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Xieyan Song - One of the best experts on this subject based on the ideXlab platform.

  • implications of nano and micrometer size platinum group element minerals in base metal sulfides of the yangliuping ni cu pge sulfide deposit sw china
    Chemical Geology, 2019
    Co-Authors: Qinglin Liang, Xieyan Song, Richard Wirth, Liemeng Chen
    Abstract:

    Abstract The concentrations of platinum-group elements (PGE) and semimetal elements (As, Sb, Se, Te and Bi) in the base metal sulfides from the Yangliuping deposit were determined using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS). Mass balance calculation reveals that the base metal sulfides only contain Cu-(PGE) sulfide deposits. Euhedral shape and similar chemical composition of the nanometer-size PGE-arsenides and sulfarsenides in the base-metal sulfides suggest that they crystallized from the sulfide melt before the crystallization of monosulfide solid solution (MSS) and intermediate solid solution (ISS). It is proposed that the nanometer-size PGE-arsenides and sulfarsenides formed from PGE-As molecular or polymolecular clusters in the sulfide liquid at high temperature. The PGE-As molecular or polymolecular clusters prevent As and PGE from partitioning into the base metal sulfide lattice and tend to form discrete nanometer-size PGE-arsenides and sulfarsenides. Thus, semimetal elements, particularly As, play an important role on behaviour of PGE during solidification of magmatic sulfide liquids.

  • controls on the metal compositions of magmatic sulfide deposits in the emeishan large igneous province sw china
    Chemical Geology, 2008
    Co-Authors: Xieyan Song, Meifu Zhou, Jiafei Xiao
    Abstract:

    Abstract Magmatic sulfide deposits in the Emeishan large igneous province, SW China, have variable chalcophile and siderophile metal contents and can be divided into PGE, Ni–Cu–PGE and Ni–Cu deposits. PGE sulfide deposits include the Jinbaoshan and Zhubu deposits and have ores with very low sulfide contents (~ 1 to 2 vol.%) and very high Pt and Pd (0.3 to 10 ppm) and Ir (0.02 to 0.5 ppm). Typical Ni–Cu–PGE sulfide deposits include the Yangliuping and Qingkuangshan deposits, which contain sulfide ores with more than 10 vol.% sulfides (0.1–6.2 wt.% Ni, 0.03–11 wt.% Cu) and have moderate PGE contents (0.1–5 ppm Pt, 0.01–1.8 ppm Pd, On the 100% sulfide basis, Pt and Pd correlate positively with Ir in the ores from the PGE deposits, whereas they correlate negatively in the Ni–Cu–PGE and Ni–Cu deposits. PGE geochemistry and model calculations indicate that the PGE-rich sulfides were separated from primary basaltic magmas, whereas the Ni–Cu–PGE sulfides were produced from magmas that had experienced minor sulfide removal (about 0.01%), and the Ni–Cu sulfides were separated from magmas that experienced about 0.025% sulfide segregation. Fractionation of monosulfide solid solution resulted in differentiation between IPGE and PPGE in the Ni–Cu–PGE and Ni–Cu deposits.

  • genetic relationships between base metal sulfides and platinum group minerals in the yangliuping ni cu pge sulfide deposit southwestern china
    Canadian Mineralogist, 2004
    Co-Authors: Xieyan Song, Meifu Zhou, Zhimin Cao
    Abstract:

    The Yangliuping Ni‐Cu‐(PGE) sulfide deposit in southwestern China is hosted by a series of mafic-ultramafic sills that intrude Devonian strata. Massive sulfides and disseminated sulfides occur at the base of the sills. Minor massive sulfide veins occur in footwall fractures. The major base-metal sulfides (BMS) are pyrrhotite, pentlandite, and chalcopyrite. The most common PGE-bearing sulfarsenide is a Pd-bearing cobaltite‐gersdorffite solid solution. Other PGM identified include sperrylite, testibiopalladite, and Pd-bearing melonite. All grains of the cobaltite‐gersdorffite solid solution and PGM are enclosed in pyrrhotite and pentlandite. Both the PGM and their host BMS have been partially altered in place by hydrothermal fluids. Electron-microprobe analyses show that pyrrhotite and pentlandite contain up to 0.1‐0.5 wt% Pt. Euhedral grains of cobaltite‐ gersdorffite solid solution ( 600°C based on the phase relations of the system FeAsS‐NiAsS‐CoAsS. Sperrylite and testibiopalladite crystals are up to 50‐80 � m in diameter and are compositionally homogeneous. Some testibiopalladite crystals occur in the contact of two pyrrhotite grains. Monosulfide solid-solution was the first phase to crystallize from a sulfide melt, and it then exsolved to pyrrhotite and pentlandite. Pt and Pd became enriched in the residual sulfide liquid, and crystallized as PGM and Pd-bearing cobaltite‐gersdorffite solid solution at a lower temperature. Minor Pt and Pd in Mss were finally expelled from the structure below 800°C.

Kenneth T Douglas - One of the best experts on this subject based on the ideXlab platform.

Sarah-jane Barnes - One of the best experts on this subject based on the ideXlab platform.

  • the role of black shales as a source of sulfur and semimetals in magmatic nickel copper deposits example from the partridge river intrusion duluth complex minnesota usa
    Ore Geology Reviews, 2017
    Co-Authors: Nadege Samalens, Sarah-jane Barnes, E W Sawyer
    Abstract:

    The basal unit of the Duluth Complex (Minnesota, USA) contains Ni-Cu sulfide deposits. The S in these is thought to be derived from a sulfide-rich black shale unit known as the Bedded Pyrrhotite Unit, a stratigraphic unit within the Virginia Formation host rocks. However, the mechanism of S transfer has not been clearly established. In order to understand how this transfer occurs we have undertaken petrography and whole rock geochemistry of the rocks from the contact aureole and the basal unit. In the contact aureole, the Bedded Pyrrhotite Unit consists of a very fine-grained graphitic shales with thin beds of sulfides consisting of pyrrhotite with minor chalcopyrite (< 1%). The basal unit contains numerous Bedded Pyrrhotite Unit xenoliths surrounded by norites. The Bedded Pyrrhotite Unit xenoliths are partially melted and the sulfide beds are disrupted. Leucosomes are present and these contain blebs of sulfides consisting of pyrrhotite, pentlandite, cubanite and chalcopyrite. In the mafic rocks surrounding the xenoliths small patches of sulfide-bearing leucosome are found. In addition to being rich in S the Bedded Pyrrhotite Unit is rich in As 38 ppm, Sb 4.1 ppm and Bi 0.6 ppm and Te 0.4 ppm and has high δ34S values. The δ34S, As/S, Bi/S and Sb/S decrease with distance from the xenoliths. Similarly, the Ni/S, Cu/S, Se/S and (platinum-group elements)/S ratios are higher in the mafic rocks and increase with distance from the xenoliths. Our model proposes that droplets of sulfide melt derived from the Bedded Pyrrhotite Unit xenoliths were entrained in the anatectic silicate melt of the xenoliths and transferred to the mafic magma. The sulfide droplets equilibrated with the mafic magma. Those close to the xenoliths did not have the opportunity to react with a large quantity of magma, and hence their composition is similar to the sulfides of the Bedded Pyrrhotite Unit, i.e., rich in semimetals and poor in Ni, Cu and PGE. Farther away from the xenoliths, the sulfide droplets could have reacted with more magma, and the composition of these sulfides approach that of sulfides derived mainly from mafic magma.

  • sulfides and sulfarsenides from the rosie nickel prospect duketon greenstone belt western australia
    Economic Geology, 2012
    Co-Authors: Belinda Godel, Sarah-jane Barnes, Stephen Barnes, Ignacio Gonzalezalvarez, Paull Parker, Jamie Day
    Abstract:

    Recent exploration in the Duketon greenstone belt, Yilgarn craton, Western Australia, led to the discovery of a new occurrence of high-grade Ni-PGE (platinum group element) sulfide mineralization associated with komatiite; this is referred to as the Rosie Ni Prospect. The mineralization consists predominantly of disseminated and brecciated semimassive to massive base metal sulfide with 0.5 to 5 cm thick sulfarsenide-bearing lenses. This pilot study focuses on the petrology, mineralogy, and trace element mineral chemistry of sulfides and sulfarsenides, and the mineralogy of minor PGE-rich minerals (sperrylite, melonite, and bismuthotel-lurides) in selected samples representing different parts of the orebody, with a particular emphasis on the sulfarsenide-rich lenses. Our mineral chemistry and mineralogical studies indicate that As-rich phases (either as a melt or as primary minerals) played a critical role in collecting and concentrating PGEs from the komatiitic magma. The concentrations of trace elements within the sulfarsenides and sulfides from the different mineralization types reflect the interaction between the silicate and sulfide liquids. The concentration of PGEs in the As-rich minerals is a function of the volume of sulfide melt with which they have interacted. The smaller the proportion of the sulfarsenide relative to sulfide in the rock is, the higher the PGE concentration in the sulfarsenide will be. In situ Se analysis of the base metal sulfides from the different ore types indicates that Se concentrations in pentlandite and pyrrhotite from sulfarsenide-rich lenses are an order of magnitude higher than those of sulfides found in As-poor samples. This correlation between the Se concentrations in the sulfide minerals and the As concentration in the whole rock indicates that the processes which led to As enrichment at Rosie also contributed to Se enrichment. The particular As-Se enrichment is inferred to have been triggered by the erosion and assimilation of sulfidic sediments enriched in organic matter (now observed as shales and/or black shales) by the komatiitic magma flows, leading to the formation of immiscible S-As-rich melt, where PGEs partition preferentially into the As-rich phases.

  • the timing and formation of platinum group minerals from the creighton ni cu platinum group element sulfide deposit sudbury canada early crystallization of pge rich sulfarsenides
    Economic Geology, 2010
    Co-Authors: Sarah A S Dare, Sarah-jane Barnes, Hazel Margaret Prichard, Peter Charles Fisher
    Abstract:

    Platinum-group elements (PGE) are typically hosted in base metal sulfides and by platinum-group minerals (PGM) in Ni-Cu-PGE sulfide deposits. At Sudbury, it appears that the majority of PGE are hosted in PGM. In order to understand why this is the case we have investigated the origin of PGM from the 402 trough ore-bodies of the Creighton deposit located on the South Range of Sudbury. These predominantly pyrrhotite-rich sulfides, with low (Pt + Pd)/(Os + Ir + Ru + Rh) whole-rock ratios, represent cumulates of monosulfide solid solution (MSS) that crystallized early from the sulfide melt, collected in troughs and embayments at the base of the Sudbury Igneous Complex, and formed small pendants of ore in the footwall country rock. The majority of PGE (Ir, Rh, Pt ± Os, Ru) show a stronger affinity for the sulfarsenide phases than the cocrystallizing sulfide phases which are strongly depleted in these PGE. The precious metal mineralogy is dominated by PGE sulfarsenides (86%) with subordinate sperrylite (PtAs2: 9%), michenerite (PdBiTe: 5%), and electrum (AgAu2: 0.1%). These discrete minerals are predominantly hosted within pyrrhotite and pentlandite except, however, a large proportion of michenerite is hosted either entirely by silicates and/or juxtaposed against silicates. The PGE sulfarsenides are euhedrally zoned with an irarsite (IrAsS) core, an outer layer of hollingworthite (RhAsS), and a PGE-rich Ni cobaltite rim (CoAsS). Rhenium sulfides, some of which are Os bearing, are documented for the first time at Sudbury. Platinum-group minerals may crystallize directly from sulfide melt, form by exsolution during cooling of the base metal sulfides or recrystallize from them during metamorphism. We propose that zoned PGE sulfarsenides and sperrylite crystallized from a sulfide melt at high temperatures (1,200°–900°C) and were subsequently surrounded by MSS cumulates, even by disseminated sulfides, that crystallized from the now Ir, Rh, Pt ± Os, Ru-depleted immiscible sulfide liquid. The base metal sulfides recrystallized with secondary hydrosilicates at a late magmatic and/or hydrothermal stage (<540°C) at which time michenerite formed. The magmatic zoning of the PGE sulfarsenides was preserved during later deformation in shear zones but these PGM were corroded, fractured, and juxtaposed against silicates.

  • the kabanga ni sulfide deposits tanzania ii chalcophile and siderophile element geochemistry
    Mineralium Deposita, 2010
    Co-Authors: Wolfgang Maier, Sarah-jane Barnes
    Abstract:

    The Kabanga deposit constitutes one of the most significant Ni sulfide discoveries of the last two decades (indicated mineral resource 23 Mt of ore at 2.64% Ni, inferred resource 28.5 Mt at 2.7% Ni, November 2008). The sulfides are hosted by predominantly harzburgitic and orthopyroxenitic intrusions that crystallized from magnesian basaltic and picritic magmas. However, compared with other sulfide ores that segregated from such magmas (e.g., Jinchuan, Pechenga, Raglan), most Kabanga sulfides have low Ni (<1–3%), Cu (∼0.1–0.4%), and PGE contents (≪1 ppm), high Ni/Cu (5–15), and low Ni/Co (10–15) and Pd/Ir (2–20). Sulfides with higher metal contents (up to ∼5% Ni, 0.8% Cu, 10 ppm PGE) are found in only one unit from Kabanga North. The observed metal contents are consistent with segregation of magmatic sulfides from fertile to strongly metal-depleted magmas, at intermediate to very low mass ratios of silicate to sulfide liquid (R factors) of approximately 10–400. Sulfide saturation was triggered prior to final emplacement, by assimilation of up to 50% of the total sulfur in the intrusions from sulfide-bearing metasedimentary country rocks. Immiscible sulfide liquid was entrained by the magma and ultimately precipitated in dynamic magma conduits that formed tubular and sill-like mafic–ultramafic bodies characterized by abundant magmatic breccias, highly irregular layering, and frequent compositional reversals. The unusually large degree of crustal contamination and the low R factors render Kabanga an end-member in the spectrum of magmatic Ni sulfide ores.

  • variations in the nature of the platinum group minerals in a cross section through the merensky reef at impala platinum implications for the mode of formation of the reef
    Canadian Mineralogist, 2004
    Co-Authors: Hazel Margaret Prichard, Sarah-jane Barnes, W Maier, Peter Charles Fisher
    Abstract:

    A study of the abundance, size, distribution and composition of platinum-group minerals in samples from a section of the Merensky Reef at Impala Platinum, on the farm Reinkoyalskraal, in the western Bushveld Complex, South Africa, has shown that melanorite, leuconorite and anorthosite contain a PGM assemblage that consists almost exclusively of Pt and Pd bismuthotellurides, predominantly moncheite and merenskyite. In the chromite-rich lithologies, this assemblage of Pt–Pd–Bi telluride PGM is joined by a Pt–Pd–Rh sulfide PGM assemblage of cooperite, braggite and an unnamed Cu–Pt–Rh sulfide, with laurite and rare Sn-bearing PGM. This additional assemblage tends to be Pd-poor. The PGM are rarely enclosed by chromite. All the PGM are predominantly associated with base-metal sulfides, either as euhedral PGM or laths forming an exsolution texture within the base-metal sulfides. Rhodium, present as the unnamed Cu–Pt–Rh sulfide, is associated with pyrrhotite and pentlandite. Throughout this section of the reef, the PGM are commonly located at the edge of base-metal sulfides adjacent to serpentine, chlorite and amphibole that form on the edges of silicate grains. In the chromite-poor samples, Pt–Pd–Bi tellurides and their associated base-metal sulfides are located commonly within silicates, including plagioclase and quartz. The chromite-bearing rocks in this section of the Merensky Reef are enriched in Os, Ir, Ru, Rh and Pt. We test three models for the formation of the PGM: coprecipitation of PGM and chromite, crystallization of PGM from a sulfide liquid, and redistribution of PGE and base metals by hydrous intercumulus fluid. The strong association of PGM with base-metal sulfides suggests that the PGE were collected by an immiscible base-metal sulfide liquid. This liquid crystallized as Mss, with Rh being concentrated in the Mss, and then as Iss. These exsolved to pyrrhotite, pentlandite and chalcopyite and PGM. In the chromite-rich layer, we note a lack of minerals containing Pd in the PGM assemblage. No one model satisfactorily explains the PGM distribution. Rather, the PGM observed are likely to result from late, low-temperature processes superimposed on the magmatic ones.

Seheli Parveen - One of the best experts on this subject based on the ideXlab platform.

Meifu Zhou - One of the best experts on this subject based on the ideXlab platform.

  • controls on the metal compositions of magmatic sulfide deposits in the emeishan large igneous province sw china
    Chemical Geology, 2008
    Co-Authors: Xieyan Song, Meifu Zhou, Jiafei Xiao
    Abstract:

    Abstract Magmatic sulfide deposits in the Emeishan large igneous province, SW China, have variable chalcophile and siderophile metal contents and can be divided into PGE, Ni–Cu–PGE and Ni–Cu deposits. PGE sulfide deposits include the Jinbaoshan and Zhubu deposits and have ores with very low sulfide contents (~ 1 to 2 vol.%) and very high Pt and Pd (0.3 to 10 ppm) and Ir (0.02 to 0.5 ppm). Typical Ni–Cu–PGE sulfide deposits include the Yangliuping and Qingkuangshan deposits, which contain sulfide ores with more than 10 vol.% sulfides (0.1–6.2 wt.% Ni, 0.03–11 wt.% Cu) and have moderate PGE contents (0.1–5 ppm Pt, 0.01–1.8 ppm Pd, On the 100% sulfide basis, Pt and Pd correlate positively with Ir in the ores from the PGE deposits, whereas they correlate negatively in the Ni–Cu–PGE and Ni–Cu deposits. PGE geochemistry and model calculations indicate that the PGE-rich sulfides were separated from primary basaltic magmas, whereas the Ni–Cu–PGE sulfides were produced from magmas that had experienced minor sulfide removal (about 0.01%), and the Ni–Cu sulfides were separated from magmas that experienced about 0.025% sulfide segregation. Fractionation of monosulfide solid solution resulted in differentiation between IPGE and PPGE in the Ni–Cu–PGE and Ni–Cu deposits.

  • genetic relationships between base metal sulfides and platinum group minerals in the yangliuping ni cu pge sulfide deposit southwestern china
    Canadian Mineralogist, 2004
    Co-Authors: Xieyan Song, Meifu Zhou, Zhimin Cao
    Abstract:

    The Yangliuping Ni‐Cu‐(PGE) sulfide deposit in southwestern China is hosted by a series of mafic-ultramafic sills that intrude Devonian strata. Massive sulfides and disseminated sulfides occur at the base of the sills. Minor massive sulfide veins occur in footwall fractures. The major base-metal sulfides (BMS) are pyrrhotite, pentlandite, and chalcopyrite. The most common PGE-bearing sulfarsenide is a Pd-bearing cobaltite‐gersdorffite solid solution. Other PGM identified include sperrylite, testibiopalladite, and Pd-bearing melonite. All grains of the cobaltite‐gersdorffite solid solution and PGM are enclosed in pyrrhotite and pentlandite. Both the PGM and their host BMS have been partially altered in place by hydrothermal fluids. Electron-microprobe analyses show that pyrrhotite and pentlandite contain up to 0.1‐0.5 wt% Pt. Euhedral grains of cobaltite‐ gersdorffite solid solution ( 600°C based on the phase relations of the system FeAsS‐NiAsS‐CoAsS. Sperrylite and testibiopalladite crystals are up to 50‐80 � m in diameter and are compositionally homogeneous. Some testibiopalladite crystals occur in the contact of two pyrrhotite grains. Monosulfide solid-solution was the first phase to crystallize from a sulfide melt, and it then exsolved to pyrrhotite and pentlandite. Pt and Pd became enriched in the residual sulfide liquid, and crystallized as PGM and Pd-bearing cobaltite‐gersdorffite solid solution at a lower temperature. Minor Pt and Pd in Mss were finally expelled from the structure below 800°C.

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