Russia

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Magmatic arsenides that evidently crystallized directly from sulfide or associated arsenide melt have been described in the following studies: at the Carratrace and the Arroyo de la Cueva deposits in Spain (Hem et al , 2001), Beni Bousera in Morocco (Gervilla et al , 1996; Pina et al , 2013), the Ni-Cu deposit at Las Aguilas in Argentina (Gervilla et al , 1997), Serrania de Ronda in Spain (Pina et al , 2015), the Copper Cliff North Area, Dundonald Beach South and Creighton Ni-Cu-PGE deposits in Canada (Szentpeteri et al , 2002; Hanley, 2007; Dare et al , 2010 a ), and the Rosie nickel prospect and the Spotted Quoll deposits in Western Australia (Godel et al , 2012; Prichard et al , 2013). Only a small portion of these studies present the results of LA-ICP-MS analyses on arsenides, but the few that do all agree that magmatic Ni-Co arsenides contain elevated concentrations of PGEs.…”

Section: Introductionmentioning

confidence: 99%

“…Only a small portion of these studies present the results of LA-ICP-MS analyses on arsenides, but the few that do all agree that magmatic Ni-Co arsenides contain elevated concentrations of PGEs. Arsenides acted as collectors for the PGEs, particularly Pd and Pt, with an average concentration of 257 ppm Pd, 536 ppm Pt at the Rosie prospect (Western Australia, Godel et al (2012), 234 ppm Pd, 83 ppm Pt at the Spotted Quoll nickel deposit (Western Australia; Prichard et al , 2013), and 52 ppm Pd, 167 ppm Pt at the Dundonald Beach nickel deposit, Canada (Hanley, 2007). Gold concentration of these magmatic arsenides vary widely between different deposits, ranging from an average of 0.11 ppm Au at Spotted Quoll (Prichard et al , 2013) to 0.708 ppm Au at Rosie (Godel et al , 2012).…”

Section: Introductionmentioning

confidence: 99%

Platinum-group element and gold contents of arsenide and sulfarsenide minerals associated with Ni and Au deposits in Archean greenstone belts

et al. 2018

View full text Add to dashboard Cite

Post-magmatic alteration of certain magmatic Ni sulfide ores in Western Australia, the Miitel deposit and the Sarah's Find prospect, produced Ni–As–PGE haloes around massive sulfides. A study of the composition of arsenide grains from these hydrothermal haloes, along with arsenides from various magmatic and hydrothermal mineralized environments in other localities, was conducted in order to compare their composition, and assess their potential use as indicator minerals for exploration vectoring, as well as to gain knowledge on their crystallization history. Concentrations in trace elements such as platinum-group elements (PGEs), Au and other metals was obtained by laser ablation inductively coupled plasma mass spectroscopy analyses. Results show that variations in PGEs and Au compositions can be related to the magmaticvs.hydrothermal origin of the grains; and to their provenance from deposits enriched in either Ni, Au or both. Magmatic NiCoFe sulfarsenides have strongly correlated, high IPGE (Os, Ir, Ru, Rh) contents up to 100 ppm Ir, compared with maximum values in hydrothermal sulfarsenides of ~1 ppm. Gold in hydrothermal sulfarsenides from Au-mineralized ultramafic rocks extends up to 500 ppm, with typical values of 3–30 ppm; similar values are also found in nickeline (also called niccolite). These results suggest that nickel arsenides could potentially be used as indicator minerals for nickel and gold exploration. Trace-element contents of arsenide grains in shear zones could be used to deduce the presence of Ni or Au mineralization upstream in the fluid pathway.

show abstract

“…The potential importance of arsenide as a collector of the PGE in magmatic and hydrothermal systems has been well-documented (Hanley, 2007; Dare et al , 2010; Godel et al , 2012; Le Vaillant et al , 2015; Prichard et al , 2013; Helmy et al , 2013; Helmy and Bragagini, 2017), and though arguably not completely understood, it is known that As-rich deposits can exhibit very high PGE grades. Arsenic is enriched in intermediate solid solution (iss) during cooling (Holwell and McDonald, 2010), and there is a broad spectrum of Pd and Pt-rich arsenide phases that attest to the ease at which bonding with the metals occurs.…”

Section: Discussionmentioning

confidence: 99%

Platinum-group element remobilization and concentration in the Cliff chromitites of the Shetland Ophiolite Complex, Scotland

et al. 2018

View full text Add to dashboard Cite

The ~492 Ma Shetland Ophiolite Complex contains an extensive mantle section, within which numerous podiform chromitite bodies formed during melt percolation in a supra-subduction zone setting. One of the Shetland ophiolite chromitite localities has an unusual style of platinum-group element (PGE) mineralization. Specifically, the Cliff chromitite suite has relatively high (>250 ppm) Pt plus Pd, compared to other chromitites in the Shetland Ophiolite Complex. In this study, we apply petrographic observation, mineral chemistry and novel X-ray microtomography data to elucidate the petrogenesis of PGE-bearing phases at Cliff. The combined datasets reveal that the PGE at Cliff have probably been fractionated by an As-rich fluid, concentrating Pt and Ir into visible (0.1–1 µm) platinum-group minerals (PGM) such as sperrylite and irarsite, respectively. The high (>1 ppm) bulk-rock concentrations of the other PGE (e.g. Os) in the Cliff chromitites suggests the presence of abundant fine-grained unidentified PGM in the serpentinized groundmass. The spatial association of arsenide phases and PGM with alteration rims on Cr-spinel grains suggests that the high Pt and Pd abundances at Cliff result from a late-stage low-temperature (e.g. 200–300°C) hydrothermal event. This conclusion highlights the potential effects that secondary alteration processes can have on modifying and upgrading the tenor of PGE deposits.

show abstract

The Distribution of PGE and the Role of Arsenic as a Collector of PGE in the Spotted Quoll Nickel Ore Deposit in the Forrestania Greenstone Belt, Western Australia

Cited by 22 publications

References 40 publications

Ophiolite-related associations of platinum-group minerals at Rudnaya, western Sayans and Miass, southern Urals, Russia

Ophiolite-related associations of platinum-group minerals at Rudnaya, western Sayans and Miass, southern Urals, Russia

Platinum-group element and gold contents of arsenide and sulfarsenide minerals associated with Ni and Au deposits in Archean greenstone belts

Platinum-group element remobilization and concentration in the Cliff chromitites of the Shetland Ophiolite Complex, Scotland

Contact Info

Product

Resources

About