Global Variability in the Platinum-group Element Contents of Komatiites

Fiorentini, Marco L.; Barnes, Stephen J.; Maier, Wolfgang D.; Burnham, O Marcus; Heggie, Geoffrey J.

doi:10.1093/petrology/egq074

Cited by 76 publications

(31 citation statements)

References 86 publications

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“…In contrast, low-degree partial melts, such as typical MORB, are generally characterized by fractionated chondrite-normalized HSE patterns with high Pd/Ir and Pt/Ir ratios (Rehkamper et al, 1999;Bezos et al, 2005;Dale et al, 2008;Ireland et al, 2009). Chondrite-normalized PGE patterns for the estimated Emeishan parental melts are comparable with those of komatiites and parental melts to Hawaiian picrites, which have been attributed to limited retention of I-PGE in their mantle sources due to saturation in Ir-(Os) alloys (e.g., Ireland et al, 2009;Fiorentini et al, 2011). Fractionation between I-PGE and P-PGE suggests the presence of residual sulfide in the plume source (Bennett et al, 2000).…”

Section: Effects Of Partial Melting and Crystal-liquid Fractionationmentioning

confidence: 66%

Chemical heterogeneity of the Emeishan mantle plume: Evidence from highly siderophile element abundances in picrites

Wang

Ren

et al. 2014

Journal of Asian Earth Sciences

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a b s t r a c tHighly magnesian lavas or picrites have the potential to preserve important information about the origin and thermochemical state of the mantle source(s) of large igneous provinces. We have conducted a comprehensive study of highly siderophile element (HSE) concentrations in picrites from the ca. 260 Ma Emeishan large igneous province. We show that HSE abundances in the Emeishan picrites are greater than those in mid-ocean ridge basalts (MORBs) and parental melts of Hawaiian picrites, but are similar to those in komatiites. The picrites have two types of C1-normalized HSE patterns: (a) type 1, as represented by the Muli picrites is similar to that of the primitive upper mantle; (b) type 2, as represented by the Dali picrites resembles East Greenland and Iceland picrites. Pt/Ir and Pd/Ir ratios in the type 2 picrites are higher than those in type 1 picrites. The primary melt compositions of the studied samples have been estimated by back-addition of equilibrium olivine. The calculated HSE abundances of the parental liquids of the Dali and Muli picrites are higher than those of the parental melts to Hawaiian picrites. Along with previously published isotopic data, our study provides further evidence for chemical heterogeneity of the Emeishan mantle plume.

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Section: Effects Of Partial Melting and Crystal-liquid Fractionationmentioning

confidence: 66%

Chemical heterogeneity of the Emeishan mantle plume: Evidence from highly siderophile element abundances in picrites

Wang

Ren

et al. 2014

Journal of Asian Earth Sciences

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“…The main problem with the above model is that the NG2 chills have among the highest Pt contents (and Pt/Pd ratios) of global magmas, yet most crustal lithologies are relatively PGE poor (average of 1.5-2 ppb Pt and Pd each, Schmidt et al 1997). Thus, addition of average lower or upper crust, or the quartzitic footwall rocks (<1 ppb Pt + Pd, Table 3) to komatiite (typically having <10 ppb Pt and Pd, Fiorentini et al 2011) would not result in the observed PGE enrichment, in particular Pt.…”

Section: Crustal Contamination Of Komatiite Derived From the Convectimentioning

confidence: 99%

A chilled margin of komatiite and Mg-rich basaltic andesite in the western Bushveld Complex, South Africa

Maier

Barnes

2016

Contrib Mineral Petrol

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“…The last few decades have seen a significant increase in our understanding of komatiites, particularly their generation, volcanology, geochemistry and associated Ni-Cu -PGE mineralization (Arndt et al 1979;Gresham & Loftus-Hills 1981;Lesher et al 1984;Huppert & Sparks 1985b;Arndt & Jenner 1986;Groves et al 1986;Gole et al 1987;Campbell et al 1989;Herzberg 1992;Hill et al 1995;Blichert-Toft & Arndt 1999;Barnes et al 2004;Fiorentini et al 2010Fiorentini et al , 2011. However, most studies were focused at the deposit scale, whereas the understanding of the controls of komatiite emplacement at the terrane to craton scale has remained largely incomplete.…”

Section: Evaluation Of Sm-nd Data In Space and Timementioning

confidence: 99%

Crustal evolution, intra-cratonic architecture and the metallogeny of an Archaean craton

Mole

Fiorentini

Cassidy

et al. 2013

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The generation of the Earth's continental crust modified the composition of the mantle and provided a stable, buoyant reservoir capable of capturing mantle material and ultimately preserving ore deposits. Within the continental crust, lithospheric architecture and associated cratonic margins are a first-order control on camp-scale mineralization. Here we show that the evolving crustal architecture of the Archaean Yilgarn Craton, Western Australia, played a key role in controlling the localization of camp-scale gold, iron and nickel mineralized systems. The age and source characteristics of Archaean lithosphere are heterogeneous in both space and time and are recorded by the varying Nd isotopic signature of crustal rocks. Spatial and temporal variations in isotopic character document the evolution of an intra-cratonic architecture through time, and in doing so map transient lithospheric discontinuities where gold, nickel and iron mineral systems were concentrated. Komatiite-hosted nickel deposits cluster into camps localized within young, juvenile crust at the isotopic margin with older lithosphere; orogenic gold systems are typically localized along major structures within juvenile crust; and banded iron formation (BIF)-hosted iron deposits are localized at the edge of, and within, older lithospheric blocks. Furthermore, this work shows that crustal evolution plays an important role in the development and localization of favourable sources of nickel, gold and iron by controlling the occurrence of thick BIFs, ultramafic lavas and fertile (juvenile) crust, respectively. Fundamentally, this study demonstrates that the lithospheric architecture of a craton can be effectively imaged by isotopic techniques and used to identify regions prospective for camp-scale mineralization.

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Global Variability in the Platinum-group Element Contents of Komatiites

Cited by 76 publications

References 86 publications

Chemical heterogeneity of the Emeishan mantle plume: Evidence from highly siderophile element abundances in picrites

Chemical heterogeneity of the Emeishan mantle plume: Evidence from highly siderophile element abundances in picrites

A chilled margin of komatiite and Mg-rich basaltic andesite in the western Bushveld Complex, South Africa

Crustal evolution, intra-cratonic architecture and the metallogeny of an Archaean craton

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