Noble metal nanoclusters and nanoparticles precede mineral formation in magmatic sulphide melts

Helmy, Hassan M.; Ballhaus, Chris; Fonseca, Raúl O. C.; Wirth, Richard; Nagel, T.; Tredoux, M.

doi:10.1038/ncomms3405

Cited by 102 publications

(55 citation statements)

References 35 publications

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“…4e, j). The behavior of Te, Bi, As and Sb contrasts with that of Se which remains in solid solution in sulfide, by generally fractionating into immiscible telluride/bismuthide/arsenide and possibly antimonide melts on cooling and crystallization of a sulfide liquid (Helmy et al 2010(Helmy et al , 2013aHolwell and McDonald 2010;Prichard et al 2013). Furthermore, these melts sequester precious metals more effectively than sulfide melt (Helmy et al 2010).…”

Section: Precious and Semimetal Characteristics Of The Sulfidesmentioning

confidence: 94%

“…Furthermore, these melts sequester precious metals more effectively than sulfide melt (Helmy et al 2010). Although this appears to include a significant amount of Te in solid solution in sulfide, the high concentrations of Te at the base of the Cu zone may also represent the presence of some immiscible telluride melts associated with the sulfides in this zone (e.g., Helmy et al 2010Helmy et al , 2013a; though it is worth noting the dominant mineralogy of the PGE and Au remain as alloys.…”

Section: Precious and Semimetal Characteristics Of The Sulfidesmentioning

confidence: 99%

“…Microinclusions of other minerals are recorded as small spikes in individual elements across the TRA profile. Typically, in magmatic sulfide minerals, microinclusions are commonly PGM such as PGEbearing tellurides, bismuthides and arsenides (e.g., Holwell and McDonald 2007), which form due to the tendency for telluride, bismuthide, arsenide melts to separate from the sulfide liquid on cooling, sequestering PGE and forming PGM (e.g., Helmy et al 2010Helmy et al , 2013aHolwell and McDonald 2010).…”

Section: La-icp-ms Analysis Of Sulfide Droplets In the Platinova Reefmentioning

confidence: 99%

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Extreme enrichment of Se, Te, PGE and Au in Cu sulfide microdroplets: evidence from LA-ICP-MS analysis of sulfides in the Skaergaard Intrusion, east Greenland

Holwell

Keays

McDonald

et al. 2015

Contrib Mineral Petrol

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evidence implies that there is no significant post-magmatic hydrothermal S loss and that the metal profiles are essentially a function of magmatic processes. We propose that to generate these extreme precious and semimetal contents, the sulfides must have formed from an anomalously metal-rich package of magma, possibly formed via the dissolution of a previously PGE-enriched sulfide. Other processes such as kinetic diffusion may have also occurred alongside this to produce the ultra-high tenors. The characteristic metal offset pattern observed is largely controlled by partitioning effects, producing offset peaks in the order Pt+Pd>Au>Te>Se>Cu that are entirely consistent with published D values. This study confirms that extreme enrichment in sulfide droplets can occur in closed-system layered intrusions in situ, but this will characteristically form ore deposits that are so low in sulfide that they do not conform to conventional deposit models for Cu-Ni-PGE sulfides which require very high R factors, and settling of sulfide liquids.

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Section: Precious and Semimetal Characteristics Of The Sulfidesmentioning

confidence: 94%

Section: Precious and Semimetal Characteristics Of The Sulfidesmentioning

confidence: 99%

Section: La-icp-ms Analysis Of Sulfide Droplets In the Platinova Reefmentioning

confidence: 99%

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Extreme enrichment of Se, Te, PGE and Au in Cu sulfide microdroplets: evidence from LA-ICP-MS analysis of sulfides in the Skaergaard Intrusion, east Greenland

Holwell

Keays

McDonald

et al. 2015

Contrib Mineral Petrol

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“…(phylum Apicomplexa, family Cryptosporidiidae) are coccidian protozoa affecting the gastrointestinal tract in several mammalian and amphibian species and only the lungs in birds (Helmy et al, 2013). Some of the members of this family possess also well expressed zoo-anthropogenic potential (Castro-Hermida et al, 2002).…”

mentioning

confidence: 99%

Clinical and morphological investigations in a spontaneous cryptosporidium enteritis outbreak in calves

Kalkanov¹,

Dinev²,

Dimitrov³

et al. 2016

BJVM

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SummaryKalkanov, I., I. Dinev, K. Dimitrov & P. Iliev, 2016. Clinical and morphological investigations in a spontaneous Cryptosporidium enteritis outbreak in calves. Bulg. J. Vet. Med., 19, No 4,[334][335][336][337][338][339] The purpose of this report was to present the results of histopathological examination during the course of a natural Cryptosporidium parvum outbreak, as well as the morphology of cells infiltrating affected gastrointestinal tract areas in newborn calves. The study included 18 calves exhibiting a marked diarrhoeic syndrome, between 1 and 8 days of age. Sporulated C. parvum oocysts were demonstrated in faecal smears stained by the method of Henriksen. Coproantigens of C. parvum were detected by the rapid Rainbow calf scour 5 BIO K 306 test. Gross lesions were mainly present in the gastrointestinal tract, together with inflammation in regional mesenteric lymph nodes. Microscopic histopathological lesions consisted mainly in desquamative catarrh of intestinal mucosa and intestinal villous atrophy. The affected intestinal epithelium contained multiple Cryptosporidium spp. forms at different stage of the life cycle. The results from histopathological studies of the outbreak allowed confirming some main morphogenetic features of the disease caused by C. parvum in newborn and growing calves.

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“…Recently, an increasing number of studies have reported the formation of nanocluster precursors and nanoparticles of PGEs under magmatic conditions (Bockrath et al 2004a;Ballhaus et al 2006;Finnigan et al 2008;Kogiso et al 2008;Helmy et al 2013;Wirth et al 2013;Junge et al 2015). In their pioneering studies on the PGE-chromite-sulphide system, Bockrath et al (2004a) and Ballhaus et al (2006) documented the formation of nanoparticles of metallic Ru and Ir below the liquidus temperature (1200-1360 °C) in low-pressure (0.5 GPa) experiments.…”

Section: Introductionmentioning

confidence: 95%

Thermal metamorphism of mantle chromites and the stability of noble-metal nanoparticles

Gonzáléz-Jiménez

Reich

Camprubí

et al. 2015

Contrib Mineral Petrol

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event, confirming previous thermodynamic predictions. Understanding these complex features is of particular interest due to the fact that changes in temperature and variable degrees of fluid/rock interaction during metamorphism and intrusion have also significantly affected the chromitehosted IPGE carrier phases. Here, we propose that the metamorphic fluids involved in the hydrous metamorphism have caused the desulphurization of laurite RuS 2 , releasing minute particles of Ru-Os-Ir alloys <50 nm in diameter. The following short-lived thermal event that promoted dehydration in the chromitite had the opposite effect on nanoparticle stability, producing a significant coarsening of metal nanoparticles to dimensions larger than a micron. Based on such observations, we argue that IPGE nanoparticles can be exsolved and grown (or coarsen) from sulphide matrices during prograde metamorphism or heating and not exclusively upon cooling under magmatic conditions as it has been previously suggested. These results provide new insights on the relevant role of temperature and nanoparticle-host interaction phenomena in natural systems, shedding new light on the kinetic controls of nano-to micronscale IPGE particle distributions during metamorphism. Abstract The Loma Baya complex in south-westernMexico is a volume of chromitite-bearing oceanic mantle that records a complex metamorphic history, defined by a first stage of hydrous metamorphism overprinted by a short-lived thermal event associated with an Eocene granite intrusion. During the hydrous metamorphism, the primary magmatic chromite-olivine assemblage was replaced by a secondary, porous intergrowth of Fe 2+ -rich chromite and chlorite. The heat supplied by an Eocene-age granite intrusion reversed the hydration reaction, producing chromite rims with perfectly developed crystal faces. This thirdgeneration chromite is in equilibrium with highly magnesian (neoformed) olivine and defines a chemical trend analogous to the original magmatic one. The preservation of both reactions in the Loma Baya chromitite provides compelling evidence that the hydration of chromite can be reversed by either prograde metamorphism or any heating Communicated by Othmar Müntener. Electronic supplementary materialThe online version of this article (

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Noble metal nanoclusters and nanoparticles precede mineral formation in magmatic sulphide melts

Cited by 102 publications

References 35 publications

Extreme enrichment of Se, Te, PGE and Au in Cu sulfide microdroplets: evidence from LA-ICP-MS analysis of sulfides in the Skaergaard Intrusion, east Greenland

Extreme enrichment of Se, Te, PGE and Au in Cu sulfide microdroplets: evidence from LA-ICP-MS analysis of sulfides in the Skaergaard Intrusion, east Greenland

Clinical and morphological investigations in a spontaneous cryptosporidium enteritis outbreak in calves

Thermal metamorphism of mantle chromites and the stability of noble-metal nanoparticles

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