ORCID Profile
0000-0002-4912-9177
Current Organisations
University of Western Australia
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CSIRO
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Ore Deposit Petrology | Geology | Geochemistry | Inorganic Geochemistry | Plant Biology not elsewhere classified | Palaeontology (incl. Palynology) | Geochronology | Mineralogy and Crystallography | Astronomical and Space Sciences | Carbon Capture Engineering (excl. Sequestration) | Chemical Oceanography | Igneous and Metamorphic Petrology | Geochronology | Earth Sciences not elsewhere classified | Ore Deposit Petrology | Nanotechnology | Geomechanics and Resources Geotechnical Engineering | Resources Engineering and Extractive Metallurgy | Petroleum and Reservoir Engineering | Planetary Science (excl. Extraterrestrial Geology) | Seismology and Seismic Exploration | Biomechanical Engineering | Exploration Geochemistry | Nanoscale Characterisation | Geophysical Fluid Dynamics | Isotope Geochemistry | Soil Biology | Carbon Sequestration Science | Materials Engineering Not Elsewhere Classified | Structural Geology | Nanofabrication, Growth and Self Assembly
ANZSRC Socio-Economic Objective (SEO)
Mineral Exploration not elsewhere classified | Expanding Knowledge in the Earth Sciences | Precious (Noble) Metal Ore Exploration | Oil Shale and Tar Sands Mining and Extraction | Alumina production | Oil and Gas Extraction | Mining and Extraction of Precious (Noble) Metal Ores | Flora, Fauna and Biodiversity at Regional or Larger Scales | Ecosystem Assessment and Management of Coastal and Estuarine Environments | Ecosystem Adaptation to Climate Change | Climate Change Mitigation Strategies | Expanding Knowledge in the Environmental Sciences | Dental Health | Expanding Knowledge in Engineering | Titanium Minerals, Zircon, and Rare Earth Metal Ore (e.g. Monazite) Exploration | Expanding Knowledge in the Biological Sciences |
Related Links
Publications
Platinum group element and nickel sulphide ore tenors of the Mount Keith nickel deposit, Yilgarn Craton, Australia
Publisher: Springer Science and Business Media LLC
Date: 15-05-2012
Morphology and particle size distribution of olivines and sulphides in the Jinchuan Ni-Cu sulphide deposit: Evidence for sulphide percolation in a crystal mush
Publisher: Oxford University Press (OUP)
Date: 14-08-2018
Thermomechanical erosion of ore-hosting embayments beneath komatiite lava channels: Textural evidence from Kambalda, Western Australia
Publisher: Elsevier BV
Date: 11-2017
Ruthenium in chromite as indicator for magmatic sulfide liquid equilibration in mafic-ultramafic systems
Publisher: Elsevier BV
Date: 06-2018
Plume-lithosphere interaction at craton margins throughout Earth history
Publisher: Elsevier BV
Date: 10-2018
Indicator minerals for magmatic sulfide mineralisation
Publisher: Informa UK Limited
Date: 11-11-2019
Geochemistry and tectonic setting of basalts from the Eastern Goldfields Superterrane
Publisher: Informa UK Limited
Date: 07-2012
The range of spinel compositions in terrestrial mafic and ultramafic rocks
Publisher: Oxford University Press (OUP)
Date: 12-2001
Maggie hays Ni deposit: Part 2. nickel mineralization and the spatial distribution of PGE ore-forming signatures in the Maggie hays Ni system, lake Johnston greenstone belt, western Australia
Publisher: Society of Economic Geologists
Date: 08-2012
2.7 Ga plume associated VHMS mineralization in the Eastern Goldfields Superterrane, Yilgarn Craton
Publisher: Elsevier BV
Date: 04-2017
Komatiites of the Wildara-Leonora Belt, Yilgarn Craton, WA: The missing link in the Kalgoorlie Terrane?
Publisher: Elsevier BV
Date: 02-2012
The Mordor Alkaline Igneous Complex, Central Australia: PGE-enriched disseminated sulfide layers in cumulates from a lamprophyric magma
Publisher: Springer Science and Business Media LLC
Date: 16-05-2008
Nickel in olivine as an exploration indicator for magmatic Ni-Cu sulfide deposits: A data review and re-evaluation
Publisher: Mineralogical Society of America
Date: 03-01-2023
DOI: 10.2138/AM-2022-8327
Abstract: Nickel contents of olivine have been widely used as petrogenetic indicators and as fertility indicators for magmatic sulfide potential of mafic-ultramafic intrusions, on the assumption that olivines crystallized from magmas that had equilibrated with sulfide liquid should be relatively depleted in Ni compared with a sulfide-free baseline. This has given rise to a large accumulation of data that is brought together here, along with data on volcanic olivines, to critically evaluate the effectiveness of the approach. We identify multiple sources of variance in Ni content of olivine at a given Fo content, including variability in mantle melt composition due to depth, water content (and possibly source), subsequent fractional crystallization with and without sulfide, recharge and magma mixing, batch equilibration between olivine and sulfide at variable silicate-sulfide ratio (R), and olivine/liquid ratio and subsequent equilibration during trapped liquid crystallization in orthocumulates. Baselines for Ni in olivine in relation to Fo content are somewhat lower in orogenic belt settings relative to intrusions in continental large igneous provinces (LIPs). This is probably related to differences in initial parent magma compositions, with plume magmas generally forming deeper and at higher temperatures. No clear, universal discrimination is evident in Ni in olivine between ore-bearing, weakly mineralized, and barren intrusions, even when tectonic setting is taken into account. However, sulfide-related signals can be identified at the intrusion scale in many cases. Low-R factor and low-tenor sulfides are associated with low-Ni olivines in several ex les, and these cases stand out clearly. Anomalously high-Ni olivines are a feature of some mineralized intrusions, in part due to trapped liquid reaction effects. However, in some cases, this mechanism cannot account for the magnitude of enrichment. In these cases, enrichment may be due to re-entrainment of “primitive” Ni-rich sulfide by a more evolved Fe-rich magma, driving the olivine to become Ni-enriched due to Fe-Ni exchange reaction between sulfide and olivine during transport. An extreme case of this process may account for ultra-Ni enriched olivine at Kevitsa (Finland), but more subtle signals elsewhere could be positive indicators. A lack of clear mineralized/barren distinction in specific groups of related intrusions, e.g., the deposits of NW China or the Kotalahti Belt in Finland, may well be due to “false negatives” where undiscovered mineralization exists in specific intrusions or in their feeder systems, or may also be due to a multiplicity of confounding factors. Wide variability of both Fo and Ni between related intrusions at regional scale may be a useful regional prospectivity indicator, more than an intrusion-scale discriminant, and is certainly informative as a petrogenetic indicator. In general, the use of Ni-olivine as a fertility tool is more likely to generate false negatives than false positives, but both are possible, and the technique should be used as part of a broader weight-of-evidence approach.
Monomineralic anorthosites in layered intrusions are indicators of the magma chamber replenishment by plagioclase-only-saturated melts
Publisher: Springer Science and Business Media LLC
Date: 02-03-2020
DOI: 10.1038/S41598-020-60778-W
Abstract: The formation of some Earth’s monomineralic igneous rocks appears to be prohibited by constraints imposed by liquidus phase-equilibria on evolution of mantle-derived magmas. Yet, these rocks exist as stratiform layers in many mafic-ultramafic intrusions. One conspicuous ex le is monomineralic anorthosites in the Bushveld Complex that occur as stratiform layers up to hundreds of kilometres in length. Such monomineralic anorthosites appear to require parental melts saturated in plagioclase only but where and how to produce these melts remains a contentious issue. Here we argue that they are likely sourced from deep-seated magma reservoirs. In response to pressure reduction, these ascending melts become first superheated and then saturated in plagioclase after stalling and cooling in shallow-level chambers. Adcumulus growth of plagioclase from such melts at the chamber floor results in the formation of monomineralic anorthosites. We propose that stratiform layers of monomineralic anorthosites in layered intrusions are products of the chamber replenishment by melts whose saturation in plagioclase as a single liquidus phase is triggered by their transcrustal ascent towards the Earth’s surface.
Extrusive Origin and Structural Modification of the Komatiitic Mount Keith Ultramafic Unit
Publisher: Society of Economic Geologists
Date: 30-09-2013
Supplemental Material: Role of volatiles in intrusion emplacement and sulfide deposition in the supergiant Norilsk-Talnakh Ni-Cu-PGE ore deposits
Publisher: Geological Society of America
Date: 09-08-2023
DOI: 10.1130/GEOL.S.23915733.V1
Abstract: Geological map (regional and local geology) and stratigraphic column of Paleozoic sedimentary sequence and of the in idual ore-hosting intrusions.
Isotopic investigations of the Nova-Bollinger Ni-Cu-Co deposit in the Fraser Zone, Albany-Fraser Orogen, Western Australia
Publisher: Informa UK Limited
Date: 10-07-2022
Komatiites and Nickel Sulfide Ores of the Black Swan area, Yilgarn Craton, Western Australia. 3. Komatiite geochemistry, and implications for ore forming processes
Publisher: Springer Science and Business Media LLC
Date: 29-10-2004
Investigations of the Howland Reef of the Stillwater Complex, Minneapolis Adit area: stratigraphy, structure and mineralization
Publisher: Society of Economic Geologists
Date: 10-1982
Rapid orthopyroxene growth induced by silica assimilation: constraints from sector-zoned orthopyroxene, olivine oxygen isotopes and trace element variations in the Huangshanxi Ni–Cu deposit, Northwest
Publisher: Springer Science and Business Media LLC
Date: 04-2019
Interspinifex Ni sulfide ore from the coronet shoot, kambalda: characterisation using microbeam XRF mapping and 3D X-ray computed tomography
Publisher: Society of Economic Geologists
Date: 17-06-2016
Automated plotting of geochemical data using the Lotus Symphony package
Publisher: Elsevier BV
Date: 1988
Dynamics of magmatic sulphide droplets during transport in silicate melts and implications for magmatic sulphide ore formation
Publisher: Oxford University Press (OUP)
Date: 12-2015
Role of volatiles in intrusion emplacement and sulfide deposition in the supergiant Norilsk-Talnakh Ni-Cu-PGE ore deposits
Publisher: Geological Society of America
Date: 17-08-2023
DOI: 10.1130/G51359.1
Abstract: The Norilsk-Talnakh orebodies in Siberia are some of the largest ex les on Earth of magmatic Ni−Cu−platinum group element (PGE) deposits, formed by segregation of immiscible sulfide melts from silicate magmas. They show distinctive features attributable to degassing of a magmatic vapor phase during ore formation, including: vesiculation of the host intrusions, widespread intrusion breccias, and extensive hydrofracturing, skarns, and metasomatic replacement in the country rocks. Much of the magmatic sulfide was generated by assimilation of anhydrite and carbonaceous material, leading to injection of a suspension of fine sulfide droplets attached to gas bubbles into propagating tube-like host sills ("chonoliths"). Catastrophic vapor phase exsolution associated with a drop in magma overpressure at the transition from vertical to horizontal magma flow enabled explosive propagation of chonoliths, rapid "harvesting" and gravity deposition of the characteristic coarse sulfide globules that form much of the ore, and extensive magmatic fluid interaction with country rocks.
Native gold enrichment process during growth of chalcopyrite-lined conduits within a modern hydrothermal chimney (Manus Basin, PNG)
Publisher: Mineralogical Society of America
Date: 08-2022
DOI: 10.2138/AM-2021-7866
Abstract: Seafloor hydrothermal chimneys from back-arc basins are important hosts for metals such as Cu, Zn, Pb, Ag, and Au. Although the general growth history of chimneys has been well documented, recent studies have revealed that the fine-scale mineralogy can be highly complex and reflects variable physicochemical conditions of formation. This study utilized a novel combination of scanning electron microscopy (SEM)-based electron backscattered diffraction (EBSD) and synchrotron X-ray fluorescence microscopy (SXFM) to uncover the detailed growth processes of multiple chalcopyrite-lined conduits within a modern chalcopyrite-sphalerite chimney from Manus Basin and to assess the controls on native gold precipitation. On the basis of previous studies, the chimney conduit was thought to develop from an initial sulfate-dominated wall, which was subsequently dissolved and replaced by sphalerite and chalcopyrite during gradual mixing of hydrothermal fluids and seawater. During this process, sphalerite was epitaxially overgrown by chalcopyrite. Accretionary growth of chalcopyrite onto this early formed substrate thickened the chimney walls by bi-directional growth inward and outward from the original tube wall, also enclosing the outgrown pyrite cluster. A group of similar conduits with slightly different mineral assemblages continued to form in the vicinity of the main conduit during the further fluid mixing process. Four types of distinct native gold-sulfide/sulfosalt associations were developed during the varying mixing of hydrothermal fluids and seawater. Previously unobserved chains of gold nanoparticles occur at the boundary of early sphalerite and chalcopyrite, distinct from gold observed in massive sphalerite as identified in other studies. These observations provide baseline data in a well-preserved modern system for studies of enrichment mechanisms of native gold in hydrothermal chimneys. Furthermore, native gold is relatively rarely observed in chalcopyrite-lined conduit walls. Our observations imply that: (1) native gold is closely associated with various sulfides/sulfosalts in chalcopyrite-lined conduit walls rather than limited to the association with tennantite, Bi-rich minerals, and bornite as reported previously and (2) the broad spectrum of gold occurrence in chalcopyrite-line conduits is likely to be determined by the various mixing process between hot hydrothermal fluids with surrounding fluids or seawater. Quantitative modeling of fluid mixing processes is recommended in the future to probe the precise gold deposition stages to efficiently locate gold in modern hydrothermal chimneys.
Trace Element Contents of Mantle-Derived Magmas Through Time
Publisher: Oxford University Press (OUP)
Date: 18-03-2021
DOI: 10.1093/PETROLOGY/EGAB024
Abstract: A large compilation of quality-curated major and trace element data has been assembled to investigate how trace element patterns of mafic and ultramafic magmas have varied with time through particular settings from the Archean to the Phanerozoic, the primary objective being to recognise at what times particular patterns of variation emerge, and how similar these are to baseline data sets representing tectonic settings in the modern Earth. The most informative element combinations involve Nb, Th and the REE, where REE are represented by ‘lambda’ parameters describing slope and shape of patterns. Combinations of the ratios of Th, Nb, La and lambda values from Archean and early Proterozoic basalts and komatiites reveal a distinctive pattern that is common in most well-s led terranes, defining a roughly linear trend in multi-dimensional space from compositions intermediate between modern n-MORB and primitive mantle at one end, towards compositions approximating middle-to-upper continental crust at the other. We ascribe this ‘Variable Th/Nb’ trend in most instances to varying degrees of crustal contamination of magmas with similar compositions to modern oceanic plateau basalts. Komatiites had slightly more depleted sources than basalts, consistent with the hypothesis of derivation from plume tails and heads, respectively. The most significant difference between Precambrian and Phanerozoic plume-derived basalts is that the distinctive OIB-like enriched source component appears to be largely missing from the Archean and Proterozoic geologic record, although isolated ex les of OIB-like trace element characteristics are evident in datasets from even the oldest preserved greenstones. Phanerozoic intra-cratonic LIPs, such as the 260 Ma Emeishan LIP in China, have fundamentally different geochemical characteristics to Archean and Paleoproterozoic assemblages the oldest Proterozoic LIP we have identified that has this type of ‘modern’ signal is the Midcontinent Rift at 1100 Ma. The data are consistent with plume tail sources having changed from being dominantly depleted in the Archean Earth to dominantly enriched in the Phanerozoic Earth, while plume head sources have hardly changed at all. Trace element patterns considered to be diagnostic of subduction are locally present but rare in Archean terranes and become more prevalent through the Proterozoic, although this conclusion is tempered by the large degree of overlap in compositional space between continental arc magmas and continental flood basalts. This overlap reflects the difficulty of distinguishing the effects of supra-subduction metasomatizm and flux melting from those of crustal contamination. Additional factors must also be borne in mind, particularly that trace element partitioning systematics may have been different in all environments in a hotter planet, and large-scale asthenospheric overturns might have been predominant over modern-style plumes in the Archean Earth. Some basaltic suites in particular Archean terranes, notably the western parts of both the Yilgarn and Pilbara cratons in Western Australia and parts of the Superior Craton, have restricted, but locally predominant, suites of basalts with characteristics akin to modern oceanic arcs, suggesting that some process similar to modern subduction was preserved in these particular belts. Ferropicrite magmas with distinctive characteristics typical of modern OIBs and some continental LIPs (notably Emeishan) are rare but locally predominant in some Archean and early Proterozoic terranes, implying that plume sources were beginning to be fertilised by enriched, probably subducted, components as far back as the Mesoarchean. We see no evidence for discontinuous secular changes in mantle-derived magmatism with time that could be ascribed to major mantle reorganisation events. The Archean–Proterozoic transition appears to be entirely gradational from this standpoint. The transition from Archean-style to Phanerozoic-style plume magmatism took place somewhere between 1900 Ma (age of the Circum-Superior komatiitic basalt suites) and 1100 Ma (the age of the Midcontinent Rift LIP).
Sulfide-Olivine Fe-Ni Exchange and the Origin of Anomalously Ni Rich Magmatic Sulfides
Publisher: Society of Economic Geologists
Date: 04-11-2013
Platinum Group Element Geochemistry of Mineralized and Nonmineralized Komatiites and Basalts
Publisher: Society of Economic Geologists
Date: 06-2010
Genesis of the Huangshannan high-Ni tenor magmatic sulfide deposit in the Eastern Tianshan, northwest China: Constraints from PGE geochemistry and Os–S isotopes
Publisher: Elsevier BV
Date: 11-2017
Sulfides and sulfarsenides from the rosie nickel prospect, duketon greenstone belt, Western Australia
Publisher: Society of Economic Geologists
Date: 15-02-2012
Textural development in sulfide-matrix ore breccias in the Aguablanca Ni-Cu deposit, Spain, revealed by X-ray fluorescence microscopy
Publisher: Elsevier BV
Date: 04-2018
The Agnew nickel deposit, Western Australia: part I. Stratigraphy and structure
Publisher: Society of Economic Geologists
Date: 05-1988
Chromite in komatiites: 3D morphologies with implications for crystallization mechanisms
Publisher: Springer Science and Business Media LLC
Date: 04-10-2012
Multidisciplinary study of a complex magmatic system: The Savannah Ni-Cu-Co Camp, Western Australia
Publisher: Elsevier BV
Date: 02-2020
Use and calibration of portable X-Ray fluorescence analysers: Application to lithogeochemical exploration for komatiite-hosted nickel sulphide deposits
Publisher: Geological Society of London
Date: 05-02-2014
Compositions and Ni-Cu-PGE tenors of Nova-Bollinger ores with implications for the origin of Pt anomalies in PGE-poor massive sulfides
Publisher: Society of Economic Geologists, Inc.
Date: 12-2022
DOI: 10.5382/ECONGEO.4894
Abstract: The Nova-Bollinger Ni-Cu-platinum group element (PGE) deposit in the Fraser zone of the Albany-Fraser orogen consists of two main orebodies, Nova and Bollinger, hosted by the same tube-shaped intrusion but having distinctly different Ni tenors of around 6.5 and 4.8 wt %, respectively. Nova is also higher in Pd, but Cu and Pt tenors are similar. Both deposits have very low PGE tenors, with average Pd concentrations of 110 ppb in massive sulfide at Bollinger and 136 ppb at Nova. The Nova and Bollinger orebodies show relatively little internal differentiation overall on deposit scale but show strong differentiation into chalcopyrite-rich and chalcopyrite-poor regions at a meter scale. This differentiation is more prevalent at Nova, where massive sulfide-filled vein arrays are more extensively developed, and in massive ores, particularly veins, than in net-textured ores. Net-textured and disseminated ores have on average Ni and Cu grades and tenors similar to those of massive, semimassive, and breccia ores in the same orebody but a smaller range of variation, largely due to a more limited extent of sulfide liquid fractionation and higher average concentrations of Pt and Pd than adjacent massive ores. Unusually for differentiated magmatic sulfides, there is no systematic positive correlation between Pt, Pd, and Cu. A partial explanation for the lack of a Pd-Cu correlation is that Pd was partitioned into peritectic pentlandite in the middle stages of sulfide liquid solidification. This explanation is not applicable to Pt, as Pt characteristically forms its own phases rather than residing in base metal sulfides. PGE tenors are very low in both orebodies, very similar to those observed in other Ni-Cu-Co sulfide ores in orogenic settings, notably the Savannah and Savannah North orebodies. This depletion is attributed to sulfide retention in the mantle source of the parent magmas rather than to previous fractional extraction of sulfide liquid in staging chambers or feeder networks. The higher Ni and Pd tenors at Nova are attributed to reworking and upgrading of precursor sulfide liquid originally deposited upstream at the Bollinger site. Replicate analyses of multiple jaw-crusher splits returned highly variable Pt and Au assays but much smaller relative errors in the other PGEs. The poor Pt and Au reproducibilities are attributed to nugget effects, explicable by much of the Pt and Au in the s les being present in sparse Pt- and Au-rich grains. This is principally true for Pt in massive rather than disseminated ores, accounting for a strong contrast in the distribution of Pt/Pd ratios between the two ore types. Numerical simulation suggests that Pt is predominantly resident in Pt-rich platinum group minerals with grain diameters of 100 µm or more and that at the low (& ppb) concentrations in these ores, this results in most assays significantly underreporting Pt. This is likely to be true in other low-PGE ores, such that apparent negative Pt anomalies in massive ores may in such cases be attributable to s ling artifacts.
Imaging trace-element zoning in pyroxenes using synchrotron XRF mapping with the Maia detector array: Benefit of low-incident energy
Publisher: Mineralogical Society of America
Date: 2020
DOI: 10.2138/AM-2020-7228
Abstract: Trace-element zoning in igneous phenocrysts and cumulus phases is an informative record of magmatic evolution. The advent of microbeam X-ray fluorescence (XRF) mapping has allowed rapid chemical imaging of s les at thin section to decimeter scale, revealing such zoning patterns. Mapping with synchrotron radiation using multidetector arrays has proved especially effective, allowing entire thin sections to be imaged at micrometer-scale resolution in a matter of hours. The resolution of subtle minor element zoning, particularly in first-row transition metals, is greatly enhanced in synchrotron X-ray fluorescence microscopy (XFM) images by scanning with input beam energy below the FeKα line. In the ex les shown here, from a phenocryst rich trachybasalt from Mt Etna (Italy) and from a Ni-Cu-PGE ore-bearing intrusion at Norilsk (Siberia), the zoning patterns revealed in this way record aspects of the crystallization history that are not readily evident from XFM images collected using higher incident energies and that cannot be obtained at comparable spatial resolutions by any other methods within reasonable scan times. This approach has considerable potential as a geochemical tool for investigating magmatic processes and is also likely to be applicable in a wide variety of other fields.
Introduction to Nickel Sulfide Orebodies and Komatiites of the Black Swan area, Yilgarn Craton, Western Australia
Publisher: Springer Science and Business Media LLC
Date: 29-10-2004
Two distinct origins for Archean greenstone belts
Publisher: Elsevier BV
Date: 04-2018
A Hydrothermal Ni-As-PGE Geochemical Halo Around the Miitel komatiite-Hosted Nickel Sulfide Deposit, Yilgarn Craton, Western Australia
Publisher: Society of Economic Geologists
Date: 23-01-2015
Petrogenetic insights from chromite in ultramafic cumulates of the Xiarihamu intrusion, northern Tibet Plateau, China
Publisher: Mineralogical Society of America
Date: 04-2020
DOI: 10.2138/AM-2020-7222
Abstract: Chromite is one of the earliest crystallized minerals from mafic melts and has been used as an important “petrogenetic indicator.” Its composition may be modified by interaction with intercumulate melt and adjacent minerals. Thus, chromite in mafic-ultramafic rocks contains clues to the geochemical affinity, evolution, and mantle source of its parent magmas. The Devonian Xiarihamu intrusion, located in the East Kunlun Orogenic Belt in the northern Tibet Plateau, China, hosts a very large disseminated Ni-Co sulfide deposit. This study focuses on geochemistry of the chromite enclosed in olivine of ultramafic rocks of the intrusion. Enrichments in Mg and Al in the rim of the chromite indicate only minor effects of alteration on the compositions of the chromite. The chromites enclosed in the olivines with forsterite percentage (Fo) lower than 87 are characterized by large variations in major and trace elements, such as large ranges of Cr·100/(Cr+Al) (Cr# = 15–47), Mg·100/(Mg+Fe2+) (Mg# = 41–65), and Al2O3 (= 26–53 wt%) as well as 380–3100 ppm V, 70–380 ppm Ga, and 1100–16300 ppm Zn. The chromites display positive correlations between Cr/(Cr+Al) and Ti, Mn, V, Ga, and Sc, inconsistent with fractional crystallization but indicative of an interaction between the chromites, intercumulate melts and hosting minerals. In contrast, chromites hosted in olivine with Fo & 87 in harzburgite have small variations in Cr# (ranging from 37 to 41), Mg# (48 to 51), and Al2O3 (30 to 35 wt%) as well as restricted variation in trace elements, indicating relatively weak interaction with trapped liquid and adjacent phases these compositions are close to those of the most primitive, earliest crystallized chromites. The most primitive chromite has similarities with chromite in mid-ocean ridge basalt (MORB) in TiO2 and Al2O3 contents (0.19–0.32 and 27.9–36.3 wt%, respectively) and depletion of Sc and enrichment of Ga and Zn relative to MORB chromite. The geochemistry of the chromite indicates a partial melting of the asthenospheric mantle that was modified by melts derived from the subduction slab at garnet-stable pressures.
Droplets and bubbles: solidification of sulphide-rich vapour-saturated orthocumulates in the Norilsk-Talnakh Ni-Cu-PGE ore-bearing intrusions
Publisher: Oxford University Press (OUP)
Date: 19-12-2019
Global Variability in the Platinum-group Element Contents of Komatiites
Publisher: Oxford University Press (OUP)
Date: 21-12-2011
Textural development in sulfide-matrix ore breccias in the Voisey's Bay Ni-Cu-Co deposit, Labrador, Canada
Publisher: Elsevier BV
Date: 11-2016
The distribution of chromium among orthopyroxene, spinel and silicate liquid at atmospheric pressure
Publisher: Elsevier BV
Date: 09-1986
The structure of and origin of nodular chromite from the Troodos ophiolite, Cyprus, revealed using high-resolution X-ray computed tomography and electron backscatter diffraction
Publisher: Elsevier BV
Date: 03-2015
Ruthenium variation in chromite from komatiites and komatiitic basalts-a potential mineralogical indicator for nickel sulfide mineralization
Publisher: Society of Economic Geologists
Date: 21-02-2013
Diversity of Net-Textured Sulfides in Magmatic Sulfide Deposits: Insights from the Eagle’s Nest Ni-Cu-(Platinum Group Element) Deposit, McFaulds Lake Greenstone Belt, Superior Province, Canada
Publisher: Society of Economic Geologists, Inc.
Date: 12-2022
DOI: 10.5382/ECONGEO.4924
Abstract: The Eagle’s Nest Ni-Cu-(platinum group element PGE) deposit occurs within the 2.73 Ga Esker intrusive complex of the Ring of Fire intrusive suite in the McFaulds Lake greenstone belt of northern Ontario. Mineralization occurs along the northern margin of a formerly ~500-m-high, ~85-m-thick, & ,500-m-long subvertical structurally rotated blade-shaped dike composed of harzburgite, lherzolite, and wehrlite. Three sulfide textural facies are present (percentage as proportion of total mineralization): (1) disseminated (~5%), (2) net texture (~80%), and (3) semimassive to massive (~15%). Five subfacies of net texture have been identified: (1) bimodal olivine-bearing leopard net texture (~50%), (2) inclusion net texture (~5%), (3) orthopyroxene-bearing pinto net texture (& %), (4) localized zones of disrupted net texture (~30%) containing 3- to 5-cm-thick zones of barren amoeboid crosscutting pyroxenite, and (5) fine-grained patchy net texture (~15%). All textural facies are characterized by typical magmatic pyrrhotite-pentlandite-chalcopyrite-(platinum group mineral) assemblages. Massive sulfides are localized in two embayments along the basal contact separated by a topographic high, grading upward to rare semimassive, laterally more continuous net-textured, and disseminated sulfides, with gradational contacts between all textures except massive. Similar mean ore tenors of different sulfide textural facies (Ni100 ~7.5, Cu100 ~4.8), suggest that the majority of the mineralization formed from similar magma compositions at similar magma/sulfide ratios, but the presence of different inclusion populations (peridotite, gabbro, chromitite) and the presence of disrupted net texture indicates that the olivine, inclusions, and sulfide melts accumulated from multiple pulses in a dynamic system. The smaller, blade-shaped, sulfide-rich, chromite-poor Eagle’s Nest body does not appear to be the feeder to the overlying larger, oblate, sulfide-poor, chromite-rich Double Eagle body. This highlights the need to understand the fluid dynamics of entire plumbing systems when exploring for these deposit types and the significance of smaller, more dynamic magmatic conduits as environments favorable for Ni-Cu-(PGE) mineralization.
Petrogenesis of thick, high-grade PGE mineralisation in the Flatreef, northern Bushveld Complex
Publisher: Springer Science and Business Media LLC
Date: 27-01-2023
DOI: 10.1007/S00126-022-01156-6
Abstract: The Flatreef of the northern limb of the Bushveld Complex is a world-class platinum-group element (PGE) deposit representing the down-dip extension of the Platreef. Exploration drilling in the central portion of the project area intersected a particularly thick PGE-mineralised portion of the Flatreef exposed in drill core TMT006 and its two deflections, containing 4.5 ppm PGE (Pt + Pd + Rh + Au) over 90 m and ~ 3.7 ppm PGE over 150 m. Data obtained using whole rock geochemical analysis, field emission scanning electron microscopy, micro X-ray fluorescence and X-ray computed tomography indicate that the PGE are hosted by, or are spatially closely associated with, disseminated sulfides that occur interstitial to the cumulus silicate minerals. PGE grades show a broad, albeit irregular trend of progressive downward decrease, whereas most metal ratios (Cu/Ni, Pt/Rh, Cu/Pd and, to a lesser degree, Pt/Pd) remain broadly constant throughout the 90 m main ore zone. These features are interpreted to reflect two stages of ore formation: (i) hydrodynamic concentration of sulfidic ultramafic crystal mushes and (ii) localised downward percolation of sulfide melt in response to fluidisation of the cumulate mush caused by infiltration of ascending magmatic or crustal fluids. The model is consistent with the close spatial association of the sulfides with interstitial plagioclase as well as accessory phlogopite, quartz, apatite and rutile, whereas cumulus orthopyroxene is largely free of sulfide.
Progressive mixing of meteoritic veneer into the early Earth's deep mantle
Publisher: Springer Science and Business Media LLC
Date: 07-2009
DOI: 10.1038/NATURE08205
The use of An-content of interstitial plagioclase for testing slurry models for the origin of Bushveld massive chromitites
Publisher: Elsevier BV
Date: 12-2023
Petrogenesis and Ni-Cu sulphide potential of mafic-ultramafic rocks in the Mesoproterozoic Fraser Zone within the Albany-Fraser Orogen, Western Australia
Publisher: Elsevier BV
Date: 08-2016
Fred’s Flow (Canada) and Murphy Well (Australia): thick komatiitic lava flows with contrasting compositions, emplacement mechanisms and water contents
Publisher: Springer Science and Business Media LLC
Date: 18-11-2014
The critical role of magma degassing in sulphide melt mobility and metal enrichment
Publisher: Springer Science and Business Media LLC
Date: 29-04-2022
DOI: 10.1038/S41467-022-30107-Y
Abstract: Much of the world’s supply of battery metals and platinum group elements (PGE) comes from sulphide ore bodies formed in ancient sub-volcanic magma plumbing systems. Research on magmatic sulphide ore genesis mainly focuses on sulphide melt-silicate melt equilibria. However, over the past few years, increasing evidence of the role of volatiles in magmatic sulphide ore systems has come to light. High temperature-high pressure experiments presented here reveal how the association between sulphide melt and a fluid phase may facilitate the coalescence of sulphide droplets and upgrade the metal content of the sulphide melt. We propose that the occurrence of a fluid phase in the magma can favour both accumulation and metal enrichment of a sulphide melt segregated from this magma, independent of the process producing the fluid phase. Here we show how sulphide-fluid associations preserved in the world-class Noril’sk-Talnakh ore deposits, in Polar Siberia, record the processes demonstrated experimentally.
Distributions of Platinum Group Elements and Re-Os Isotope Systematics in Chromite from the Coobina Chromitite Deposit in Western Australia: Implications for Chromite as a Sulfide Mineralization Indicator
Publisher: Mineralogical Association of Canada
Date: 11-2022
Abstract: The abundance of Ru in chromite has been suggested as an indicator of sulfide liquid saturation in komatiites. The komatiite magma-derived Archean Coobina intrusion is known to be barren in terms of sulfide mineralization. Therefore, the Coobina intrusion can serve as a useful case study to test the applicability of Ru abundance in chromite as a potential indicator for sulfide mineralization, as well as for better understanding the PGE-chromite association in general. The Coobina intrusion is a highly deformed layered intrusion interpreted to be a flared dike. It contains multiple massive chromitite seams that have been recently mined for metallurgical-grade chromite. In this study, 18 s les from chromitite seams throughout this intrusion are investigated for their whole-rock platinum group element (PGE) contents, which are compared to their chromite mineral chemistry (including PGE content), the platinum group mineral (PGM) mineralogy, and Re-Os isotope systematics. Each s le has a similar chromite major and minor element chemistry, but a unique trace element signature, even within the same seam. In general, there are higher concentrations of Ru (& ppb) within chromite in the southeast (toward the feeder dike) and lower concentrations (& ppb Ru) in the northwest. At a s le scale, Ru in the whole rock and Ru in solid solution in the chromite are inversely correlated, while Ir shows a positive correlation between the whole rock and chromite mineral chemistry, indicating differing partitioning behaviors within the iridium-group PGE (IPGE = Os, Ir, Ru). The inverse correlation between Ru in solid solution within chromite and Ru in whole-rock chromitite suggests that, for seams with high Ru in whole rock, Ru is occurring within separate PGM phases. This is supported by the observation that the s les with high whole-rock Ru also have a high number of visible metal alloy and/or PGM inclusions. Although these inclusions are not necessarily Ru-rich phases, their presence suggests that there is a preference for these s les to form nuggets, which may restrict Ru partitioning into the chromite crystal structure. We suggest that the low Ru values in the Coobina chromite are a result of transient sulfide saturation. The Re-Os isotopic composition of the Coobina chromitite is chondritic [γ187Os(3.189 Ga) = −0.63 ± 0.21] and is consistent with derivation of the Coobina parental magma from the convecting upper mantle source, providing evidence for the mantle origin of the Coobina PGE inventory. If using chromite as a detrital indicator mineral for magmatic sulfide exploration, it must be kept in mind that transient sulfide saturation within chromitite seams may give a false positive signature.
3D textural evidence for the formation of ultra-high tenor precious metal bearing sulphide microdroplets in offset reefs: An extreme example from the Platinova Reef, Skaergaard Intrusion, Greenland
Publisher: Elsevier BV
Date: 07-2016
Multivariate Geochemical Tectonic Discrimination: Practical Approaches, Limitations and Opportunities
Publisher: Informa UK Limited
Date: 11-11-2019
Evolution of a -2.7 Ga large igneous province: A volcanological, geochemical and geochronological study of the Agnew Greenstone Belt, and new regional correlations for the Kalgoorlie Terrane (Yilgarn Craton, Western Australia)
Publisher: Elsevier BV
Date: 11-2015
Resolution of geochemical and lithostratigraphic complexity: a workflow for application of portable X-ray fluorescence to mineral exploration
Publisher: Geological Society of London
Date: 05-02-2014
Time-space evolution of an Archean craton: A Hf-isotope window into continent formation
Publisher: Elsevier BV
Date: 09-2019
SULFUR LIBERATION FROM COUNTRY ROCKS AND INCORPORATION IN MAFIC MAGMAS
Publisher: Society of Economic Geologists
Date: 15-04-2015
Interspinifex Ni sulfide ore from Victor South-McLeay, Kambalda, Western Australia
Publisher: Springer Science and Business Media LLC
Date: 06-05-2021
DOI: 10.1007/S00126-020-00982-W
Abstract: Spinifex-textured olivine plates hosted in sulfides are usually named “interspinifex ore” in komatiite-hosted sulfide deposits. This ore type is rare but provides important genetic information on sulfide deposits, komatiite volcanology and thermomechanical erosion processes. Occurrences in Victor South-McLeay and Moran South (Kambalda, Western Australia) differ significantly from previously reported occurrences in their stratigraphic location, position within the ore profile and textural appearance. Thus, their formation process has to be reconsidered. Interspinifex ore reported here is situated in the lower portion of the basal lava flow between massive and net-textured sulfides in the centre of the embayment and between massive sulfides and older basalt in a “pinchout” where the sulfides melted sideways into older basalt on the embayment edge. Interspinifex ore is composed of up to 10-cm-long aggregates of parallel plates in the upper portion of massive sulfides and is overlain by barren komatiite. The texture does not allow for a classic single explanation. Thus, two possible formation mechanisms are envisaged: (1) A younger komatiite melt intrudes into its own olivine and sulfide liquid cumulate pile, while the sulfides are still liquid. The injection on top of the sulfides causes the formation of an emulsion, from which the spinifex forms due to the temperature gradient between the melts. (2) Interspinifex ore is a relic of an early komatiite flow formed in a series of successive pulses of komatiite and sulfide liquid. The spinifex of the komatiite is invaded by a younger batch of sulfide liquid replacing interstitial silicate melt.
Chromite in komatiites, II. Modification during greenschist to mid-amphibolite facies metamorphism
Publisher: Oxford University Press (OUP)
Date: 03-2000
New insights on chimney growth model and native gold enrichment in modern seafloor hydrothermal chimneys
Publisher: Informa UK Limited
Date: 11-11-2019
Chrome Spinels and Mg-ilmenites from the Noril'sk 1 and Talnakh intrusions and other mafic rocks of the Siberian flood basalt province
Publisher: Society of Economic Geologists
Date: 12-2000
DOI: 10.2113/95.8.1701
Evidence of lateral thermomechanical erosion of basalt by Fe-Ni-Cu sulfide melt at Kambalda, Western Australia
Publisher: Geological Society of America
Date: 20-10-2016
DOI: 10.1130/G37977.1
The Agnew Nickel Deposit, Western Australia: part II. Sulfide geochemistry, with emphasis on the platinum-group elements
Publisher: Society of Economic Geologists
Date: 05-1988
Primary cumulus platinum minerals in the Monts de Cristal Complex, Gabon: magmatic microenvironments inferred from high-definition X-ray fluorescence microscopy
Publisher: Springer Science and Business Media LLC
Date: 25-02-2016
Coupled Li-P zoning and trace elements of olivine from magmatic Ni-Cu deposits: Implications for postcumulus re-equilibration in olivine
Publisher: Oxford University Press (OUP)
Date: 03-2022
DOI: 10.1093/PETROLOGY/EGAC018
Abstract: Olivine is an important mineral in mafic–ultramafic rocks and records various crustal and mantle processes in basaltic magma. Generally, phosphorus (P) is immobile in olivine and its zoning tends to record magmatic processes. In contrast, lithium (Li) is one of the most mobile elements in olivine and tends to be re-distributed by postcumulus to hydrothermal processes. This study reports coupled Li-P oscillatory and sector zoning in cumulus olivine (Fo & 80 mol%) from magmatic Ni-Cu deposits in northwest China. The close to 1:1 relationship between Li + Na cation and P cation in olivine suggests P substitutes for slowly diffusing Si at the tetrahedral site and Li (Na) substitutes for Mg at the octahedral metal site. The preservation of such coupled Li-P zoning suggests that the charge-balanced–controlled substitution of Li+P5+ for Mg2+Si4+, producing a member of the Li(Fe)PO4 structure, may cause sluggish Li diffusion in olivine. The Li-P zoning is uncorrelated to other elements (Fe, Mg, Cr, Al, Ca, Ti, V, Ni, Zn, Mn, Co, and Sc). The Ca abundances in cumulus olivine are significantly depleted relative to those in volcanic olivine and modeled for olivine using the rhyolite–MELTS program, whereas the Mg, Fe, Mn, Zn, Ni, and Co contents show no signs of depletion. The Cr and Al contents in high Fo olivine are lower than those in volcanic olivine with a similar Fo value. The depletions in Ca, Cr, and Al (both alent and trivalent cations) have been attributed to post-crystallization re-equilibration processes. We suggest that the selective Ca-Cr depletion in olivine resulted from re-equilibration between olivine and clinopyroxene–orthopyroxene–spinel–melts at the postcumulus stage, whereas the Al content variation in olivine is likely controlled by olivine–spinel (pyroxene) re-equilibration. Olivine fractionation modeling results reveal that Co content in both olivine and sulfides changes slightly during evolution, whereas the olivine Ni/Co ratio decreases dramatically from 30 (at Fo90) to 4 (Fo80). These are consistent with the variation of Ni and Co contents in olivine from sulfide-barren rocks but cannot explain the strong positive Ni-Co correlation observed in olivine from the sulfide-bearing rocks. The considerable increase in the Ni/Co ratio in olivine coexisting with the high Ni tenor sulfide compared with the slight increase of the Ni/Co ratio in olivine coexisting with moderate-low Ni tenor sulfide strongly suggests that the Ni and Co contents and Ni/Co ratio in olivine from the mineralized rocks were the results of olivine–sulfide interaction. The olivine Fe/Zn and Mn/Zn ratios show little difference between sulfide-barren and sulfide-rich rocks, but these ratios decrease considerably with the decreasing Fo values. Overall, the study suggests that elements (Ca, Cr, Al, Mg, Fe, Ni, Co, Zn, etc.) diffuse faster than P have been re-distributed in cumulus olivine by re-equilibration processes, modifying the elemental content and inter-element ratios in olivine. The characteristics of the crystallization, particularly the source recorded in cumulus olivine, may be obscured and overprinted by postcumulus processes.
Maggie hays Ni deposit: Part 1. stratigraphic controls on the style of komatiite emplacement in the 2.9 Ga lake Johnston greenstone belt, Yilgarn Craton, Western Australia
Publisher: Society of Economic Geologists
Date: 08-2012
Platinum ore in three dimensions: Insights from high-resolution X-ray computed tomography
Publisher: Geological Society of America
Date: 12-2010
DOI: 10.1130/G31265.1
Spatial association between platinum minerals and magmatic sulfides imaged with the Maia Mapper and implications for the origin of the chromite-sulfide-PGE association
Publisher: Mineralogical Association of Canada
Date: 27-05-2021
Abstract: The spatial association between Pt minerals, magmatic sulfides, and chromite has been investigated using microbeam X-ray fluorescence (XRF) element mapping and the Maia Mapper. This lab-based instrument combines the Maia parallel energy dispersive (ESD) detector array technology with a focused X-ray beam generated from a liquid metal source. It proves to be a powerful technique for imaging Pt distribution at low-ppm levels on minimally prepared cut rock surfaces over areas of tens to hundreds of square centimeters, an ideal scale for investigating these relationships. Images of a selection of s les from the Bushveld Complex and from the Norilsk-Talnakh ore deposits (Siberia) show strikingly close association of Pt hotspots, equated with the presence of Pt-rich mineral grains, with magmatic sulfide blebs in all cases, except for a taxitic low-S ore s le from Norilsk. In all of the Bushveld s les, at least 75% of Pt hotspots (by number) occur at or within a few hundred microns of the outer edges of sulfide blebs. In s les from the leader seams of the UG2 chromitite, sulfides and platinum hotspots are also very closely associated with the chromite seams and are almost completely absent from the intervening pyroxenite. In the Merensky Reef, the area ratio of Pt hotspots to sulfides is markedly higher in the chromite stringers than in the silicate-dominated lithologies over a few centimeters either side. We take these observations as confirmation that sulfide liquid is indeed the prime collector for Pt and, by inference, for the other platinum group elements (PGEs) in all these settings. We further propose a mechanism for the sulfide-PGE-chromite association in terms of in situ heterogeneous nucleation of all these phases coupled with transient sulfide saturation during chromite growth and subsequent sulfide loss by partial re-dissolution. In the case of the amygdular Norilsk taxite, the textural relationship and high PGE/S ratio is explained by extensive loss of S to an escaping aqueous vapor phase.
A mechanism for chromite growth in ophiolite complexes: evidence from 3D high-resolution X-ray computed tomography images of chromite grains in Harold’s Grave chromitite in the Shetland ophiolite
Publisher: Mineralogical Society
Date: 28-02-2018
DOI: 10.1180/MINMAG.2017.081.018
Abstract: A fundamental difference exists between the textures of chromite crystals in chromitites in layered complexes and ophiolites. Those in layered complexes generally have euhedral octahedral shapes except where sintered, whereas those in ophiolites generally have rounded shapes accompanied commonly by nodular and more rarely dendritic chromite. Here we describe another texture characteristic of ophiolitic chromitite. The analysis of high-resolution X-ray computed tomography images of chromitite from Harold's Grave in the Shetland ophiolite has revealed 3D hopper structures on chromite grains. In 2D, these hopper structures appear at the surface of the chromite grain as stepped inward facing edges. A study of chromitites in 2D from ten ophiolite complexes has shown that all commonly contain chromite grains displaying these stepped edges. They occur mainly in protected enclaves surrounded by chromite grains that otherwise have rounded edges. The hopper crystals and the often associated clusters of inclusions represent periods of chromite crystal growth in a chromite supersaturated magma due to the presence of a more supercooled and more volatile-rich magma than that present in most layered complexes. Subsequent exposure of chromite crystals to chromite-undersaturated magma caused corrosion, resulting in the characteristic rounded shape of the ophiolitic chromite grains.
Evidence for dyke-parallel shear during syn-intrusion fracturing
Publisher: Elsevier BV
Date: 02-2019
Nova-Bollinger Ni-Cu sulfide ore deposits, Fraser Zone, Western Australia: Petrology of the host intrusions sulfide-silicate textures and emplacement mechanisms of the ores
Publisher: Informa UK Limited
Date: 11-11-2019
Komatiites and nickel sulfide ores of the Black Swan area, Yilgarn Craton, Western Australia. 4. Platinum Group Element distribution in the ores, and genetic implications
Publisher: Springer Science and Business Media LLC
Date: 29-10-2004
Sulfide emplacement and migration in the nova-bollinger Ni-Cu-Co deposit, Albany-Fraser Orogen, Western Australia
Publisher: Society of Economic Geologists
Date: 24-08-2020
DOI: 10.5382/ECONGEO.4758
Abstract: The Nova-Bollinger Ni-Cu sulfide deposit is associated with a small chonolith (tube-shaped) intrusion emplaced at lower crustal depths into granulite facies migmatite gneisses. The deposit comprises disseminated and net-textured ores within the intrusions and a high proportion of massive, semimassive, and breccia exocontact ores within the underlying country rocks. Internally disposed endocontact ores show typical magmatic textures including conventional net texture, leopard net texture characterized by the presence of centimeter-sized clots of olivine and intercumulus phases, and globular ores. Some of the globular ores show an association of sulfide blebs with clinopyroxene-carbonate intergrowths that may represent infilling of original CO2-rich vapor bubbles. The exocontact ores have an assemblage of textures indicative of emplacement into hot, soft country rocks at a large-scale melting-infiltration front. Characteristic features range from hard-walled extensional vein arrays to complex infiltrations of disseminated sulfide within chaotically folded paragneiss. Sulfide infiltration was accompanied by partial melting of the country rock, producing felsic leucosomes, some of them strongly enriched in garnet, mainly occupying vein walls and interpreted as the result of counterflow of displaced silicate partial melt. Coarse-grained pentlandite-chalcopyrite-pyrrhotite loop textures are characteristic of all ore types, down to the scale of the infiltrating sulfides within the gneisses, and are regarded as diagnostically magmatic textures generated by sulfide liquid fractionation and growth of high-temperature pentlandite by peritectic reaction between fractionated sulfide melt and early crystallized monosulfide solid solution. The highly distinctive features of the Nova-Bollinger ores are a consequence of their emplacement in the mid to lower crust under peak granulite facies conditions. Under these unusual conditions the timescales for cooling between the silicate solidus and sulfide solidus temperatures were of the order of millions of years, being controlled by the temperature-time path for the exhumation of the orogen as a whole. Sulfides solidified over a time period three orders of magnitude greater than the thousand-year timescale for the solidification of the host silicate magmas. Furthermore, timescales for deformation matched those for cooling and solidification, allowing the country rocks to undergo deformation during ore emplacement. Fluctuating strain rates during and after initial emplacement of the carrier magmas into the host intrusion caused episodes of brittle extension, allowing unusually efficient penetration of partially molten sulfide into heterogeneous, partially molten silicate country rock, resulting in an unusually extensive thermomechanical aureole compared with other mafic intrusion-hosted nickel systems globally.
The association between Ni-Cu-PGE sulfide and Ni-Co lateritic ores and volcanic facies within the komatiites of the 2.7 Ga East Yilgarn Craton Large Igneous Province, Western Australia
Publisher: Elsevier BV
Date: 2020
Sulfide ore formation of the Kalatongke Ni-Cu deposit as illustrated by sulfide textures
Publisher: Society of Economic Geologists, Inc.
Date: 12-2022
DOI: 10.5382/ECONGEO.4914
Abstract: The Kalatongke magmatic Ni-Cu deposit features high Ni-Cu grades compared with other Ni-Cu deposits in the Central Asian orogenic belt. The sulfides, mainly hosted by olivine norite and gabbronorite, are characterized by high Cu/Ni ratios. There is wide variety of textural relationships in the mineralized rocks, including globular, sulfide matrix, emulsion, disseminated, net-textured, and semimassive to massive textures. Quantitative textural measurements reveal that more than 65 vol % of the total sulfide volume in disseminated ore (defined as containing 4–10 vol % sulfide) and more than 90 vol % of the total sulfide volume in net-textured ore (typically 16 vol % sulfide) are hosted in few interconnected networks with equivalent sphere diameters (ESDs) larger than 6 mm. This illustrates that sulfide coalescence is a critical process. The remaining sulfide blebs define two groups of log-linear particle size distribution (PSD), i.e., a finer group (ESD of 0.080–& .529 mm) and a coarser group (ESD of 0.529–4.084 mm). The PSD of the finer group differs slightly among different types of mineralization. The origin of this group of sulfides is attributed to sulfide nucleation simultaneously with crystallization of the olivine-orthopyroxene-plagioclase phases from the ore-forming magma in the current magma chamber. The PSD of the coarser group from net-textured ores is parallel to that from the disseminated ore but has lower intercept values. Modeling results show that aggregation of ~40–70% sulfide blebs of different grain size from the disseminated ore into the networks can generate the coarser group sulfide PSD of net-textured ore. In addition, monosulfide solution (MSS, pyrrhotite component)-enriched sulfide globules are commonly located close to sulfide matrix ore breccias and emulsion-textured ores, rimming the net-textured and massive orebodies. These globules are different from the sulfide component that was in equilibrium with the mafic magma, suggesting they were formed by mechanical remobilization of a cumulus MSS-enriched component from a previously segregated and partially crystallized sulfide pool. These observations, combined with the ubiquitous chilled margin xenoliths in the high-grade ores, suggest that the Kalatongke deposit was the result of voluminous magma flow through the current location accompanied by sulfide reworking and percolation. All these textural characteristics could be explained by emplacement within a laterally propagating bladed dike. Moreover, the deformation recorded in the emulsion-textured and massive ores suggests the fault system remains active during magma solidification, driving downward migration of sulfide from the sulfide pool at magmatic temperature to form vein-type massive ore. We suggest that the Kalatongke deposit formed by magma pulses injecting into the current location and that the tectonic movement remains active during the solidification of the intrusion. The syntectonic emplacement model, which may be a common feature in the Central Asian orogenic belt Ni-Cu deposits, indicates that the fault systems beneath the intrusion are of great exploration interest for high-grade ores.
The occurrence and origin of pentlandite-chalcopyrite-pyrrhotite loop textures in magmatic Ni-Cu sulfide ores
Publisher: Society of Economic Geologists
Date: 24-08-2020
DOI: 10.5382/ECONGEO.4757
Abstract: Pentlandite is the dominant Ni-hosting ore mineral in most magmatic sulfide deposits and has conventionally been interpreted as being entirely generated by solid-state exsolution from the high-temperature monosulfide solid solution (MSS) (Fe,Ni)1–xS. This process gives rise to the development of loops of pentlandite surrounding pyrrhotite grains. Recently it has been recognized that not all pentlandite forms by exsolution. Some may form as the result of peritectic reaction between early formed MSS and residual Ni-Cu–rich sulfide liquid during differentiation of the sulfide melt, such that at least some loop textures may be genuinely magmatic in origin. Testing this hypothesis involved microbeam X-ray fluorescence mapping to image pentlandite-pyrrhotite-chalcopyrite intergrowths from a range of different deposits. These deposits exemplify slowly cooled magmatic environments (Nova, Western Australia Sudbury, Canada), globular ores from shallow-level intrusions (Norilsk, Siberia), extrusive komatiite-hosted ores from low and high metamorphic-grade terranes, and a number of other deposits. Our approach was complemented by laser ablation-inductively coupled plasma-mass spectrometry analysis of palladium in varying textural types of pentlandite within these deposits. Pentlandite forming coarse granular aggregates, together with loop-textured pentlandite where chalcopyrite also forms part of the loop framework, consistently has the highest Pd content compared with pentlandite clearly exsolved as lamellae from MSS or pyrrhotite. This is consistent with much of granular and loop pentlandite being formed by peritectic reaction between Pd-rich residual sulfide liquid and early crystallized MSS, rather than forming entirely by subsolidus grain boundary exsolution from MSS, as has hitherto been assumed. The wide range of Pd contents in pentlandite in in idual s les reflects a continuum of processes between peritectic reaction and grain boundary exsolution. Textures in metamorphically recrystallized ores are distinctly different from loop-textured ores, implying that loop textures cannot be regenerated (except in special circumstances) by metamorphic recrystallization of original magmatic-textured ores. The presence of loop textures can therefore be taken as evidence of a lack of penetrative deformation and remobilization at submagmatic temperatures, a conclusion of particular significance to the interpretation of the Nova deposit as having formed synchronously with the peak of regional deformation at temperatures within the sulfide melting range.
Introduction to a Special Issue on the Norilsk-Talnakh Ni-Cu-Platinum Group Element Deposits
Publisher: Society of Economic Geologists
Date: 09-2020
DOI: 10.5382/ECONGEO.4750
Nova – Bollinger Ni – Cu Sulfide Ore Deposits, Fraser Zone, Western Australia: Petrogenesis of the Host Intrusions
Publisher: Society of Economic Geologists
Date: 03-2021
DOI: 10.5382/ECONGEO.4873
Abstract: The Nova-Bollinger Ni-Cu sulfide ore deposit is the first economic Ni-Cu-Co sulfide deposit to have been discovered in the Albany-Fraser orogen in Western Australia. The host rocks are mafic-ultramafic intrusive cumulates sub ided into two connected intrusions, designated Upper and Lower. The Upper Intrusion is bowl-shaped and modally layered with alternating peridotite and norite mesocumulate layers, with a Basal Series of dominantly orthocumulate mafic lithologies. The Lower Intrusion is a much thinner, semiconformable chonolith (flattened tube-shaped intrusion) consisting of mostly unlayered mafic to ultramafic orthocumulates. The Lower Intrusion hosts all the high-grade mineralization and most of the disseminated ores. A distinctive plagioclase-bearing lherzolite containing both orthopyroxene and olivine as cumulus phases is a characteristic of the Lower Intrusion and the Basal Series of the Upper. The intrusions differ slightly in olivine and spinel chemistry, the differences being largely attributable to the more orthocumulate character of the Lower Intrusion. Sector zoning in Cr content of pyroxenes is observed in the Lower Intrusion and in the lower marginal zone of the Upper and is attributed to crystallization under supercooled conditions. Symplectite pyroxene-spinel- hibole coronas at olivine-plagioclase contacts are ubiquitous and are attributed to near-solidus peritectic reaction between olivine, plagioclase, and liquid during and after high-pressure emplacement, consistent with high Al contents in igneous pyroxenes and estimates of the peak regional metamorphism. Original cumulus olivines had compositions around Fo86 and were variably Ni depleted, interpreted as the result of preintrusion equilibration with sulfide liquid. The Upper and Lower Intrusion rocks represent cumulates from a similar parental magma, a high-Al tholeiite with MgO between 10 and 12%, low TiO2 (0.5–0.6%), and high Al2O3 (14–17%). Modeling using alphaMELTS indicates a primary water content of around 2 wt %. The cumulates of both intrusions were derived via multiple magma pulses of liquid-olivine-sulfide slurries with variable amounts of orthopyroxene emplaced into the deep crust at pressures of around 0.7 GPa during the peak of regional metamorphism. The intrusions developed initially as a bifurcating sill, the lower arm developing into the ore-bearing Lower Intrusion chonolith and the upper arm inflating into the cyclically layered Upper Intrusion.
A revised oxygen barometry in sulfide-saturated magmas and application to the Permian magmatic Ni–Cu deposits in the southern Central Asian Orogenic Belt
Publisher: Springer Science and Business Media LLC
Date: 29-11-2017
Mapping bedrock lithologies through in situ regolith using retained element ratios: a case study from the Agnew-Lawlers area, Western Australia
Publisher: Informa UK Limited
Date: 17-02-2014
Life on the edge: microbial biomineralization in an arsenic- and lead-rich deep-sea hydrothermal vent
Publisher: Elsevier BV
Date: 02-2020
Idiomorphic oikocrysts of clinopyroxene produced by a peritectic reaction within a solidification front of the Bushveld Complex
Publisher: Springer Science and Business Media LLC
Date: 2021
Timing, geochemistry and tectonic setting of Ni-Cu sulfide-associated intrusions of the Halls Creek Orogen, Western Australia
Publisher: Elsevier BV
Date: 08-2018
Reaction coronas at olivine-plagioclase contacts in host rocks from the Nova-Bollinger Ni-Cu-Co deposit, Albany-Fraser Orogen, Western Australia: evidence of a magmatic to metamorphic continuum
Publisher: Oxford University Press (OUP)
Date: 21-06-2021
DOI: 10.1093/PETROLOGY/EGAB055
Abstract: A prominent feature of the cumulate rocks of the Nova intrusions is the presence of reaction coronas between olivine and plagioclase. A particular spatial arrangement of mineral textures, typical of olivine–plagioclase coronas in high-P troctolites and olivine gabbros worldwide, is almost universally observed: partially resorbed olivine with a cuspate margin, surrounded by orthopyroxene, surrounded by a zone of symplectite comprising hornblende + clinopyroxene, orthopyroxene and Cr-poor Al–(Fe, Mg) spinel, with a cuspate boundary against plagioclase. Where hibole-free clinopyroxene–spinel symplectite is developed it is typically as an outer layer against plagioclase. The mineralogy and composition of these coronas has been revealed by a combination of scanning electron microscopy and synchrotron X-ray fluorescence microscopy. There is a close spatial association between reaction symplectites and Bowen reaction series sequences developed by reaction between cumulus phases and fractionated trapped interstitial melt, giving rise to local Cr and Ti enrichment within the coronas relative to olivine and plagioclase, accompanying enrichment in water recorded by stabilization of hibole. These relationships imply that trapped liquid crystallization and corona formation were part of a process continuum, such that the coronas record mineral reactions close to the solidus temperature of the cumulates, initially developing in the presence of evolved hydrous interstitial liquid and continuing to develop in the solid state below the solidus. The symplectites owe their fine microstructure to diffusion-limited growth of the products of solid-state reactions below the solidus. The initial magmatic stage of corona formation records conditions of 0·76 and 0·96 GPa and around 1035 °C based on THERMOCALC pseudosections calculated for the bulk composition of the corona assemblage. Two-pyroxene assemblages within the symplectites record temperatures around 850–900 °C and pressures between 0·7 and 1·1 GPa. These pressure estimates are in good agreement with those obtained from regional metamorphism studies of the country rock paragneisses, confirming independent lines of evidence that the Nova intrusions were syn-metamorphic, emplaced under granulite-facies peak metamorphic conditions at crustal depths of 28–35 km. The unusually extensive development of the symplectites reflects the cooling history of the intrusions, which remained at temperatures close to solidus temperatures on the timescale of regional tectonic uplift and cooling of the deep roots of the orogen.
Merensky-type platinum deposits and a reappraisal of magma chamber paradigms
Publisher: Springer Science and Business Media LLC
Date: 19-06-2019
DOI: 10.1038/S41598-019-45288-8
Abstract: Most of the world’s economically-viable platinum deposits occur as ‘reefs’ in layered intrusions – thin layers of silicate rocks that contain sulphides enriched in noble metals. There are two contrasting magmatic hypotheses for their formation. The first suggests accumulation through gravity-induced settling of crystals onto the magma chamber floor. The alternative argues for in situ crystallization, i . e . upward growth from the floor. Here we report on our discovery of the Merensky Reef in the Bushveld Complex that occurs on subvertical to overturned margins of depressions in a temporary chamber floor. Such relationships preclude crystal settling and demonstrate that the reef crystallized in situ . This finding indicates that platinum deposits can grow directly at the chamber floor, with immiscible sulfide droplets sequestering ore-forming noble metals from strongly convecting silicate magmas. Our model also provides evidence for the paradigm that argues for magma chambers being masses of nearly crystal-free melt, which gradually loses heat and crystallizes from the margins inward.
Rapid mineralogical and geochemical characterisation of the Fisher East nickel sulphide prospects, Western Australia, using hyperspectral and pXRF data
Publisher: Elsevier BV
Date: 11-2017
Hydrothermal remobilisation around a deformed and remobilised komatiite-hosted Ni-Cu-(PGE) deposit, Sarah’s Find, Agnew Wiluna greenstone belt, Yilgarn Craton, Western Australia
Publisher: Springer Science and Business Media LLC
Date: 08-09-2016
The effect of trapped liquid crystallization on cumulus mineral compositions in layered intrusions
Publisher: Springer Science and Business Media LLC
Date: 08-1986
DOI: 10.1007/BF00371722
Deformed Chromitite Layers in the Coobina Intrusion, Pilbara Craton, Western Australia
Publisher: Society of Economic Geologists
Date: 21-02-2013
Dedication to Professor Hazel Prichard BSc, PhD, MBA (1954–2017)
Publisher: Elsevier BV
Date: 11-2017
Sulfide-silicate textures in magmatic Ni-Cu-PGE sulfide ore deposits: Disseminated and net-textured ores
Publisher: Mineralogical Society of America
Date: 03-2017
DOI: 10.2138/AM-2017-5754
Blade-shaped dikes and nickel sulfide deposits: A model for the emplacement of ore-bearing small intrusions
Publisher: Society of Economic Geologists
Date: 05-2018
Oxide-Sulfide-Melt-Bubble Interactions in Spinel-Rich Taxitic Rocks of the Norilsk-Talnakh Intrusions, Polar Siberia
Publisher: Society of Economic Geologists
Date: 09-2020
DOI: 10.5382/ECONGEO.4748
Abstract: Oxide-rimmed, spherical structures interpreted as former gas bubbles have been discovered within a chromitiferous taxitic lithology of the Norilsk-Talnakh intrusions. These rocks are represented by variable grain size, presence of reworked country-rock xenoliths and millimeter- to centimeter-scale irregular spinel-rich aggregates, patches, or disrupted seams and stringers. They contain spherical and subspherical agglomerations that we interpret as amygdules, partially or completely filled with low-temperature hydrothermal minerals and locally with magmatic phases including sulfide globules. In places these amygdules form clusters that are interpreted as former bubble foams. The wetting relationships visible between vapor bubbles, silicate melt, sulfide liquid, and oxide were investigated in detail using 3-D μX-ray tomography and detailed 2-D X-ray fluorescence maps. They also reveal short-range spatial variability in silicate and oxide minerals, reflecting small-scale advanced fractionation of silicate melt. Three possible mechanisms are considered for the formation of these bubble-spinel foams: (1) the abundant spinel allows for the in situ nucleation of vapor bubbles, (2) the vapor bubbles ascend through the magma and collect spinel, or (3) the vapor bubbles cause rapid nucleation of chromite within these layers. Although none of these mechanisms can be exclusively ruled out, the texture and chemistry of the Norilsk-Talnakh chromitiferous taxitic lithology is most indicative of in situ nucleation of vapor bubbles on spinel surfaces (i.e., mechanism 1).
Relationship between microstructures and grain-scale trace element distribution in komatiite-hosted magmatic sulphide ores
Publisher: Elsevier BV
Date: 2014
Postmagmatic Variability in Ore Composition and Mineralogy in the T4 and T5 Ore Shoots at the High-Grade Flying Fox Ni-Cu-PGE Deposit, Yilgarn Craton, Western Australia
Publisher: Society of Economic Geologists
Date: 08-2012
Poikilitic chromite in komatiitic cumulates
Publisher: Springer Science and Business Media LLC
Date: 1995
DOI: 10.1007/BF01162760
Silicate and oxide mineral chemistry and textures of the Norilsk-Talnakh Ni-Cu-Platinum Group Element ore-bearing intrusions
Publisher: Society of Economic Geologists
Date: 09-2020
DOI: 10.5382/ECONGEO.4747
Abstract: A large proportion of the disseminated sulfide ores of the Norilsk-Talnakh c are hosted within olivine-rich, ultramafic cumulate layers called picro-gabbrodolerite units. In this study we quantitatively analyze the chemistry and textures of the silicate and oxide minerals within olivine-bearing cumulates of the Kharaelakh, Norilsk 1, and Talnakh intrusions to determine how these intrusions compare to each other and to establish the liquidus phase assemblage and crystallization sequence and how the liquid component evolved during solidification. Crystal size distributions indicate that much of the olivine and clinopyroxene oikocrysts grew together in situ as the first of the cumulus phases at contrasting growth rates. These large clinopyroxene oikocrysts record a significant drop in Cr in the system by a significant decrease in Cr content of the outer rims compared to the cores. The chadacrysts of olivine and spinel within the clinopyroxene record the chemistry of the first stages of crystallization, while the minerals in the framework of the cumulate show a relative reduction in Cr and enrichment in incompatible elements such as Ti, Zn, Y, and the rare earth elements, indicative of the enrichment through reactions with the trapped liquid during postcumulate growth. Due to the entrapment of the olivine and spinel in rapidly growing clinopyroxene, these minerals record a history of the changing chemistry during cumulate and postcumulate growth, giving us an insight into the changing conditions during the solidification of intrusions.
Quantitative assessment of the relative roles of sulfide liquid collection, magmatic degassing and fluid-mediated concentration of PGE in low-sulfide ores of the Norilsk intrusions
Publisher: Elsevier BV
Date: 09-2022
Zoned orthopyroxenes in the Ni-Co sulfide ore-bearing Xiarihamu mafic-ultramafic intrusion in northern Tibetan Plateau, China: Implications for multiple magma replenishments
Publisher: Elsevier BV
Date: 10-2019
REVIEW OF PREDICTIVE AND DETECTIVE EXPLORATION TOOLS FOR MAGMATIC NI-CU-(PGE) DEPOSITS, WITH A FOCUS ON KOMATIITE-RELATED SYSTEMS IN WESTERN AUSTRALIA
Publisher: Elsevier
Date: 2018
Anomalous sulfur-poor platinum group element mineralization in komatiitic cumulates, Mount Clifford, Western Australia
Publisher: Society of Economic Geologists
Date: 09-2009
Review of lithogeochemical exploration tools for komatiite-hosted Ni-Cu-(PGE) deposits
Publisher: Elsevier BV
Date: 09-2016
Maia X-ray fluorescence imaging: Capturing detail in complex natural samples
Publisher: IOP Publishing
Date: 03-04-2014
The Archean Fortescue large igneous province: A result of komatiite contamination by a distinct Eo-Paleoarchean crust
Publisher: Elsevier BV
Date: 06-2018
Komatiites and nickel sulfide ores of the Black Swan area, Yilgarn Craton, Western Australia. 1. Petrology and volcanology of host rocks
Publisher: Springer Science and Business Media LLC
Date: 29-10-2004
Deposition Mechanisms of Magmatic Sulphide Liquids: Evidence from High-Resolution X-Ray Computed Tomography and Trace Element Chemistry of Komatiite-hosted Disseminated Sulphides
Publisher: Oxford University Press (OUP)
Date: 23-04-2013
Lithogeochemical exploration for komatiite-associated Ni-sulfide deposits: strategies and limitations
Publisher: Springer Science and Business Media LLC
Date: 12-2004
Pt and Pd mobility in hydrothermal fluids: evidence from komatiites and from thermodynamic modelling
Publisher: Elsevier BV
Date: 02-2012
Microchemical and sulfur isotope constraints on the magmatic and hydrothermal evolution of the Black Swan Succession, Western Australia
Publisher: Springer Science and Business Media LLC
Date: 30-05-2019
Micron-scale distribution of metals in Cambrian metalliferous shales, South China: Insights into local biologically driven redox disequilibrium
Publisher: Elsevier BV
Date: 12-2019
The concentration of platinum-group elements and gold in southern African and Karelian kimberlite-hosted mantle xenoliths: Implications for the noble metal content of the Earth's mantle
Publisher: Elsevier BV
Date: 04-2012
Petrogenesis of the ∼2·77 Ga Monts de Cristal Complex, Gabon: Evidence for Direct Precipitation of Pt-arsenides from Basaltic Magma
Publisher: Oxford University Press (OUP)
Date: 07-2015
The mineral system approach applied to magmatic Ni-Cu-PGE sulphide deposits
Publisher: Elsevier BV
Date: 07-2014
Distribution of sulphides and PGE within the porphyritic websterite zone of the Munni Munni Complex, Western Australia
Publisher: Informa UK Limited
Date: 07-1992
Iridium, ruthenium and rhodium in komatiites: Evidence for iridium alloy saturation
Publisher: Elsevier BV
Date: 11-2008
The Santa Rita Nickel Sulfide Deposit in the Fazenda Mirabela Intrusion, Bahia, Brazil: Geology, Sulfide Geochemistry, and Genesis
Publisher: Society of Economic Geologists
Date: 10-10-2011
Chromitite layers indicate the existence of large, long-lived, and entirely molten magma chambers
Publisher: Springer Science and Business Media LLC
Date: 08-03-2022
DOI: 10.1038/S41598-022-08110-6
Abstract: The classical paradigm of the ‘big magma tank’ chambers in which the melt differentiates, is replenished, and occasionally feeds the overlying volcanos has recently been challenged on various grounds. An alternative school of thought is that such large, long-lived and largely molten magma chambers are transient to non-existent in Earth’s history. Our study of stratiform chromitites in the Bushveld Complex—the largest magmatic body in the Earth’s continental crust—tells, however, a different story. Several chromitites in this complex occur as layers up to 2 m in thickness and more than 400 kms in lateral extent, implying that chromitite-forming events were chamber-wide phenomena. Field relations and microtextural data, specifically the relationship of 3D coordination number, porosity and grain size, indicate that the chromitites grew as a 3D framework of touching chromite grains directly at the chamber floor from a basaltic melt saturated in chromite only. Mass-balance estimates imply that a few km thick column of this melt is required to form each of these chromitite layers. Therefore, an enormous volume of melt appears to have been involved in the generation of all the Bushveld chromitite layers, with half of this melt being expelled from the magma chamber. We suggest that the existence of thick and laterally extensive chromitite layers in the Bushveld and other layered intrusions supports the classical paradigm of big, albeit rare, ‘magma tank’ chambers.
Chapter 6 - Distribution and geochemistry of komatiites and basalts through the Archean
Publisher: Elsevier
Date: 2019
Palladium complexation in chloride- and bisulfide-rich fluids: Insights from ab initio molecular dynamics simulations and X-ray absorption spectroscopy
Publisher: Elsevier BV
Date: 07-2015
Archean komatiite volcanism controlled by the evolution of early continents
Publisher: Proceedings of the National Academy of Sciences
Date: 23-06-2014
Abstract: Komatiites are rare, ultra-high-temperature (∼1,600 °C) lavas that were erupted in large volumes 3.5–1.5 bya but only very rarely since. They are the signature rock type of a hotter early Earth. However, the hottest, most extensive komatiites have a very restricted distribution in particular linear belts within preserved Archean crust. This study used a combination of different radiogenic isotopes to map the boundaries of Archean microcontinents in space and time, identifying the microplates that form the building blocks of Precambrian cratons. Isotopic mapping demonstrates that the major komatiite belts are located along these crustal boundaries. Subsequently, the evolution of the early continents controlled the location and extent of major volcanic events, crustal heat flow, and major ore deposit provinces.
Ruthenium in komatiitic chromite
Publisher: Elsevier BV
Date: 07-2011
The Maia detector array and x-ray fluorescence imaging system: locating rare precious metal phases in complex samples
Publisher: SPIE
Date: 26-09-2013
DOI: 10.1117/12.2027195
Constraints on the origin of the Skaergaard intrusion magmatic Cu-Pd-Au mineralization: insights from high-resolution X-ray computed tomography
Publisher: Elsevier BV
Date: 03-2014
An Issue Devoted to Magmatic Sulfide Mineralization and Ore Deposits with Special Emphasis on China: Preface
Publisher: Society of Economic Geologists
Date: 04-11-2013
Platinum group elements in mantle melts and mantle samples
Publisher: Elsevier BV
Date: 09-2015
Geochemistry of komatiites in the Southern Cross Belt, Youamni Terrane, Western Australia
Publisher: Informa UK Limited
Date: 07-2012
Application of lithogeochemistry in the assessment of nickel-sulphide potential in komatiite belts from northern Finland and Norway
Publisher: The Geological Society of Finland
Date: 12-2013
Growth history of sphalerite in a modern sea floor hydrothermal chimney revealed by electron backscattered diffraction
Publisher: Society of Economic Geologists
Date: 02-2019
Time scales and length scales in magma flow pathways and the origin of magmatic Ni–Cu–PGE ore deposits
Publisher: Elsevier BV
Date: 2019
Effects of hydrous alteration on the distribution of base metals and platinum group elements within the Kevitsa magmatic nickel sulphide deposit
Publisher: Elsevier BV
Date: 2016
Sulfide-silicate textures in magmatic Ni-Cu-PGE sulfide ore deposits: Massive, semi-massive and sulfide-matrix breccia ores
Publisher: Elsevier BV
Date: 10-2018
Lithogeochemistry in exploration for intrusion-hosted magmatic Ni-Cu-Co deposits
Publisher: Geological Society of London
Date: 02-02-2023
Abstract: Magmatic Ni–Cu–Co–platinum group element deposits are notoriously difficult exploration targets owing to a lack of alteration haloes or other extended distal footprints. Success requires prediction of prospective terranes, followed by identification of suitable host intrusions and deposition sites within those intrusions. At the regional scale, potential ore-hosting magmas tend to have lithophile trace element trends falling on mixing lines between primitive or slightly depleted source mantle and typical upper continental crust, with several significant exceptions. Most known deposits have parent magmas that are in the upper range of FeO content for given MgO compared with baseline data sets for continental large igneous province magmas. At the scale of in idual intrusions, the presence of cumulate rocks, both mafic and ultramafic, is key. These can be recognized in regional datasets using combinations of magnesium number (molar MgO/(MgO + FeO), Al 2 O 3 , TiO 2 and Zr contents. Combinations of alteration-resistant element ratios between Ni, Cr and Ti are also useful and can also be applied to moderately weathered s les. Concentrations and ratios of Cu and Zr are useful in discriminating chalcophile-enriched and depleted magma suites. In combination, these approaches can be combined to discriminate highly prospective cumulate-dominated magmatic suites and in idual intrusions from non-cumulate suites with limited potential. Supplementary material: Supplementary Appendix 1, procedure for determination of FeO–MgO contents of magmas from olivine-liquid mixing lines, and Supplementary Appendix 2, procedure and error analysis for correcting major element whole rock analyses volatile and sulfide free, are available at 0.6084/m9.figshare.c.6267664
The role of fluids in the metamorphism of komatiites, Agnew nickel deposit, Western Australia
Publisher: Springer Science and Business Media LLC
Date: 06-1987
DOI: 10.1007/BF00375229
Paragenesis of multiple platinum-group mineral populations in Shetland ophiolite chromitite: 3D X-ray tomography and in situ Os isotopes
Publisher: Elsevier BV
Date: 11-2017
Element mapping the Merensky Reef of the Bushveld Complex
Publisher: Elsevier BV
Date: 05-2021
Platinum-group element and gold contents of arsenide and sulfarsenide minerals associated with Ni and Au deposits in Archean greenstone belts
Publisher: Mineralogical Society
Date: 13-04-2018
DOI: 10.1180/MINMAG.2017.081.100
Abstract: Post-magmatic alteration of certain magmatic Ni sulfide ores in Western Australia, the Miitel deposit and the Sarah's Find prospect, produced Ni–As–PGE haloes around massive sulfides. A study of the composition of arsenide grains from these hydrothermal haloes, along with arsenides from various magmatic and hydrothermal mineralized environments in other localities, was conducted in order to compare their composition, and assess their potential use as indicator minerals for exploration vectoring, as well as to gain knowledge on their crystallization history. Concentrations in trace elements such as platinum-group elements (PGEs), Au and other metals was obtained by laser ablation inductively coupled plasma mass spectroscopy analyses. Results show that variations in PGEs and Au compositions can be related to the magmatic vs. hydrothermal origin of the grains and to their provenance from deposits enriched in either Ni, Au or both. Magmatic NiCoFe sulfarsenides have strongly correlated, high IPGE (Os, Ir, Ru, Rh) contents up to 100 ppm Ir, compared with maximum values in hydrothermal sulfarsenides of ~1 ppm. Gold in hydrothermal sulfarsenides from Au-mineralized ultramafic rocks extends up to 500 ppm, with typical values of 3–30 ppm similar values are also found in nickeline (also called niccolite). These results suggest that nickel arsenides could potentially be used as indicator minerals for nickel and gold exploration. Trace-element contents of arsenide grains in shear zones could be used to deduce the presence of Ni or Au mineralization upstream in the fluid pathway.
Simplifying drill-hole domains for 3D geochemical modelling: an example from the Kevitsa Ni-Cu-(PGE) deposit
Publisher: Elsevier BV
Date: 11-2017
Role of degassing of the Noril’sk nickel deposits in the Permian–Triassic mass extinction event
Publisher: Proceedings of the National Academy of Sciences
Date: 21-02-2017
Abstract: The Noril’sk deposits represent one of the most valuable metal concentrations on Earth and are associated with the world’s largest outpouring of mafic magma. Mass release of nickel into the atmosphere during ore formation has been postulated as one of the triggers for the Permian–Triassic Mass Extinction Event, by promoting the activity of the marine Archaea methanosarcina with catastrophic greenhouse climatic effects. The missing link has been understanding how nickel, normally retained at depth in magmatic minerals, could have been mobilized into magmatic gases. The flotation of magmatic sulfides to the surface by gas bubbles was suggested as a possible mechanism. Here, we provide evidence of physically attached nickel-rich sulfide droplets and former gas bubbles, frozen into the Noril’sk ores.
Zoned pyroxenes as prospectivity indicators for magmatic Ni-Cu sulfide mineralization
Publisher: Frontiers Media SA
Date: 10-07-2020
pyrolite: Python for geochemistry
Publisher: The Open Journal
Date: 09-06-2020
DOI: 10.21105/JOSS.02314
Evolution of the Munali Intrusive Complex: Host to a carbonate-rich Ni-(Cu-PGE) sulfide deposit
Publisher: Elsevier BV
Date: 11-2022
Komatiites and Nickel Sulfide Ores of the Black Swan area, Yilgarn Craton, Western Australia. 2. Geology and Genesis of the Orebodies
Publisher: Springer Science and Business Media LLC
Date: 29-10-2004
Chrome spinels from the Jinchuan Ni-Cu sulphide deposit, Gansu Province, Peoples' Republic of China
Publisher: Society of Economic Geologists
Date: 05-1999
Partitioning of the platinum group elements and gold between silicate and sulphide magmas in the Munni Munni Complex, Western Australia
Publisher: Elsevier BV
Date: 03-1993
Variability of sulfur isotopes and trace metals in pyrites from the upper oceanic crust of the South China Sea basin, implications for sulfur and trace metal cycling in subsurface
Publisher: Elsevier BV
Date: 09-2022
Komatiite Magmas and Sulfide Nickel Deposits: A Comparison of Variably Endowed Archean Terranes
Publisher: Society of Economic Geologists
Date: 08-2012
Geochemistry of Archaean komatiites from the Forrestania Greenstone Belt, Western Australia: evidence for supracrustal contamination
Publisher: Elsevier BV
Date: 04-1996
Spatial variation in platinum group element concentrations in ore-bearing komatiite at the long-victor deposit, Kambalda dome, Western Australia: Enlarging the footprint of nickel sulfide orebodies
Publisher: Society of Economic Geologists, Inc.
Date: 08-2013
DOI: 10.2113/ECONGEO.108.5.913
Abstract: The detectable footprints of komatiite-hosted nickel sulfide deposits are typically very small, but can potentially be enlarged by identifying subtle geochemical variations related to ore-forming processes in the host rocks. This study examines the spatial variability of whole-rock concentrations of platinum group elements (PGEs) within the host flow to massive nickel sulfide mineralization at the Long-Victor deposit, Kambalda dome (Western Australia), where a series of ore shoots occupy two subparallel channels, over a strike length of approximately 3,000 m. The basal komatiite flow unit at Long-Victor contains a wide range of platinum group element concentrations and PGE/Ti ratios in S-poor rocks outside the ore shoots. About a third of the s les analyzed show evidence for either enrichment or depletion in PGEs, as estimated from mantle-normalized ratios of Pt/Ti, Pd/Ti, and Rh/Ti, relative to background values typical of those found in Neoarchean Munro-type komatiites worldwide. The very strong correlations observed between Pt/Ti, Pd/Ti, and Rh/Ti testify to a primary magmatic origin of this signal. Depletion signatures are largely restricted to s les in the flanking environment within the basal flow, and are found both in spinifex-textured A-zone and cumulate B-zone s les. The strongest depletion signatures are preserved in the uppermost portions of the A-zone and decrease in magnitude with increasing depth from the stratigraphic top of the spinifex horizon downward. This is interpreted as the result of progressive flushing of the flow channel by PGE-undepleted lava subsequent to ore formation. Enriched signatures are largely restricted to cumulate rock types, and are found within both channels and flanks. The halo of anomalous PGE/Ti ratios, both depleted and enriched, extends more than 400 m from the cutoff of 0.4% Ni that defines the limit of disseminated ores, and is much more extensive and marked than anomalies defined by Ni concentrations, Ni/Cr ratios, or Ni/Ti ratios, which extend no more than 20 m beyond the disseminated ores themselves. The PGE enrichment halo is recognizable in rocks having no visible sulfide and having Ni values falling within the silicate background, and is attributed to the accumulation of small proportions of PGE-rich disseminated sulfide liquid formed at high R factors, with subsequent loss of S during hydrothermal alteration. Mapping of PGE/Ti ratios provides an effective and sensitive method for vectoring toward ore during mine-scale and prospect-scale exploration, and is potentially applicable to mafic systems as well as to komatiites.
A molecular and isotopic study of palaeoenvironmental conditions through the middle Cambrian in the Georgina Basin, central Australia
Publisher: Elsevier BV
Date: 08-2016
Magmatic sulfide ore deposits
Publisher: Mineralogical Society of America
Date: 04-2017
Crystallization of spinel from coexisting silicate and sulfide immiscible liquids: An equilibrium case with postcumulus reactions
Publisher: Mineralogical Society of America
Date: 05-2023
DOI: 10.2138/AM-2022-8473
Abstract: Spinel minerals occur as inclusions in both silicates and sulfides in the Kalatongke magmatic Ni-Cu deposit in NW. China, showing textural and compositional variations. The spinel enclosed in olivine and other silicates (orthopyroxene, clinopyroxene, and hornblende) is predominantly Cr-magnetite with minor Cr-spinel, having wide variations in MgO (0.1–8.0 wt%), Al2O3 (1–25 wt%), Cr2O3 (3–20 wt%), and TiO2 (0.5–6.2 wt%) contents. Such continuous variations suggest that Cr-magnetite in silicates was crystallized from residual melts and experienced extensive reaction with trapped liquid undergoing a typical tholeiitic trend of increasing Fe and Ti concentrations. Crystals of Cr-magnetite enclosed in disseminated sulfides have similar Mg, Al, Cr, Ti, V, Sc, Ga, Mo, Zr, and Nb concentrations to the Cr-magnetite in silicates. Such compositional similarity, which is explained by the simultaneous equilibrium crystallization of Cr-magnetite from the silicate and sulfide melts, shows that the Kalatongke deposit is a typical ex le of where the same mineral phase is formed from two coexisting immiscible liquids. However, the Cr-magnetite in disseminated sulfide and that in silicates show distinctly different crystal size distribution patterns, illustrating that the chemical equilibrium was attained despite contrasting growth rates. Nevertheless, the Cr-magnetite in disseminated sulfides shows significantly lower Ni, Co, and Zn contents (median value of 845, 22, and 319 ppm) than that in silicates (median value of 1428, 160, and 1039 ppm). This cannot be the result of sulfide fractionation because there is little compositional variation between Cr-magnetite included in pyrrhotite (early crystallized phase) and that immersed in chalcopyrite (late crystallized phase). Such Ni, Co, and Zn depletions, combined with the relatively constrained Fe/Ni, Fe/Co, and Fe/Zn ratios in those Cr-magnetite, are attributed to postcumulus reactions between Cr-magnetite and sulfide melts. The spinel hosted by massive sulfides is magnetite, which has distinctly different compositional variations and crystal size distribution patterns compared with those of the silicate-hosted Cr-magnetite, although the magnetite in massive ore generally has similar contents in some lithophile elements (Zr, Ta, Mo, Sn, Mn) to the silicate-hosted Cr-magnetite. This could be taken as evidence for a mixture of early accumulated sulfide pools with a component of drained sulfide from the cumulates above. This study shows a detailed textural and compositional investigation of spinel is useful to decode the sulfide evolution processes during the formation of magmatic Ni-Cu deposits and highlights that equilibrium crystallization and postcumulus reactions play critical roles in controlling the spinel/magnetite composition.
Atypical stratiform sulfide-poor platinum-group element mineralisation in the Agnew – Wiluna Belt komatiites, Wiluna, Western Australia
Publisher: Informa UK Limited
Date: 08-2007
Extremely Ni-rich Fe-Ni sulfide assemblages in komatiitic dunite at Betheno, Western Australia: results from synchrotron X-ray fluorescence mapping
Publisher: Informa UK Limited
Date: 10-2011
Nickel-copper sulfide mineralization in the Ntaka Hill ultramafic complex, Nachingwea region, Tanzania
Publisher: Society of Economic Geologists
Date: 09-2019
DOI: 10.5382/ECONGEO.4677
Abstract: The Ntaka Hill Ni-Cu deposit in Tanzania lies within the Mozambique belt, a complex, long-lived Neoproterozoic suture zone that formed during the amalgamation of Gondwana. The deposit is hosted within the moderately deformed Ntaka Ultramafic Complex, which was emplaced at ~660 Ma, around 20 m.y. before the East African orogeny. Due to strain partitioning into hibolites and metapyroxenites at the margins of the sills, magmatic cumulate textures are very well preserved. The Ntaka Hill mineralization is predominantly disseminated sulfides within orthopyroxenites and harzburgites. Sulfides show typical magmatic mineralogy and occur as isolated blebs and interstitial networks as well as in soft-walled segregation veins that form localized shoot-like high-grade zones. Deformation had relatively little effect on the deposition of sulfides other than minor localization of strain within some preexisting sulfide-dominant veins. Grade shells define elongate tubular channels that coincide broadly with the more magnesian cumulate rocks. Base and precious metal tenors are widely variable, ranging from 1 to 17% Ni and 0.5 to 10% Cu with no particular correlation with host-rock type, although the tenor range in the more magnesian cumulates is more restricted, with the low-tenor component ( % Ni, % Cu) missing. Olivine compositions vary widely, with forsterite contents ranging from Fo84 to Fo89 with up to 0.85% NiO. These unusually high Ni contents are attributed to equilibration with high-Ni-tenor sulfides percolating through the intercumulus pore space. Complex zoning patterns in the Cr content of orthopyroxenes record fluctuating crystallization conditions attributed to wall-rock assimilation. The intrusion emplacement setting is interpreted to be derived from a flow of xenolith-, crystal-, and sulfideladen magma through channelized sills where much of the sulfide was incompletely equilibrated with the host magma, resulting in highly variable R-factors. Despite the widespread presence of graphite in the marginal pyroxenites, olivine-sulfide Fe/Ni partitioning records typical redox conditions that are slightly more oxidized than quartz-fayalite-magnetite (QFM)—further evidence of a lack of extensive large-scale equilibrium within the intrusive complex. The Ntaka Ultramafic Complex preserves an arrested stage of the amalgamation of small sulfide-bearing sill-sediment complex intrusions into larger convecting magma chambers, forming one end of a process continuum including Kevitsa (Finland) as an intermediate stage and Mirabela (Brazil) as the layered intrusion end member.
Partial melting and recrystallization of Archaean komatiites by residual heat from rapidly accumulated flows
Publisher: Springer Science and Business Media LLC
Date: 11-1990
DOI: 10.1007/BF00306535
Primary stratigraphic controls on ore mineral assemblages in the Wannaway komatiite-hosted nickel-sulfide deposit, Kambalda camp, Western Australia
Publisher: Elsevier BV
Date: 11-2017
Morphology and microstructure of chromite crystals in chromitites from the Merensky Reef (Bushveld Complex, South Africa)
Publisher: Springer Science and Business Media LLC
Date: 29-12-2013
Trace-element geochemistry and petrogenesis of barren and ore-associated komatiites
Publisher: Mineralogical Association of Canada
Date: 04-2001
Investigation of the Internal Structure of a Modern Seafloor Hydrothermal Chimney With a Combination of EBSD, EPMA, and XRD
Publisher: Oxford University Press (OUP)
Date: 20-05-2020
DOI: 10.1017/S1431927620001580
Abstract: S les from the sphalerite-dominated zone of a seafloor massive sulfide chimney, the Satanic Mills Chimney of the PACMANUS hydrothermal field, have been investigated to determine the internal macrostructure and microstructure of this zone, the phases present, and the distribution of metals. A combination of electron probe microanalysis, electron backscattered diffraction, and x-ray diffraction has been used. At the macroscale, this zone of the chimney wall is heavily porous and is comprised primarily of sphalerite, enclosing minor chalcopyrite, pyrite, and wurtzite. A Pb – As sulfosalt layer of possible microbial origins is present at the outer edge of the sphalerite matrix, next to a pore. The sphalerite has grown in globules on the order of 300 μ m in diameter. At the microscale, the sphalerite features a colloform texture and a duplex-type grain structure consisting of either fine-grain regions in the center surrounded by coarse-grained regions or radiating coarse grains only. Pb- and As-rich bands have been detected in the colloform sphalerite, and growth twins have been observed in both the sphalerite and chalcopyrite crystals. A qualitative description of the growth of a typical globule is given, including nucleation, crystal growth, and solute redistribution.
Are Bushveld U-type parent magmas boninites or contaminated komatiites?
Publisher: Springer Science and Business Media LLC
Date: 04-1989
DOI: 10.1007/BF00372218
Archean andesites in the east Yilgarn craton, Australia: Products of plume-crust interaction?
Publisher: GeoScienceWorld
Date: 04-2014
DOI: 10.1130/L356.1
Effects of magmatic processes, serpentinization and talc carbonate alteration on sulfide mineralogy and ore textures in the Black Swan disseminated nickel sulfide deposit, Yilgarn Craton
Publisher: Society of Economic Geologists
Date: 07-2009
Characterisation of nickel sulphide ore samples from the Rosie Nickel Prospect
Publisher: CSIRO
Date: 2010
Crustal evolution, intra-cratonic architecture and the metallogeny of an Archaean craton
Publisher: Geological Society of London
Date: 03-12-2013
DOI: 10.1144/SP393.8
Cotectic precipitation of olivine and sulfide liquid from komatiite magma, and the origin of komatiite-hosted disseminated nickel sulfide mineralization at Mt Keith and Yakabindie, Western Australia
Publisher: Society of Economic Geologists
Date: 03-2007
The distribution of Cr, Ni, and chromite in komatiites, and application to exploration for komatiite-hosted nickel sulfide deposits
Publisher: Society of Economic Geologists
Date: 02-1999
Supplemental Material: Role of volatiles in intrusion emplacement and sulfide deposition in the supergiant Norilsk-Talnakh Ni-Cu-PGE ore deposits
Publisher: Geological Society of America
Date: 09-08-2023
Abstract: Geological map (regional and local geology) and stratigraphic column of Paleozoic sedimentary sequence and of the in idual ore-hosting intrusions.
Poikilitic textures, heteradcumulates and zoned orthopyroxenes in the Ntaka Ultramafic Complex, Tanzania: Implications for crystallization mechanisms of oikocrysts
Publisher: Oxford University Press (OUP)
Date: 06-2016
A relic of the Mozambique Ocean in south-east Tanzania
Publisher: Elsevier BV
Date: 02-2018
Transport of metals and sulphur in magmas by flotation of sulphide melt on vapour bubbles
Publisher: Springer Science and Business Media LLC
Date: 23-02-2015
DOI: 10.1038/NGEO2373
Related Organisations
Commonwealth Scientific And Industrial Research Organisation
Location: Australia
Related Funding Activities
Linkage Infrastructure, Equipment And Facilities - Grant ID: LE180100070
Start Date: 2018
End Date: 03-2019
Amount: $966,283.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE0989649
Start Date: 04-2009
End Date: 07-2010
Amount: $800,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP190102422
Start Date: 07-2019
End Date: 07-2023
Amount: $300,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP120100668
Start Date: 11-2012
End Date: 11-2014
Amount: $130,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE200100035
Start Date: 2020
End Date: 06-2023
Amount: $610,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE150100013
Start Date: 2015
End Date: 12-2015
Amount: $860,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE120100095
Start Date: 01-2012
End Date: 12-2013
Amount: $620,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE150100006
Start Date: 2015
End Date: 12-2015
Amount: $1,060,000.00
Funder: Australian Research Council
View Funded Activity