Platinum-group elements and gold in the komatiite-hosted Fe-Ni-Cu sulfide deposits at Kambalda, Western Australia

Cowden, Alistair; Donaldson, Mike; Naldrett, A. J.; Campbell, Ian H.

doi:10.2113/gsecongeo.81.5.1226

Cited by 35 publications

(19 citation statements)

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“…It is possible that the experimental conditions are not applicable to Kambalda and that Zn partitioned more strongly into sulfide magma than the silicate magma, but it is not clear that a partition coefficient as high as 6 is justified. We obviously need better constraints on D Zn Sul/Sil , but if it is less than 6, the relatively high Zn contents of Kambalda ores (200-400 ppm: Cowden et al 1986) require an external source. A value of 2.5 produces results that are compatible with the other elements.…”

Section: Metal Variations At Kambaldamentioning

confidence: 99%

MULTICOMPONENT ELEMENTAL AND ISOTOPIC MIXING IN Ni Cu (PGE) ORES AT KAMBALDA, WESTERN AUSTRALIA

Lesher

Burnham

2001

The Canadian Mineralogist

126

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Most magmatic Ni-Cu-(PGE) deposits are considered to have formed from sulfide-undersaturated silicate magmas and to contain a significant component of crustal sulfur that was derived via wholesale melting, partial melting, or devolatilization of wall rocks. Under such circumstances, the system may comprise a silicate magma and a sulfide magma, with or without crystalline solids, undissolved wallrock-derived xenoliths, an unmixed silicate xenomelt, or an undissolved xenovolatile phase, each of which may contain distinct chalcophile and lithophile components. Because traditional two-component (silicate magma -sulfide magma) mass-balance models do not accurately model such systems, we have developed a series of multicomponent elemental and isotopic mass-balance equations to model batch equilibration in magmatic Ni-Cu-(PGE) systems. We have applied them to the type examples of komatiite-associated Ni-Cu-(PGE) deposits at Kambalda, Western Australia. The calculations indicate that the elemental and isotopic compositions of the various components in a multicomponent system will vary considerably as a function of the relative abundances of the components, and that different metals and isotopic systems may decouple from each other, yielding apparently conflicting information regarding the sources of the components. The results suggest that the S isotopic and Zn compositions of the ores are more sensitive indicators of contamination than the Os isotopes, and support a sedimentmelting model for Kambalda.

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Section: Metal Variations At Kambaldamentioning

confidence: 99%

MULTICOMPONENT ELEMENTAL AND ISOTOPIC MIXING IN Ni Cu (PGE) ORES AT KAMBALDA, WESTERN AUSTRALIA

Lesher

Burnham

2001

The Canadian Mineralogist

126

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“…22) to explain the presence of chromites on the komatiite-ore interface of the Silver Swan ore body (Black Swan area,Western Australia). Kambalda's massive sulphides are Ni-rich, with Ni/Fe $ 0.30, and relatively Cu-poor with only $1 wt% Cu (Cowden et al, 1986). Murck and Fig.…”

Section: Kambalda (Western Australia)mentioning

confidence: 98%

Oxygen solubility and speciation in sulphide-rich mattes

Fonseca

Campbell

O’Neill

et al. 2008

Geochimica et Cosmochimica Acta

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Sulphide-rich liquids are common in magmatic environments forming over a wide range of temperature, pressure, fO 2 and fS 2 . They are economically important because they sequester valuable metals such as Cu, Ni, Au and Pt from silicate melts. The presence of accessory amounts of primary oxides associated with sulphide mineralisations is often ignored or unexplained. Experimental work has shown that large amounts of oxygen can dissolve into mattes at fO 2 typical of terrestrial environments. At the quartz-fayalite-magnetite fO 2 buffer, the molar fraction of O in the matte exceeds that of S, placing the composition of the matte to the magnetite side of the mss (monosulphide solid solution)-magnetite join in the Fe-S-O system. However, sulphides crystallise before magnetite in most sulphide mineralisations and are much more abundant. Moreover, the speciation of O in a matte is not well known. Here we report the results of an experimental study of the solubility of O in mattes as a function of fS 2 , fO 2 , temperature, and composition. We confirm previous observations that Ni and Cu have a negative effect on the solubility of O in mattes. We show evidence for the existence of FeSO as a structural constituent of mattes in the Fe-S-O system. We present a simple parameterisation of the amount of O dissolved in mattes under relevant geological conditions, and use this parameterisation to discuss mechanisms for the crystallisation of primary spinels associated with sulphides in the Kambalda massive sulphide deposit (Western Australia) and the Sudbury Igneous Complex (Ontario, Canada).

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“…Eruption temperatures of komatiite lavas ranged from 1400 to 1700°C, the lavas were of very low viscosity (~0.1–1 Pa s), and it is widely assumed that they flowed turbulently ( Huppert et al 1984 ; Huppert & Sparks 1985; Hill et al 1995 ; Williams et al 1998 ). The lava is considered to have been focused into ‘channels’, (either open lava rivers, tubes or constructional lava complexes) forming thick, high‐Mg flows ( Gresham & Loftus‐Hills 1981; Lesher et al 1984 ; Cowden 1988; Cowden & Roberts 1990; Hill et al 1995 ), and laminar flowing overspills of lava from the ‘channels’ formed thin sheet flows in ‘flank’ settings.…”

Section: Komatiites and The Kambalda Modelmentioning

confidence: 99%

“…At Kambalda this sulfide mineralisation is now often preserved in trough structures, the origin of which has been widely debated. The troughs have been variably interpreted as: (i) thermal erosion channels, formed by melting and assimilation of the substrate by turbulent komatiite lava ( Huppert et al 1984 ; Huppert & Sparks 1985); (ii) pre‐existing topographic depressions deepened by thermal erosion ± structural modification ( Lesher et al 1984 ; Groves et al 1986 ); or (iii) purely structural features, with sulfide bodies in the channel facies being the focus for subsequent deformation ( Cowden 1988; Cowden & Roberts 1990). The thin flanking flows are observed to conformably overlie either the footwall metabasalt or sulfidic metasedimentary rocks at Kambalda.…”

Section: Komatiites and The Kambalda Modelmentioning

confidence: 99%

Geology of an Archaean metakomatiite succession, Tramways, Kambalda Ni province, Western Australia: Assessing the extent to which volcanic facies architecture and flow emplacement mechanisms can be reconstructed

Moore

Fernand

Beresford

et al. 2000

Australian Journal of Earth Sciences

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The Kambalda Ni province, located in the Archaean Norseman–Wiluna greenstone belt of Western Australia, boasts the largest known concentration of komatiite‐associated magmatic Fe–Ni–Cu sulfide deposits. These are found as long, linear massive to disseminated bodies at the base of a thick komatiite sequence. The sulfide bodies are closely associated with, or contained within, trough structures at the contact with the underlying basaltic unit. In this study, the McComish Prospect, located 40 km south of Kambalda at Tramways, was studied to assess the relationships between volcanic facies, mineralisation and trough structures. The rocks in this region have variably experienced four phases of deformation, upper greenschist – lower amphibolite facies metamorphism, granitoid intrusion, and subsequent alteration. Relict igneous textures are locally preserved at McComish, however, enabling the evaluation of existing geological models and interpretations. The McComish trough is considered to be entirely structural in origin and unrelated to primary volcanic processes (e.g. thermal erosion). The association of volcanic textural facies in individual flow units, and the distribution of flow units across the trough is more complex than predicted by prevailing models, suggesting an alternative komatiite lava emplacement mechanism. Results are consistent with the proposal that komatiites did not flow turbulently as widely accepted, nor did they cool by vigorous convection. Alternatively, the lavas were emplaced as inflated, lobate basalt pahoehoe‐like flows. Although Fe–Ni–Cu sulfide mineralisation at McComish is most likely volcanic in origin, its present distribution appears to be structurally controlled or modified. The zone of weakly to strongly disseminated sulfides at the base of the komatiite sequence is thickened adjacent to a major north‐northwest‐trending fault on the western margin of the trough. This fault is interpreted to have been a fluid conduit, remobilising the ore during metamorphism and deformation.

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Platinum-group elements and gold in the komatiite-hosted Fe-Ni-Cu sulfide deposits at Kambalda, Western Australia

Cited by 35 publications

References 0 publications

MULTICOMPONENT ELEMENTAL AND ISOTOPIC MIXING IN Ni Cu (PGE) ORES AT KAMBALDA, WESTERN AUSTRALIA

MULTICOMPONENT ELEMENTAL AND ISOTOPIC MIXING IN Ni Cu (PGE) ORES AT KAMBALDA, WESTERN AUSTRALIA

Oxygen solubility and speciation in sulphide-rich mattes

Geology of an Archaean metakomatiite succession, Tramways, Kambalda Ni province, Western Australia: Assessing the extent to which volcanic facies architecture and flow emplacement mechanisms can be reconstructed

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