Variation in trace element content of magnetite crystallized from a fractionating sulfide liquid, Sudbury, Canada: Implications for provenance discrimination

Dare, Sarah A. S.; Barnes, Sarah‐Jane; Beaudoin, Georges

doi:10.1016/j.gca.2012.04.032

Cited by 273 publications

(187 citation statements)

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“…The Ti-poor nature of the resultant oxides indicates that these are not the primary igneous oxides that crystallized from the sulfide melt (Dare et al 2012;Larocque et al 2000). Their formation at high temperature by S loss is suggested by the lack of alteration in the silicate assemblages; however, one cannot discount the ability of low to ambient temperature alteration to be sulfide-specific owing to kinetic constraints.…”

Section: Discussionmentioning

confidence: 99%

A study of the trace sulfide mineral assemblages in the Stillwater Complex, Montana, USA

et al. 2016

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The sulfide assemblages of the Stillwater Complex away from the well-studied ore zones are composed mainly of variable proportions of pyrrhotite, chalcopyrite, pentlandite, and ±pyrite. Excluding vein assemblages and those affected by greenschist and lower temperature alteration, the majority can be classified into two broad assemblages, defined here as pristine (multiphase, often globular in shape) or volatilebearing (multiphase, high-temperature, volatile-rich minerals such as biotite, hornblende, or an unmixed calcite-dolomite assemblage). The volatile-bearing assemblages are mainly found within and below the J-M reef, where native copper and sphalerite are also locally present. Pristine sulfides are found throughout the stratigraphy. Both groups can be affected by apparent S loss in the form of pyrite being converted to magnetite and chalcopyrite to a Cu-Fe-oxide (delafossite), with little to no silicate alteration. An upward trend from pentlandite-rich to pyrrhotite-rich to pyrite-rich assemblages is observed in the footwall rocks in upper GN-I, and the same trend repeats from just below the reef and continues into the overlying N-II and GN-II. Modeling suggests that the sulfide Ni in the Peridotite Zone is largely controlled by silicate Ni. When taken together, observations are most readily explained by the remobilization of selected elements by a hightemperature fluid with the apparent loss of S > Cu > Ni. This could concentrate ore metals by vapor refining, eventually producing a platinum group element-enriched sulfide ore zone, such as the J-M reef.

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Section: Discussionmentioning

confidence: 99%

A study of the trace sulfide mineral assemblages in the Stillwater Complex, Montana, USA

et al. 2016

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“…Recently, Dare et al (2012) compiled data on partition coefficients for major and trace elements between magnetite and melt, using the Geochemical Earth Reference Model database (http://earthref.org/GERM/). Partitioning of Al, Mg, and Mn between magnetite and melt strongly depends on the melt composition and the presence of co-existing silicate minerals because they are lithophile elements.…”

Section: Methodsmentioning

confidence: 99%

“…It may also depend on mineral compositions, temperature, and oxygen fugacity; however, Toplis and Corgne (2002) reported that partitioning of divalent cations into magnetite is approximately independent of oxygen fugacity in spite of the fact that magnetite composition is a strong function of oxygen fugacity. For the magma compositions investigated here (calc-alkaline andesite), it is known that lithophile elements such as Mg (Mg/Mn) and Al decrease in magnetite during fractionation of a silicate melt (e.g., Dare et al 2012). Thus, we here refer to a zoning pattern that shows an increase in Al and Mg toward the rim as "reverse zoning.…”

Section: Methodsmentioning

confidence: 99%

Short time scales of magma-mixing processes prior to the 2011 eruption of Shinmoedake volcano, Kirishima volcanic group, Japan

et al. 2013

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We estimated time scales of magma-mixing processes just prior to the 2011 sub-Plinian eruptions of Shinmoedake volcano to investigate the mechanisms of the triggering processes of these eruptions. The sequence of these eruptions serves as an ideal example to investigate eruption mechanisms because the available geophysical and petrological observations can be combined for interpretation of magmatic processes. The eruptive products were mainly phenocryst-rich (28 vol%) andesitic pumice (SiO 2 57 wt%) with a small amount of more silicic pumice (SiO 2 62-63 wt%) and banded pumice. These pumices were formed by mixing of low-temperature mushy silicic magma (dacite) and high-temperature mafic magma (basalt or basaltic andesite). We calculated the time scales on the basis of zoning analysis of magnetite phenocrysts and diffusion calculations, and we compared the derived time scales with those of volcanic inflation/deflation observations. The magnetite data revealed that a significant mixing process (mixing I) occurred 0.4 to 3 days before the eruptions (preeruptive mixing) and likely triggered the eruptions. This mixing process was not accompanied by significant crustal deformation, indicating that the process was not accompanied by a significant change in volume of the magma chamber. We propose magmatic overturn or melt accumulation within the magma chamber as a possible process. A subordinate mixing process (mixing II) also occurred only several hours before the eruptions, likely during magma ascent (syn-eruptive mixing). However, we interpret mafic injection to have begun more than several tens of days prior to mixing I, likely occurring with the beginning of the inflation (December 2009). The injection did not instantaneously cause an eruption but could have resulted in stable stratified magma layers to form a hybrid andesitic magma (mobile layer). This hybrid andesite then formed the main eruptive component of the 2011 eruptions of Shinmoedake.

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“…Trace-element data for magnetites (remnant), ilmenites and hematite from Nuggihalli are compared with data for magmatic Fe-Ti-V-P-rich magnetites from the upper parts of layered intrusions like the Bushveld Complex (South Africa) and the Sept Iles (Canada), from intermediate and felsic magmas like andesite and Granite-I type magmas, from high-(>500 °C) and low-temperature (<500 °C) hydrothermal fluids (Dare et al 2014) and from massive Ni-Cu (PGE)-rich deposits like Sudbury (Dare et al 2012). …”

Section: Trace-element Fingerprint Of Magnetitementioning

confidence: 99%

“…In situ trace-element analysis using laser ablation ICP-MS (LA-ICPMS) has revolutionized petrogenetic studies as one can investigate the minerals of interest without interference from the surrounding phases (e.g., Dare et al 2009Dare et al , 2011Dare et al , 2012Pagé and Barnes 2009;González-Jiménez et al 2013Pagé et al 2012;Colás et al 2014). Compared to major elements in chromites, the trace elements are more sensitive to parameters like temperature and oxygen fugacity, and they therefore show larger variations during partial melting and fractional crystallization (Dare et al 2009;González-Jiménez et al 2013.…”

Section: Introductionmentioning

confidence: 99%

Trace-element fingerprints of chromite, magnetite and sulfides from the 3.1 Ga ultramafic–mafic rocks of the Nuggihalli greenstone belt, Western Dharwar craton (India)

Mukherjee

Mondal

Gonzáléz-Jiménez

et al. 2015

Contrib Mineral Petrol

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LA-ICPMS) of unaltered chromites indicates that the parental magma of the chromitite ore-bodies was a komatiite lacking nickel-sulfide mineralization. In the Ga/Fe 3+ # versus Ti/Fe 3+ # diagram, the Byrapur chromites plot in the field of suprasubduction zone (SSZ) chromites while those from Bhaktarhalli lie in the MOR field. The above results corroborate our previous results based on majorelement characteristics of the chromites, where the calculated parental melt of the Byrapur chromites was komatiitic to komatiitic basalt, and the Bhaktarhalli chromite was derived from Archean high-Mg basalt. The major-element chromite data hinted at the possibility of a SSZ environment existing in the Archean. Altered and compositionally zoned chromite grains in our study show a decrease in Ga, V, Co, Zn, Mn and enrichments of Ni and Ti in the ferritchromit rims. Trace-element heterogeneity in the altered chromites is attributed to serpentinization. The trace-element patterns of magnetite from the massive magnetite bands in the greenstone belt are similar to those from magmatic Fe-Ti-V-rich magnetite bands in layered intrusions, and magnetites from andesitic melts, suggesting that magnetite crystallized from an evolved gabbroic melt. Enrichments of Ni, Co, Te, As and Bi in disseminated millerite and niccolite occurring within chromitites, and in disseminated bravoite within magnetites, reflect element mobility during serpentinization. Monosulfide solid solution inclusions within pyroxenes (altered to actinolite) in pyroxenite, and interstitial pyrites and chalcopyrites in magnetite, retain primary characteristics except for Fe-enrichment in chalcopyrite, probably due to sub-solidus re-equilibration with magnetite. Disseminated sulfides are depleted in platinum-group elements (PGE) due to late sulfide saturation and the PGE-depleted nature of the mantle source of the sill-like ultramafic-mafic plutonic rocks in the Nuggihalli greenstone belt. AbstractThe 3.1 Ga Nuggihalli greenstone belt in the Western Dharwar craton is comprised of chromitite-bearing sill-like ultramafic-mafic rocks that are surrounded by metavolcanic schists (compositionally komatiitic to komatiitic basalts) and a suite of tonalite-trondhjemite-granodiorite gneissic rocks. The sill-like plutonic unit consists of a succession of serpentinite (after dunite)-peridotite-pyroxenite and gabbro with bands of titaniferous magnetite ore. The chromitite ore-bodies (length ≈30-500 m; width ≈2-15 m) are hosted by the serpentinite-peridotite unit. Unaltered chromites from massive chromitites (>80 % modal chromite) of the Byrapur and Bhaktarhalli chromite mines in the greenstone belt are characterized by high Cr# (100Cr/(Cr + Al)) of 78-86 and moderate Mg# (100 Mg/ (Mg + Fe 2+ )) of 45-55. In situ trace-element analysis Communicated by Timothy L. Grove. Electronic supplementary materialThe online version of this article (

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Variation in trace element content of magnetite crystallized from a fractionating sulfide liquid, Sudbury, Canada: Implications for provenance discrimination

Cited by 273 publications

References 53 publications

A study of the trace sulfide mineral assemblages in the Stillwater Complex, Montana, USA

A study of the trace sulfide mineral assemblages in the Stillwater Complex, Montana, USA

Short time scales of magma-mixing processes prior to the 2011 eruption of Shinmoedake volcano, Kirishima volcanic group, Japan

Trace-element fingerprints of chromite, magnetite and sulfides from the 3.1 Ga ultramafic–mafic rocks of the Nuggihalli greenstone belt, Western Dharwar craton (India)

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