Magnetite Chemistry by LA-ICP-MS Records Sulfide Fractional Crystallization in Massive Nickel-Copper-Platinum Group Element Ores from the Norilsk-Talnakh Mining District (Siberia, Russia): Implications for Trace Element Partitioning into Magnetite

2020 ◽  
Vol 115 (6) ◽  
pp. 1245-1266 ◽  
Author(s):  
Charley J. Duran ◽  
Sarah-Jane Barnes ◽  
Eduardo T. Mansur ◽  
Sarah A.S. Dare ◽  
L. Paul Bédard ◽  
...  
Keyword(s):  
Solid Solution ◽  
Fractional Crystallization ◽  
Platinum Group Element ◽  
Group Element ◽  
Sulfide Liquid ◽  
Mining District ◽  
Monosulfide Solid Solution ◽  
Sulfide Deposits ◽  
Chalcophile Elements ◽  
Platinum Group

Abstract Mineralogical and chemical zonations observed in massive sulfide ores from Ni-Cu-platinum group element (PGE) deposits are commonly ascribed to the fractional crystallization of monosulfide solid solution (MSS) and intermediate solid solution (ISS) from sulfide liquid. Recent studies of classic examples of zoned orebodies at Sudbury and Voisey’s Bay (Canada) demonstrated that the chemistry of magnetite crystallized from sulfide liquid was varying in response to sulfide fractional crystallization. Other classic examples of zoned Ni-Cu-PGE sulfide deposits occur in the Norilsk-Talnakh mining district (Russia), yet magnetite in these orebodies has received little attention. In this contribution, we document the chemistry of magnetite in samples from Norilsk-Talnakh, spanning the classic range of sulfide composition, from Cu poor (MSS) to Cu rich (ISS). Based on textural features and mineral associations, four types of magnetite with distinct chemical composition are identified: (1) MSS magnetite, (2) ISS magnetite, (3) reactional magnetite (at the sulfide-silicate interface), and (4) hydrothermal magnetite (resulting from sulfide-fluid interaction). Compositional variability in lithophile and chalcophile elements records sulfide fractional crystallization across MSS and ISS magnetites and sulfide interaction with silicate minerals (reactional magnetite) and fluids (hydrothermal magnetite). Estimated partition coefficients for magnetite in sulfide systems are unlike those in silicate systems. In sulfide systems, all lithophile elements are compatible and chalcophile elements tend to be incompatible with magnetite, but in silicate systems some lithophile elements are incompatible and chalcophile elements are compatible with magnetite. Finally, comparison with magnetite data from other Ni-Cu-PGE sulfide deposits pinpoints that the nature of parental silicate magma, degree of sulfide evolution, cocrystallizing phases, and alteration conditions influence magnetite composition.

Platinum Group Element Enrichment of Natural Quenched Sulfide Solid Solutions, the Norilsk 1 Deposit, Russia

2020 ◽  
Vol 115 (6) ◽  
pp. 1343-1361
Author(s):  
Valeriya D. Brovchenko ◽  
Sergey F. Sluzhenikin ◽  
Elena V. Kovalchuk ◽  
Sofia V. Kovrigina ◽  
Vera D. Abramova ◽  
...  
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Solid Solutions ◽  
Platinum Group Element ◽  
Group Element ◽  
Temperature Fields ◽  
Chemical Compositions ◽  
Monosulfide Solid Solution ◽  
Icp Ms ◽  
Platinum Group

Abstract The deepest terminations of the Mount Rudnaya subvertical massive sulfide offshoots of the Norilsk 1 orebody are composed of exceptionally fine grained sulfides that are believed to be natural quenched sulfide solid solutions. Copper-rich intermediate solid solution (ISS) and Fe-rich monosulfide solid solution (MSS) form an equigranular and lamellar matrix hosting MSS- and ISS-dominant globules. The nonstoichiometric chemical compositions of the solid solutions plot within their high-temperature fields known from experiments. MSS contains 19 to 35 wt % Ni, 0.09 to 0.45 wt % Co, and up to 0.6 wt % Cu and is heterogeneously enriched in Rh (up to 32 ppm), Ir (up to 0.6 ppm), Pt (up to 65 ppm), and Pd (up to 168 ppm). ISS occurs as the lamellar intergrowths of the chalcopyrite (Ccpss) and cubanite (Cubss) solid solutions, which bear up to 4.74 wt % Ni and 0.2 wt % Co and are heterogeneously enriched in Zn, Ag, and In. The assemblage of platinum group minerals (PGMs) is hosted mostly in the ISS and is dominated by Pt-Fe alloys and minerals of the rustenburgite-atokite series, like the set of PGMs at the Norilsk 1 deposit. Similar Pt-Pd-Sn compounds in the laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) spectra of profiles through MSS and ISS are interpreted to be trapped microinclusions. The pentlandite contains up to 0.13 wt % Pt, up to 4.62 wt % Pd, <0.53 wt % Co, and <0.4 wt % Cu according to electron microprobe analysis. LA-ICP-MS data and mapping show that Pd content in the pentlandite increases toward contacts with ISS and decreases toward contacts with MSS, supporting a reaction origin of pentlandite. The wide variations of the concentrations of major and trace elements in the solid solutions, as well as the coexistence of Pd-poor (a few ppm Pd) and Pd-rich (over 4.62 wt % Pd) pentlandite within a single sample, seem to characterize the different generations of the MSS to MSS-ISS globules, antecrysts, and phenocrysts with the distinct histories of enrichment due to exchange with fractionated Cu-platinum group element-rich residue. The directional distribution of Pd of high-temperature primary magmatic origin is preserved due to rapid quenching of the sulfides from ~650°C.

Genesis of the Jinbaoshan PGE-(Cu)-(Ni) deposit: Distribution of chalcophile elements and platinum-group minerals

2021 ◽  
Vol 59 (6) ◽  
pp. 1511-1542
Author(s):  
Yiguan Lu ◽  
C. Michael Lesher ◽  
Liqiang Yang ◽  
Matthew I. Leybourne ◽  
Wenyan He ◽  
...  
Keyword(s):  
Solid Solution ◽  
Platinum Group Element ◽  
Platinum Group Elements ◽  
Group Element ◽  
Monosulfide Solid Solution ◽  
Platinum Group Minerals ◽  
Pd Alloy ◽  
Platinum Group ◽  
Lower Temperature ◽  
Subduction System

ABSTRACT The Jinbaoshan platinum group element-(Cu)-(Ni) deposit in southwest China is a sulfide-poor magmatic platinum-group element deposit that experienced multiple phases of post-magmatic modification. The sulfide assemblages of most magmatic Ni-Cu-platinum-group element deposits in China and elsewhere in the world are dominated by pentlandite-pyrrhotite-chalcopyrite with lesser magnetite and minor platinum-group minerals. However, Jinbaoshan is characterized by (1) hypogene violarite-pyrite 1-millerite-chalcopyrite and (2) supergene violarite-(polydymite)-pyrite 2-chalcopyrite assemblages. The platinum-group minerals are small (0.5–10 μm diameter) and include moncheite Pt(Te,Bi)2, mertieite-I Pd11(Sb,As)4, the atokite Pd3Sn – rustenburgite Pt3Sn solid solution, irarsite IrAsS, and sperrylite PtAs2 hosted mainly by violarite, silicates (primarily serpentine), and millerite. The platinum-group minerals occur in two sulfide assemblages: (1) mertieite-I-dominant (with irarsite, palladium, and Pd-alloy) in the hypogene assemblage and (2) moncheite-dominant (with irarsite, sperrylite, and atokite) in the supergene assemblage. Palladium and intermediate platinum-group elements (Os, Ir, Ru) are concentrated mainly in violarite, polydymite, and pyrite 2. Platinum is seldom hosted by base metal sulfides and occurs mainly as discrete platinum-group minerals, such as moncheite, sperrylite, and merenskyite. Violarite and polydymite in the Jinbaoshan deposit contain more Pb-Ag than pentlandite and pyrrhotite in the Great Dyke and Lac des Iles deposit. The formation of the sulfide assemblages in Jinbaoshan can be interpreted to have occurred in three stages: (1) a magmatic Fe-Ni-Cu sulfide melt crystallized Fe-Ni monosulfide and Cu-rich intermediate solid solutions, which inverted to a primary pyrrhotite-pentlandite-chalcopyrite-magnetite assemblage; (2) an early-secondary hypogene voilarite-millterite-pyrite 1-chalcopyrite assemblage formed by interaction with a lower-temperature magmatic-hydrothermal deuteric fluid; and (3) a late-secondary supergene violarite-polydymite-pyrite 2-chalcopyrite assemblage formed during weathering. Late-magmatic-hydrothermal fluids enriched the mineralization in Pb-Ag-Cd-Zn, which are incompatible in monosulfide solid solution, added Co-Pt into violarite, and expelled Pd to the margins of hypogene violarite and millerite, which caused Pd depletion in the hypogene violarite and the formation of mertieite-I. Supergene violarite inherited Pd and intermediate platinum-group elements from primary pentlandite. Thus, the unusual sulfide assemblages in the Jinbaoshan platinum-group element-(Cu)-(Ni) deposit results from multiple overprinted post-magmatic processes, but they did not significantly change the chalcophile element contents of the mineralization, which is interpreted to have formed at high magma:sulfide ratios (R factors) through interaction of crustally derived sulfide and a hybrid picritic-ferropicritic magma derived from subduction-metasomatized pyroxenitic mantle during impingement of the Emeishan plume on the Paleo-Tethyan oceanic subduction system.

Genesis of sulfide vein mineralization at the Sakatti Ni-Cu-PGE deposit, Finland

2021 ◽  
Vol 59 (6) ◽  
pp. 1485-1510
Author(s):  
Fabian Fröhlich ◽  
Janne Siikaluoma ◽  
Inga Osbahr ◽  
Jens Gutzmer
Keyword(s):  
Solid Solution ◽  
Base Metal ◽  
Platinum Group Element ◽  
Group Element ◽  
Sulfide Liquid ◽  
Intermediate Solid Solution ◽  
Platinum Group Minerals ◽  
Magmatic Sulfide ◽  
Platinum Group ◽  
Residual Melt

ABSTRACT The Sakatti Ni-Cu-platinum-group element deposit is situated in northern Finland and comprises massive, disseminated, and vein sulfide mineralization. A stockwork is formed by chalcopyrite-rich sulfide veins, which contain exceptionally high platinum-group elements and Au grades. The mineralogy and geochemistry of this stockwork zone ore is documented in this investigation. The results are used to develop the first robust genetic concept and its relationship to massive and disseminated mineralization of the Sakatti deposit. This model is similar to that proposed for many Cu-rich magmatic sulfide ores, most importantly the Cu-rich footwall veins described from the Sudbury Complex in Canada and the Cu-rich ore at Noril'sk-Talnakh in Russia. Detailed petrographic studies using a sample suite from exploration drill core intersecting vein-style mineralization revealed a classic magmatic sulfide assemblage of chalcopyrite ± pyrrhotite, pentlandite, and pyrite. More than 1000 platinum-group mineral grains belonging almost exclusively to the moncheite (PtTe2) – merenskyite (PdTe2) – melonite (NiTe2) solid solution series were identified in the studied samples. Notably, almost two thirds of the platinum-group element-bearing minerals consist of melonite. Some of the platinum-group minerals contain inclusions of Ag-rich gold (AgAu2) and muthmannite (AuAgTe2). Most of the platinum-group minerals occur as inclusions in chalcopyrite, although a few grains are located at base-metal sulfide grain boundaries and in fractures in base-metal sulfides. The whole-rock compositions of the stockwork veins are Cu-rich and are interpreted to represent a fractionated Cu-rich sulfide liquid enriched in Pt, Pd, Au, Ag, As, Bi, Pb, Se, Te, Zn, which separated from a monosulfide solid solution (mss). An intermediate solid solution (iss) solidified from the Cu-rich sulfide liquid, recrystallizing chalcopyrite at <550 °C. Simultaneously, small volumes of intercumulus residual melt contained mainly the precious metals, Bi, and Te due to their incompatibility in iss. Solitary and composite platinum-group minerals as well as Au-minerals crystallized first from the residual melt (<600 °C), followed by a succession of various Bi-, Ag-, and Pb-tellurides (∼540 °C), and finally sphalerite and galena. Melonite crystallized as mostly large, solitary grains exsolved directly from Ni-bearing intermediate solid solution (∼600 °C), shortly after the formation of moncheite and merenskyite from the residual melt. Finally, remobilization of the platinum-group minerals occurred at temperatures of <300 °C, as suggested by the presence of minor amounts of Cl-bearing minerals and ragged grain shapes.

Nano- and Micrometer-Sized PGM in Ni-Cu-Fe Sulfides from an Olivine Megacryst in the Udachnaya Pipe, Yakutia, Russia

2021 ◽  
Vol 59 (6) ◽  
pp. 1755-1773
Author(s):  
José María González-Jiménez ◽  
Irina Tretiakova ◽  
Marco Fiorentini ◽  
Vladimir Malkovets ◽  
Laure Martin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Field Emission ◽  
Platinum Group Element ◽  
Group Element ◽  
Monosulfide Solid Solution ◽  
Mineral Particles ◽  
Transmission Electron ◽  
Sulfide Melt ◽  
Platinum Group

ABSTRACT This paper focuses on a nanoscale study of nano- and micrometer-size Os-rich mineral particles hosted in a Ni-Fe-Cu sulfide globule found in an olivine megacryst from the Udachnaya pipe (Yakutia, Russia). These platinum-group element mineral particles and their host sulfide matrices were investigated using a combination of techniques, including field emission gun electron probe microanalyzer, field emission scanning electron microscopy, and focused ion beam and high-resolution transmission electron microscopy. The sulfide globule is of mantle origin, as it is hosted in primitive olivine (Fo90–93), very likely derived from the crystallization of Ni-Fe-Cu sulfide melt droplets segregated by liquid immiscibility from a basaltic melt in a volume of depleted subcontinental lithospheric mantle. Microscopic observations by means of field emission scanning electron microscopy and single-spot analysis and mapping by field emission gun electron probe microanalyzer reveal that the sulfide globule comprises a core of pyrrhotite with flame-like exsolutions (usually <10 μm thickness) of pentlandite, which is irregularly surrounded by a rim of granular pentlandite and chalcopyrite. Elemental mapping by energy dispersive spectroscopy (acquired using the high-resolution transmission electron microscopy) of the pyrrhotite (+ pentlandite) core reveals that pentlandite exsolution in pyrrhotite is still observable at the nanoscale as fringes of 100 to 500 nm thicknesses. The sulfide matrices of pyrrhotite, pentlandite, and chalcopyrite contain abundant nano- and micrometer-size platinum group element mineral particles. A careful inspection of eight of these platinum group element particles under focused ion beam and high-resolution transmission electron microscopy showed that they are crystalline erlichmanite (OsS2) with well-developed crystal faces that are distinctively oriented relative to their sulfide host matrices. We propose that the core of the Ni-Fe-Cu sulfide globule studied here was derived from a precursor monosulfide solid solution originally crystallized from a sulfide melt at >1100 °C, which later decomposed into pyrrhotite and the pentlandite flame-like exsolutions upon cooling at <600 °C. Once solidified, the solid monosulfide solid solution reacted with non-equilibrium Cu-and Ni-rich sulfide melt(s), giving rise to the granular pentlandite in equilibrium with chalcopyrite now forming the rim of the sulfide globule. Meanwhile, nano- to micron-sized crystals of erlichmanite crystallized directly from or slightly before monosulfide solid solution from the sulfide melt. Thus, Os, and to a lesser extent Ir and Ru, were physically partitioned by preferential uptake via early formation of nanoparticles at high temperature instead of low-temperature exsolution from solid Ni-Fe-Cu sulfides. The new data provided in this paper highlight the necessity of studying platinum group element mineral particles in Ni-Fe-Cu sulfides using analytical techniques that can image nanoscale textural features in order to better understand the mechanisms of platinum group element fractionation in magmatic systems. These processes may play a crucial role in controlling the background geochemical budgets for siderophile and chalcophile elements in a wide range of mantle-derived magmas.

Partition coefficients for Ni, Cu, Pd, Pt, Rh, and Ir between monosulfide solid solution and sulfide liquid and the formation of compositionally zoned Ni – Cu sulfide bodies by fractional crystallization of sulfide liquid

1997 ◽  
Vol 34 (4) ◽  
pp. 366-374 ◽  
Author(s):  
Sarah-Jane Barnes ◽  
E. Makovicky ◽  
M. Makovicky ◽  
J. Rose-Hansen ◽  
S. Karup-Moller
Keyword(s):  
Solid Solution ◽  
Sulfur Content ◽  
Fractional Crystallization ◽  
Copper Sulfide ◽  
Partition Coefficients ◽  
Crystal Fractionation ◽  
Sulfide Liquid ◽  
Monosulfide Solid Solution ◽  
Experimental Systems ◽  
Nickel Copper

Many nickel–copper sulfide orebodies contain Cu- and Fe-rich portions. The Fe-rich ore is generally richer in Os, Ir, Ru, and Rh and poorer in Pt, Pd, and Au than the Cu-rich ore. In komatiite-hosted ores Ni tends to be concentrated in the Cu-rich ore, whereas in tholeiitic ores it tends to be concentrated in the Fe-rich ore. The origin of this zonation could be due to crystal fractionation of Fe-rich monosulfide solid solution from a sulfide liquid. The crystal fractionation would produce an Fe-rich cumulate enriched in Os, Ir, Ru, and Rh and a fractionated liquid enriched in Cu, Pt, Pd, and Au. This model can be tested for zoned orebodies by applying experimentally determined partition coefficients for the metals into monosulfide solid solution. We have compared our experimental results with those of other workers to show that the partition coefficients are strongly influenced by the sulfur content of the system. There is a positive correlation between the partition coefficients and sulfur content of the monosulfide solid solution and between the partition coefficients and the sulfur content of the liquid. In sulfur-saturated and sulfur-over-saturated experimental systems, the metals behave in a manner consistent with the model, that is, Os, Ir, Ru, and Rh are compatible with monosulfide solid solution, Cu, Pd, and Pt are incompatible, and Ni has a partition coefficient close to 1. The use of the experimental partition coefficients is demonstrated in the numerical modelling of a zoned komatiite-related ore (Alexo, Abitibi Greenstone Belt) and a zoned tholeiite-related ore (Oktyabr'sky, Noril'sk region, Siberia). In both cases, the experimental partition coefficients numerically model the composition zones of the actual ores. This supports the model of fractional crystallization of a monosulfide solid solution from a sulfide liquid to form zoned orebodies. Furthermore, it indicates that the experimentally determined partition coefficients are geologically reasonable.

Platinum-group element sulpharsenides and Pd bismuthotellurides in the metamorphosed Ni-Cu deposit at Las Aguilas (Province of San Luis, Argentina)

1997 ◽  
Vol 61 (409) ◽  
pp. 861-877 ◽  
Author(s):  
Fernando Gervilla ◽  
Alejandro Sáncnez-Anguita ◽  
Rogelio D. Acevedo ◽  
Purificación Fenoll Hach-Ali ◽  
Andres Paniagua
Keyword(s):  
Platinum Group Element ◽  
Shear Zones ◽  
Group Element ◽  
Monosulfide Solid Solution ◽  
Crustal Rocks ◽  
Grade Metamorphism ◽  
San Luis ◽  
Sulphide Ore ◽  
High Grade Metamorphism ◽  
Platinum Group

AbstractThe Las Aguilas Ni-Cu-PGE deposit is associated with a sequence of basic-ultrabasic rocks made up of dunite, harzurgite, norite and amphibolite. These igneous (partially metamorphosed) rocks, and their host granulites, gneisses and migmatites of probable Precambrian age, are highly folded. The sulphide ore, consisting of pyrrhotite, pentlandite and chalcopyrite, occurs in the cores of both antiform and synform structures, within dunite, harzburgite and mainly along shear zones in bronzitite, replacing small mylonitic subgrains. The platinum-group mineral assemblage is dominated by Pd bismuthotellurides (Pt-free merenskyite, palladian bismuthian melonite and michenerite), with minor sperrylite, and PGE-sulpharsenides. The latter often occur as single, zoned crystals frequently showing cores of irarsite; outside these are concentric zones of cobaltian hollingworthite, rhodian nickelian cobaltite and Fe-rich nickelian cobaltite.Mineralogical, textural and chemical evidence indicate that the sperrylite and platinum-group element sulpharsenides were formed during a primary magmatic event associated with the fractionation of a basaltic melt, which was contaminated by the assimilation of metamorphic crustal rocks. PGE sulpharsenides crystallized from As-bearing, residual magmatic liquids that collected PGE and segregated after the crystallization of the monosulfide solid solution. During high-grade metamorphism, sulpharsenides were remobilized as solid crystals in the liquated sulfides suffering partial dissolution and fracturing. On the other hand, there is no evidence of a primary concentration of Pd-bismuthotelluride minerals, and their present spatial distribution is only the consequence of their formation under high- to medium-grade metamorphism, down to temperatures of below 500°C. Pd bismuthotellurides crystallize even in fractures of sulpharsenides, attached to the boundaries of highly dissolved sulpharsenide crystals, and intergrown with molybdenite.

Platinum-group element mineralization in an As-rich magmatic sulphide system, Talnotry, southwest Scotland

2004 ◽  
Vol 68 (2) ◽  
pp. 395-411 ◽  
Author(s):  
M. R. Power ◽  
D. Pirrie ◽  
J. Jedwab ◽  
C. J. Stanley
Keyword(s):  
Solid Solution ◽  
Mineral Assemblage ◽  
Platinum Group Element ◽  
Group Element ◽  
Sulphide Mineralization ◽  
Group Mineral ◽  
Intermediate Solid Solution ◽  
Sulphide Liquid ◽  
Mineral Assemblages ◽  
Platinum Group

AbstractArsenic-rich magmatic sulphide mineralization is hosted by a diorite intrusion at Talnotry, southwest Scotland. A relatively abundant and diverse platinum-group mineral assemblage is present and is dominated by sperrylite, irarsite and electrum with subordinate merenskyite, michenerite and froodite. Early euhedral gersdorffite is enriched with respect to Rh, Ir and Pt and in some cases contains exsolved blebs of irarsite or euhedral grains of sperrylite. Sperrylite is also enclosed within silicates and sulphides indicating that it crystallized directly from an As-rich sulphide liquid. Pyrrhotite-chalcopyrite mineral assemblages are consistent with the fractional crystallization of monosulphide solid solution and are overlain by PGE-, Ni- and As-rich mineral assemblages indicative of crystallization from a NiAs liquid. Late-stage, cross-cutting, electrum-bearing chalcopyrite veins are consistent with the crystallization of Cu- and Au-rich intermediate solid solution. The chemistry, mineralogy and lithological relationships of the diorite suggest that it may be an appinite and as such is potentially analogous to the Au-rich lamprophyre dykes present within southwest Scotland.

The effects of post-cumulus alteration on the distribution of chalcophile elements in magmatic sulfide deposits and implications for the formation of low-S-high-PGE zones: The Luanga deposit, Carajás Mineral Province, Brazil

2021 ◽  
Vol 59 (6) ◽  
pp. 1453-1484
Author(s):  
Eduardo Mansur ◽  
Sarah-Jane Barnes ◽  
Cesar F. Ferreira Filho
Keyword(s):  
Base Metal ◽  
Platinum Group Element ◽  
Platinum Group Elements ◽  
Group Element ◽  
Metal Sulfides ◽  
Chalcophile Elements ◽  
Platinum Group Minerals ◽  
Base Metal Sulfides ◽  
Magmatic Sulfide ◽  
Platinum Group

ABSTRACT Most of the World's platinum-group element ore deposits occur as thin stratiform layers within layered intrusions. These layers generally contain disseminated base-metal sulfides or chromite. However, cryptic platinum-group element deposits also occur without chromite or base-metal sulfides in what are known as low-S-high platinum-group element deposits. The origin of these deposits is not clearly understood. The Luanga Complex hosts the largest platinum-group elements resource in South America (i.e., 142 Mt at 1.24 ppm Pt + Pd + Au and 0.11% Ni) and hosts both a platinum-group element deposit containing disseminated base-metal sulfides (style 1) and a low-S-high platinum-group element deposit (style 2). It therefore offers the opportunity to compare the two deposit types in the same overall geological setting and consider how the low-S-high platinum-group element deposit could have formed. The first deposit style is termed the Sulfide zone and consists of a 10–50 meter-thick interval with disseminated base metal sulfides, whereas the second style is named low-S-high-Pt-Pd zone and consists of 2–10 meter-thick discontinuous lenses of 1–5 meter-thick sulfide- and oxide-free harzburgite and orthopyroxenite with discrete platinum-group minerals. Secondary assemblages commonly replace primary igneous minerals to a variable extent throughout the deposit, and thus allow for investigating the effects of post-cumulus alteration on the distribution of a wide range of chalcophile elements in a magmatic sulfide deposit at both whole-rock and mineral scale. This study presents the whole-rock distribution of S, platinum-group elements, and Te, As, Bi, Sb, and Se in both mineralization styles and the concentration of trace elements in base-metal sulfides from the Sulfide zone. The Sulfide zone has Pt/Pd ratios around 0.5 and high concentrations of Te, As, Bi, Sb, and Se, whereas the low-S-high-platinum-group element zone has Pt/Pd ratios greater than 1 and much lower Se, Te, and Bi concentrations, but comparable As and Sb contents. This is reflected in the platinum-group element assemblage, comprising bismuthotellurides in the Sulfide zone and mostly arsenides and antimonides in the low-S, high platinum-group elements zone. Moreover, the base-metal sulfides from the Sulfide zone have anomalously high As contents (50–500 ppm), which suggest that the sulfide liquid segregated from a very As-rich silicate magma, possibly illustrated by an average komatiitic basalt that assimilated a mixture of upper continental crust and black shales. We interpret the low-S-high platinum-group elements zone as a product of S loss from magmatic sulfides during post-cumulus alteration of the Luanga Complex. Selenium, Te, Bi, and Pd were also lost together with S, whereas As and Sb were expelled from base-metal sulfide structures and combined with platinum-group elements to form platinum-group minerals, suggesting they may play a role fixating platinum-group elements during alteration. The remobilization of chalcophile elements from magmatic sulfide deposits located in the Carajás Mineral Province may represent a potential source for hydrothermal deposits found in the region.

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