A review of sulfur to selenium ratios in magmatic nickel–copper and platinum-group element deposits

Queffurus, Matthias; Barnes, Sarah‐Jane

doi:10.1016/j.oregeorev.2015.02.019

Cited by 78 publications

(24 citation statements)

References 102 publications

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“…This conclusion is consistent with those made for sulphide occurrences in the south of the Labrador Trough (e.g., Chauval et al 1987;Rohon et al 1993). It is also consistent with S/Se ratios that are widely used to constrain the presence of crustal sulphur in magmatic sulphides (Queffurus and Barnes 2015). This is because crustal sulphides typically possess much higher S/Se values than magmatic sulphide.…”

Section: And the Localsupporting

confidence: 91%

“…However, country rocks are characterised by low S/Se values (< 2,000). Low S/Se values in the gabbroic rocks are consistent with an interaction between sulphide and S-undersaturated fluids (Queffurus and Barnes 2015). Little-to-no change in La/Sm N relative to S/Se values argues against wholesale assimilation of country rock, but can be reconciled with devolatilisation of the pyrite-bearing country rock (e.g., Ripley 1981).…”

Section: And the Localmentioning

confidence: 75%

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Contact-style magmatic sulphide mineralisation in the Labrador Trough, northern Quebec, Canada: implications for regional prospectivity

2020

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The Labrador Trough in northern Quebec is currently the focus of ongoing exploration for magmatic Ni-Cu-platinum group element (PGE) sulphide ores. This geological belt hosts voluminous basaltic sills and lavas of the Montagnais Sill Complex, which are locally emplaced among sulphidic metasedimentary country rocks. The recently discovered Idefix PGE-Cu prospect represents a stack of gabbroic sills that host stratiform patchy disseminated to net-textured sulphides (0.2–0.4 g/t PGE+Au) over a thickness of ∼20 m, for up to 7 km. In addition, globular sulphides occur at the base of the sill, adjacent to the metasedimentary floor rocks. Whole-rock and PGE geochemistry indicates that the sills share a common source and that the extracted magma underwent significant fractionation before emplacement in the upper crust. To develop the PGE-enriched ores, sulphide melt saturation was attained before final emplacement, peaking at R factors of ∼10 000. Globular sulphides entrained along the base of the sill ingested crustally derived arsenic and were ultimately preserved in the advancing chilled margin.

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Section: And the Localsupporting

confidence: 91%

Section: And the Localmentioning

confidence: 75%

Contact-style magmatic sulphide mineralisation in the Labrador Trough, northern Quebec, Canada: implications for regional prospectivity

2020

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“…It should be noted that S loss and low S/Se in sulfides could also be induced by postmagmatic partial oxidation of sulfide minerals, unrelated to S-saturation events (Peck and Keays 1990, Dunn 1997, Queffurus and Barnes 2015. While minor oxidation of sulfides is observed in the olivine gabbros (10-20 %), oxidation is unlikely to explain the significantly lower S/Se ratio of these sulfides in comparison to those in the rest of the sill.…”

Section: Discussionmentioning

confidence: 99%

Distinct sulfur saturation histories within the Palaeogene Magilligan Sill, Northern Ireland: implications for Ni – Cu – platinum group element mineralisation in the North Atlantic Igneous Province

et al. 2019

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The ∼60 m thick Magilligan Sill is part of the British Palaeogene Igneous Province in the North Atlantic. The sill comprises layers of dolerite and olivine gabbro, and it intrudes a thick sequence of Mesozoic mudstones and marls, which are locally baked at the sill margins. Since 2014, the sill has been an exploration target for orthomagmatic Ni – Cu – platinum group element (PGE) sulfide mineralisation analogous to the Noril’sk-Talnakh intrusion in Russia. We present new petrological, geochemical, and S isotope data to assess the prospectivity of the sill and the underlying magmatic plumbing system. Most sulfides in the dolerite portions of the sill are <50 μm in size and comprise only pyrite with PGE abundances below the detection limit. In the olivine gabbros, >150 μm size pentlandite, chalcopyrite, and pyrrhotite grains contain <4 ppm total PGE, 1460 ppm Co, and 88 ppm Ag. Pyrite from the dolerites have δ34S ranging from −10.0‰ to +3.4‰ and olivine gabbro sulfides range from −2.5‰ to −1.1‰, suggesting widespread crustal contamination. The S/Se ratios of sulfides in the dolerites and olivine gabbros range from 3500 to 19 500 and from 1970 to 3710, respectively, indicating that the latter may have come from upstream in the magma plumbing system. The Magilligan Sill records multiple injections of mafic magma into an inflating sill package, each with distinct mechanisms towards S saturation. Whilst the sulfide minerals in the sill do not constitute significant mineralisation themselves, detailed in situ studies highlight a divergence in S saturation histories and suggest that a larger volume of olivine gabbro sulfides at depth may be prospective.

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“…The mantle and crust have quite different values of δ 34 S, δ 18 O, S/Se, 207 Pb/ 204 Pb, 208 Pb/ 204 Pb, 187 Os/ 188 Os, γ Os , ( 87 Sr/ 86 Sr) i , and ε Nd (t), and therefore, they can be effectively used to judge the crustal assimilation and contamination of magma [56,57]. It is generally believed that the metallogenic materials (e.g., S, Pb, Cu, Ni, Co, O, and Se) of magmatic Ni-Cu sulfide deposits are mostly from the mantle, but they change significantly with great variation if contaminated with crustal compositions.…”

Section: Crustal Assimilation and Contaminationmentioning

confidence: 99%

Mineral Chemistry, S-Pb-O Isotopes, and S/Se Ratios of the Niubiziliang Ni-(Cu) Sulfide Deposit in North Qaidam Orogenic Belt, NW China: Constraints on the Parental Magma Composition, Evolution, and Sulfur Saturation Mechanism

Sun

Liu³

et al. 2020

Minerals

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The Niubiziliang Ni-(Cu) deposit is the first magmatic Ni-Cu sulfide deposit in the North Qaidam Orogenic Belt (NQOB), NW China, and plays a significant role in geological evolution, Ni-Cu mineralization, and exploration in the NQOB. Here, we report on the mineral chemistry, S-Pb-O isotopes, and S/Se ratios of the mafic-ultramafic complex, which provide insights on the parental magma, evolution, and sulfur saturation mechanism. The Niubiziliang mafic-ultramafic intrusion contains four ore blocks and about ten Ni-(Cu) ore/mineralization bodies. Olivines in Niubiziliang belong to the species of chrysolite with Fo values of 88~89, and the pyroxenes are mainly orthopyroxene (En = 79~82) and clinopyroxene (En = 44~40). The olivines and some pyroxenes likely crystallized in a magma chamber at a depth of 35.45~36.55 km at a high temperature (1289~1369 °C) and pressure (9.38~9.67 kbar), whereas the Niubiziliang complex formed at a moderate depth (8.13~8.70 km) with a temperature and pressure of 1159~1253 °C and 2.15~2.30 kbar, respectively. The parental magma was considered to be high-Mg picritic basalt with MgO and NiO contents of 14.95~16.58% and 0.053~0.068%, respectively, which indicated high-degree partial melting of the depleted mantle. The mantle-derived primary magma underwent significant fractional crystallization and crustal assimilation and contamination, which was strongly supported by S-Pb-O isotope data and S/Se ratios, resulting in sulfur saturation and sulfide immiscibility in the magma. Crustal assimilation and contamination contributed more to sulfur saturation than fractional crystallization.

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A review of sulfur to selenium ratios in magmatic nickel–copper and platinum-group element deposits

Cited by 78 publications

References 102 publications

Contact-style magmatic sulphide mineralisation in the Labrador Trough, northern Quebec, Canada: implications for regional prospectivity

Contact-style magmatic sulphide mineralisation in the Labrador Trough, northern Quebec, Canada: implications for regional prospectivity

Distinct sulfur saturation histories within the Palaeogene Magilligan Sill, Northern Ireland: implications for Ni – Cu – platinum group element mineralisation in the North Atlantic Igneous Province

Mineral Chemistry, S-Pb-O Isotopes, and S/Se Ratios of the Niubiziliang Ni-(Cu) Sulfide Deposit in North Qaidam Orogenic Belt, NW China: Constraints on the Parental Magma Composition, Evolution, and Sulfur Saturation Mechanism

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