Laboratory partitioning of platinum-group elements (PGE) and gold with application to magmatic sulfide–PGE deposits

Fleet, Michael E.; Crocket, J. H.; Liu, Menghua; Stone, William E.

doi:10.1016/s0024-4937(99)00011-0

Cited by 174 publications

(97 citation statements)

References 29 publications

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“…In general the correspondence is good, and our results confirm the previously observed dependence of D mss/sulfide on the sulfur content of the melt (Barnes et al, 2001). Our results are similar to those of Ballhaus et al (2001) and Fleet et al (1993Fleet et al ( , 1999a. The presence of oxygen as a major anion in the sulfide liquid has had little effect on D mss/sulfide , and the sum of O ϩ S shows a weak control on D mss/sulfide of the relatively incompatible elements but little effect on D mss/sulfide of the compatible elements Ir, Ru, and Rh.…”

Section: Comparison To Previous Worksupporting

confidence: 92%

“…In several studies, investigators have equilibrated mss and sulfide melt in the systems Fe-Ni-S (Distler et al, 1977;Fleet and Stone, 1991;Fleet et al, 1999b), Fe-Ni-Cu-S (Fleet et al, 1993(Fleet et al, , 1999aFleet and Pan, 1994;Ebel and Naldrett, 1996;Li et al, 1996;Ballhaus et al, 2001;Barnes et al, 2001;Makovicky, 2002). In each case, results can be used to establish a partitioning coefficient D i for each element, defined as the concentration of the element in mss divided by its concentration in coexisting sulfide liquid (Fleet et al, 1999b).…”

Section: Previous Workmentioning

confidence: 99%

“…The calculation was performed using the batch equilibration equation of Campbell and Naldrett (1979) and sulfide/ silicate partition coefficients of 500 and 2000 for Ni and Cu, respectively, and 50,000 for Ir and Pt (cf., Peach et al, 1990;Peach and Mathez, 1993;Fleet et al, 1999a). The trend of possible initial sulfide liquids is shown with tick marks labeled at regular intervals of the mass ratio R between silicate and sulfide melts.…”

Section: Fractionation Of Natural Sulfide Magmasmentioning

confidence: 99%

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Partitioning of Cu, Ni, Au, and platinum-group elements between monosulfide solid solution and sulfide melt under controlled oxygen and sulfur fugacities

Mungall

Andrews

Cabri

et al. 2005

Geochimica et Cosmochimica Acta

202

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Abstract-We have performed six experiments in which we equilibrated monosulfide solid solution (mss) with sulfide melt in evacuated silica capsules containing solid buffers to fix oxygen and sulfur fugacity, at temperatures of 950°C, 1000°C and 1050°C at bulk concentrations of ϳ50 ppm for each of the PGE and Au, 5% Ni, and 7% Cu. Concentrations of O, S, Fe, Ni and Cu were determined by electron microprobe, whereas precious metal concentrations were determined by laser-ablation inductively-coupled mass spectrometry. Partition coefficients of all elements studied show minimal dependences on oxygen fugacity from the IW to the QFM buffers when sulfur fugacity is fixed at the Pt-PtS buffer. Cu, Pt, Pd and Au are strongly incompatible and Ru remains moderately to strongly compatible under all conditions studied. At all oxygen fugacities, at the Pt-PtS sulfur buffer, Ir and Rh remain highly compatible in mss. In the single run at both low oxygen and low sulfur fugacity Ir and Rh were found to be strongly incompatible in mss. At QFM and Pt-PtS the partition coefficient for Ni shows weak temperature dependence, ranging from 0.66 at 1050°C to 0.94 at 950°C. At lower oxygen and sulfur fugacity Ni showed much more incompatible behavior. Comparison with the compositions of sulfide ores from the Lindsley deposit of Sudbury suggests that the sulfide magma evolved under conditions close to the QFM and Pt-PtS buffers. The compatible behavior observed for Ni, Ir and Rh at Lindsley and most other magmatic sulfide deposits hosted by mafic rocks requires equilibration of mss and sulfide liquid at moderately high sulfur fugacity and low temperatures near to the solidus of the sulfide magma. We argue that this constraint requires that the sulfide magma must have evolved by equilibrium crystallization, rather than fractional segregation of mss as is commonly supposed.

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Section: Comparison To Previous Worksupporting

confidence: 92%

Section: Previous Workmentioning

confidence: 99%

Section: Fractionation Of Natural Sulfide Magmasmentioning

confidence: 99%

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Partitioning of Cu, Ni, Au, and platinum-group elements between monosulfide solid solution and sulfide melt under controlled oxygen and sulfur fugacities

Mungall

Andrews

Cabri

et al. 2005

Geochimica et Cosmochimica Acta

202

View full text Add to dashboard Cite

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“…Most of previous studies focusing on the behavior of gold in silicate melts aimed to determine the partitioning of gold between silicate liquid and sulfide phases (e.g., Bezmen et al, 1994;Fleet et al, 1996Fleet et al, , 1999Crocket et al, 1997;Jugo et al, 1999;Simon et al, 2007; 2008; Bell et al, 2009). Even though these experimental studies quantify the solubility of gold in the melt, the reported melt gold concentrations depend on the starting composition of the metal-doped sulfides.…”

Section: Introductionmentioning

confidence: 99%

Is gold solubility subject to pressure variations in ascending arc magmas?

Jégo

Nakamura

Kimura

et al. 2016

Geochimica et Cosmochimica Acta

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Magmas play a key role in the genesis of epithermal and porphyry ore deposits, notably by providing the bulk of ore metals to the hydrothermal fluid phase. It has been long shown that the formation of major deposits requires a multi-stage process, including the concentration of metals in silicate melts at depth and their transfer into the exsolved ore fluid in more superficial environments. Both aspects have been intensively studied for most of noble metals in subsurface conditions, whereas the effect of pressure on the concentration (i.e., solubility) of those metals in magmas ascending from the sublithospheric mantle to the shallow arc crust has been quite neglected. Here, we present new experimental data aiming to constrain the processes of gold (Au) dissolution in subduction-linked magmas along a range of depth. We have conducted hydrous melting experiments on two dacitic/adakitic magmas at 0.9 and 1.4GPa and ~1000°C in an end-loaded piston cylinder apparatus, under fO 2 conditions close to NNO as measured by solid Co-Pd-O sensors. Experimental charges were carried out in pure Au containers, the latter serving as the source of gold, in presence of variable amounts of H 2 O and, for half of the charges, with elemental sulfur (S) so as to reach sulfide saturation. Au concentrations in melt quenched to glass were determined by LA-ICPMS. When compared to previous data obtained at lower pressures and variable redox conditions, our results show that in both S-free and sulfide-saturated systems pressure has no direct, detectable effect on melt Au solubility. Nevertheless, pressure has a strong, negative effect on sulfur solubility. Since gold dissolution is closely related to the behaviour of sulfur in reducing and moderately oxidizing conditions, pressure has therefore a significant but indirect effect on Au solubility.The present study confirms that Au dissolution is mainly controlled by fO 2 in S-free melts and 3 by a complex interplay of fO 2 and melt S 2-concentration in sulfide-saturated melts, at given temperature. In addition, we propose that the transition from sulfide (S 2-) to sulfate (S 6+ ) species in melt is shifted towards more oxidizing conditions when pressure and the degree of melt polymerization increase. If this is true, this may have important consequences during mantle melting and magma ascent. In particular, if mantle melting occurred in moderately oxidizing conditions, a small degree of partial melting would allow the primary melts to become Au-enriched but the relatively high pressure would move the sulfide-sulfate transition to more oxidizing conditions, making the primary melts saturated with sulfide phases that would sequester gold from the melt. During magma ascent, the decreasing pressure would favour the destabilization of sulfides and the release of gold to the silicate melt. However, at shallow levels, decreasing pressure, magma evolution, and varying redox conditions would be continuously competing to concentrate or fractionate gold.

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“…Whole rock data (Godel and Barnes, in press) indicate that Pd is enriched in the J-M reef relative to the other PGE (reef Pd/Pt ratio of 3.3, Pd/Pt ratio above and below the reef <1). Assuming that the silieate/sulfide liquid partition coefficient for Pd and Pt are approximately equal (Fleet et al, 1999), this small-scale remobilization of Pd-Cu from the BMS on a small scale (mm to cm) is not likely to be the cause of Pd enrichment as all Pd would have been initially in the sulfide liquid and thus would have been modelled from whole rock data. In addition, only minor PGM alteration was observed in our section ( Fig.…”

Section: -Pt-fe Alloy: Role Of Sulfur Removalmentioning

confidence: 99%

Rôle des liquides sulfurés dans la formation des minéralisations riches en éléments du groupe du platine :

Godel¹

2007

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Laboratory partitioning of platinum-group elements (PGE) and gold with application to magmatic sulfide–PGE deposits

Cited by 174 publications

References 29 publications

Partitioning of Cu, Ni, Au, and platinum-group elements between monosulfide solid solution and sulfide melt under controlled oxygen and sulfur fugacities

Partitioning of Cu, Ni, Au, and platinum-group elements between monosulfide solid solution and sulfide melt under controlled oxygen and sulfur fugacities

Is gold solubility subject to pressure variations in ascending arc magmas?

Rôle des liquides sulfurés dans la formation des minéralisations riches en éléments du groupe du platine :

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