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, David A.; Keays, Reid R.; McDonald, Iain; Williams, Megan R.

doi:10.1007/s00410-015-1203-y

Cited by 49 publications

(32 citation statements)

References 78 publications

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“…Ag varies between 0.01-0.07 wt % with a maximum amount of 0.11 wt% (in Konya) whereas Au is higher showing higher values in the Usak-Güre basin (Au median=0.14-0.24 wt %) compared to the rest (Au median=0.04-0.05 wt %). These unusually high sporadic values of Ag and Au have been attributed by previous studies to clustering and nugget effects of noble metals (e.g.Savelyev et al, 230 2018, Zelenski et al, 2017, Holwell et al, 2015, Holwell and McDonald, 2010. A possible Au nugget occurrence is shown in figure 4viii for type-3 sulphides of Beydagi.…”

supporting

confidence: 56%

“…This sulphide type occurs only within Fe-oxides, mostly in Tirich magnetite with occasional ilmenite exsolution lamellae. Their angular shape indicates that the solution was trapped initially as a Cu-rich liquid (Chang and Audétat, 2018) which solidified into an iss following the host mineral crystallisation planes and later unmixed (see also Georgatou et al, 2018, Holwell et al, 2015. In addition to the relatively low temperature ranges compared to the first stage sulphides (<330°C, see Fig.10), other 290 petrographic and compositional arguments for considering this latter stage as a later stage are the following: (i) the unique occurrence in magnetite, a late crystallising mineral relative to olivine and pyroxene (hosting the first stage sulphide types-1 and 2) and (ii) the more dominant occurrence of voids around the Cu-rich sulphides https://doi.org/10.5194/se-2019-106 Preprint.…”

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confidence: 99%

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Magmatic sulphides in high-K calc-alkaline to shoshonitic and alkaline rocks

Georgatou

Chiaradia

2019

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Abstract. We investigate in both mineralised and barren systems the occurrence and chemistry of magmatic sulphides and their chalcophile metal cargo behaviour during evolution of compositionally different magmas in diverse geodynamic settings. The investigated areas are: (a) the Miocene Konya magmatic province (hosting the Doganbey Cu-Mo and Inlice Au-epithermal deposits) (Post-Subduction) and (b) the Miocene Usak basin (Elmadag, Itecektepe and Beydagi volcanoes, the latter associated with the Kisladag Au porphyry) in Western Turkey (Post-Subduction). For comparison we also investigate (c) the barren Plio-Quaternary Kula volcanic field, west of Usak (Intraplate) and finally we discuss and compare all the above areas with the already studied (d) Quaternary Ecuadorian volcanic arc (host to the Miocene Llurimagua Cu-Mo and Cascabel Cu-Au porphyry deposits) (Subduction). The volcanism of the studied areas displays a wide range of SiO2 spanning from basalts to andesites/dacites and from high K-calc-alkaline to shoshonitic series. Multiphase magmatic sulphides occur in different amounts in all investigated areas and based on textural and compositional differences, they can be classified in different types, which crystallised at different times (early versus late saturation). A decrease in the sulphide Ni/Cu (proxy for mss-monosulphide solid solution/iss-intermediate solid solution) ratio is noted with magmatic evolution. Starting with an early stage, saturating Ni-richer/Cu-poorer sulphides hosted by early crystallising minerals e.g. olivine/pyroxene, leading up to a later stage, producing Cu-richer sulphides hosted by magnetite. The most common sulphide type resulting from an early saturating stage is composed of a Cu-poor/Ni-rich (pyrrhotite/mss) and one/two Cu-rich (cubanite, chalcopyrite/iss) phases making up 84 and 16 area % of the sulphide, respectively. Our results suggest that independently of the magma composition, geodynamic setting and whether or not the system has generated an ore deposit on the surface, sulphide saturation occurred in variable degrees in all studied areas and magmatic systems and is characterised by a similar initial metal content of the magmas. However not all studied areas present all sulphide types and the sulphide composition is dependent on the nature of the host mineral. In particular sulphides, resulting from the late stage, consisting of Cu-rich phases (chalcopyrite ,bornite, digenite/iss) are hosted exclusively by magnetite and are found only in magmatic provinces associated with porphyry Cu (Konya and Ecuador) and porphyry Au (Beydagi) deposits.

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confidence: 56%

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confidence: 99%

Magmatic sulphides in high-K calc-alkaline to shoshonitic and alkaline rocks

Georgatou

Chiaradia

2019

Preprint

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“…Tetra-auricupride has been documented in association with concentrically zoned Alaskan-Uralian-(Aldan)-type complexes at Tulameen*, BC, Canada; Nizhniy Tagil, Urals; and Kondyor*, Aldan Shield, Russia [5][6][7]. It also occurs in layered mafic-ultramafic complexes at Jijal, Pakistan [8]; Yoko-Dovyrenskiy, southern Siberia [9]; Burakovskiy, Karelia, Russia [10]; and Skaergaard, Greenland [11,12]; and in serpentinized ophiolitic rocks on the island of Skyros [13] and the Pindos complex, Greece [14]. It was also found in ore at the Kerr-Addison mine, ON, Canada [15]; in the Itabira district, Minas Gerais, Brazil [16]; the Bleida Far West mine, Morocco [17]; the Sieroszowice mine, Poland [18]; and in association with Cu-Ni sulfide deposits of the Noril'sk complex, Krasnoyarskiy kray, Russia [19,20] and in the alkaline Coldwell gabbro-syenite complex in Ontario, Canada [21].…”

Section: Worldwide Occurrences Of Tetra-auricupridementioning

confidence: 99%

Platiniferous Tetra-Auricupride: A Case Study from the Bolshoy Khailyk Placer Deposit, Western Sayans, Russia

et al. 2019

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Tetra-auricupride, ideally AuCu, represents the only species showing the coexistence of Au with an elevated level of Pt, as in the case of a detrital grain studied structurally for the first time, from an ophiolite-associated placer at Bolshoy Khailyk, western Sayans, Russia. We infer that tetra-auricupride can incorporate as much as ~30 mol. % of a “PtCu” component, apparently without significant modification of the unit cell. The unit-cell parameters of platiniferous tetra-auricupride are: a 2.790(1) Å, c 3.641(4) Å, with c/a = 1.305, which are close to those reported for ordered AuCu(I) in the system Au–Cu, and close also to the cell parameters of tetraferroplatinum (PtFe), which both appear to crystallize in the same space group, P4/mmm. These intermetallic compounds and natural alloys are thus isostructural. The closeness of their structures presumably allows Pt to replace Au atoms so readily. The high extent of Cu + Au enrichment is considered to be a reflection of geochemical evolution and buildup in levels of the incompatible Cu and Au with subordinate Pt in a remaining volume of melt at low levels of fO2 and fS2 in the system.

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“…Scales in counts-per-second. Measured isotopes: 56 Fe, 69 Ga, 75 As, 59 Co, 60 Ni, 109 Ag, 2095 Bi, 182 W.…”

Section: What Is Being Analyzed?mentioning

confidence: 99%

Trace Element Analysis of Minerals in Magmatic-Hydrothermal Ores by Laser Ablation Inductively-Coupled Plasma Mass Spectrometry: Approaches and Opportunities

et al. 2016

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Laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) has rapidly established itself as the method of choice for generation of multi-element datasets for specific minerals, with broad applications in Earth science. Variation in absolute concentrations of different trace elements within common, widely distributed phases, such as pyrite, iron-oxides (magnetite and hematite), and key accessory minerals, such as apatite and titanite, can be particularly valuable for understanding processes of ore formation, and when trace element distributions vary systematically within a mineral system, for a vector approach in mineral exploration. LA-ICP-MS trace element data can assist in element deportment and geometallurgical studies, providing proof of which minerals host key elements of economic relevance, or elements that are deleterious to various metallurgical processes. This contribution reviews recent advances in LA-ICP-MS methodology, reference standards, the application of the method to new mineral matrices, outstanding analytical uncertainties that impact on the quality and usefulness of trace element data, and future applications of the technique. We illustrate how data interpretation is highly dependent on an adequate understanding of prevailing mineral textures, geological history, and in some cases, crystal structure.

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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

Cited by 49 publications

References 78 publications

Magmatic sulphides in high-K calc-alkaline to shoshonitic and alkaline rocks

Magmatic sulphides in high-K calc-alkaline to shoshonitic and alkaline rocks

Platiniferous Tetra-Auricupride: A Case Study from the Bolshoy Khailyk Placer Deposit, Western Sayans, Russia

Trace Element Analysis of Minerals in Magmatic-Hydrothermal Ores by Laser Ablation Inductively-Coupled Plasma Mass Spectrometry: Approaches and Opportunities

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