Residual platinum-group minerals from highly depleted harzburgites of the Lherz massif (France) and their role in HSE fractionation of the mantle

Luguet, Ambre; Shirey, Steven B.; Lorand, Jean‐Pierre; Horan, M. F.; Carlson, Richard W.

doi:10.1016/j.gca.2007.04.011

Cited by 229 publications

(169 citation statements)

References 61 publications

(136 reference statements)

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“…In addition, the similar range of variation in 187 Os/ 188 Os values among IPGE-rich alloys and massive chromitites favors a magmatic origin for these highly refractory alloys (Brenker et al 2003). Recently, Luguet et al (2007) established that mm-size PGM, such as Ru-Os±Ir sulfides and PtIr±Os alloys, likely located in the intergranular matrix of depleted harzburgites, account for 50-100% of the budget of highly siderophile elements in these peridotites. The PGM have been interpreted to be residual, having formed by complete consumption of mantle BMS under a high degree of melting (23-24%).…”

Section: The Pgm Of Milia Chromitites Compared To Pgm From Other Chromentioning

confidence: 95%

Chromian Spinel Composition and Platinum-Group Element Mineralogy of Chromitites From the Milia Area, Pindos Ophiolite Complex, Greece

Kapsiotis

Grammatikopoulos

Tsikouras

et al. 2009

The Canadian Mineralogist

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The chromitites of the Milia area in the Pindos ophiolite complex, in Greece, were investigated for their platinum-group mineral (PGM) content. The chromitites are massive, more rarely disseminated in texture and occur as small pods. They are composed of magnesiochromite crystals with Cr# [Cr/(Cr + Al)] between 0.80 and 0.84, and Mg# [Mg/(Mg + Fe 2+ )] between 0.54 and 0.72. The total platinum-group-element (PGE) contents in chromitites are relatively low (≤170 ppb), although they may locally be higher (up to 1059 ppb). The IPGE (Os, Ir and Ru) predominate over the PPGE (Rh, Pt and Pd). The PGM assemblage, consistent with the geochemical data, is dominated by laurite and Os-Ir-Ru alloys that occur both as single and composite grains, generally less than 15 mm in size. Laurite has a wide range of Os-for-Ru substitution [Ru/(Ru + Os): 0.42-0.99], whereas primary alloys are enriched in Ru (up to 73.80 wt.%). Some laurite crystals exhibit an anomalous pattern of zoning. Such zoning requires an inversion of the normal T-f(S 2 ) trend in magmatic systems, and is herein considered to be due to postmagmatic processes. Some Ru-rich alloy grains contain relatively high Rh and Pt abundances, similar to those of residual sulfides in mantle peridotites. This feature suggests that these alloys may represent residual PGM phases from earlier episodes of melt extraction from the severely depleted mantle unit of the Pindos ophiolite complex. Combined compositional data indicate that the Milia chromitites formed from a hydrous boninitic melt in a suprasubduction-zone environment.Keywords: chromitites, platinum-group minerals (PGM), laurite, alloys, ophiolites, Pindos, Greece. Certains grains d'alliages riches en Ru contiennent des teneurs relativement élevées en Rh et Pt, tout comme les sulfures résiduels de péridotites du manteau. Ces grains d'alliage pourraient donc représenter des MGP résiduels après l'extraction antérieure de liquide silicaté, laissant un manteau très stérile dans le complexe ophiolitique de Pinde. Les données combinées sur la composition indiquent que les chromitites de Milia se sont formées à partir d'une magma hydraté boninitique dans un milieu au dessus de la zone de subduction.(Traduit par la Rédaction)

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Section: The Pgm Of Milia Chromitites Compared To Pgm From Other Chromentioning

confidence: 95%

Chromian Spinel Composition and Platinum-Group Element Mineralogy of Chromitites From the Milia Area, Pindos Ophiolite Complex, Greece

Kapsiotis

Grammatikopoulos

Tsikouras

et al. 2009

The Canadian Mineralogist

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“…However, this contrasts with the information recorded in interstitial PGM, thought to have formed from extreme melt depletion in spinel lherzolites from Lherz (Luguet et al 2007). But, as was demonstrated by the radiogenic Kilbourne Hole lherzolite of Harvey et al (2011), analysis of enclosed BMS from otherwise metasomatized peridotites has the potential to "see through" the late events that precipitated radiogenic interstitial BMS and / or PGM and alloys.…”

Section: Osmium Mass Balancementioning

confidence: 77%

“…This review represents the first time that BMS in mantle rocks and diamonds are discussed together for the purposes of age determination. The interested reader should also consult other articles that have discussed these topics individually (e.g., Shirey and Walker 1998;Burton et al 1999Burton et al , 2012Pearson and Shirey 1999;Luguet et al 2001Luguet et al , 2003Luguet et al , 2004Luguet et al , 2007Luguet et al , 2008; Richardson et al 2001Richardson et al , 2004Richardson et al , 2009Shirey et al 2001Shirey et al , 2002Shirey et al , 2004aShirey et al ,b, 2013Alard et al 2002Alard et al , 2005Aulbach et al 2004aAulbach et al ,b, 2009aAulbach et al ,b,c, 2011Harvey et al 2006Harvey et al , 2010Harvey et al , 2011 …”

Section: Introductionmentioning

confidence: 99%

“…The high K d Os is tracked by the behavior and abundance of BMS in the mantle. However, in highly depleted and/or altered peridotites, HSE are often hosted in refractory platinum-group minerals (PGM) and alloys (e.g., Luguet et al 2007;Lorand et al 2013) that have formed from BMS as a consequence of reactions involving melts or fluids. Thus, in strongly melt-depleted and/or altered peridotites, the influence of PGM on Os mass balance should not be ignored.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mantle Sulfides and their Role in Re–Os and Pb Isotope Geochronology

Harvey¹,

Warren²,

Shirey³

2016

Highly Siderophile and Strongly Chalcophile Elements in High-Temperature Geochemistry and Cosmochemistry

Self Cite

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“…The absolute and relative abundances of the siderophile elements in the silicate Earth have been affected by both mantle and crustal processes including melting, metasomatism, crystal-liquid fractionation and crustal recycling [7][8][9]. Many of the siderophile elements are also typically chalcophile, so they are affected by processes that involve the growth and breakdown of sulfides [10,11]. [14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Siderophile element constraints on the origin of the Moon

Walker

2014

Phil. Trans. R. Soc. A.

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Discovery of small enrichments in 182 W/ 184 W in some Archaean rocks, relative to modern mantle, suggests both exogeneous and endogenous modifications to highly siderophile element (HSE) and moderately siderophile element abundances in the terrestrial mantle. Collectively, these isotopic enrichments suggest the formation of chemically fractionated reservoirs in the terrestrial mantle that survived the putative Moon-forming giant impact, and also provide support for the late accretion hypothesis. The lunar mantle sources of volcanic glasses and basalts were depleted in HSEs relative to the terrestrial mantle by at least a factor of 20. The most likely explanations for the disparity between the Earth and Moon are either that the Moon received a disproportionately lower share of late accreted materials than the Earth, such as may have resulted from stochastic late accretion, or the major phase of late accretion occurred prior to the Moon-forming event, and the putative giant impact led to little drawdown of HSEs to the Earth's core. High precision determination of the 182 W isotopic composition of the Moon can help to resolve this issue.

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Residual platinum-group minerals from highly depleted harzburgites of the Lherz massif (France) and their role in HSE fractionation of the mantle

Cited by 229 publications

References 61 publications

Chromian Spinel Composition and Platinum-Group Element Mineralogy of Chromitites From the Milia Area, Pindos Ophiolite Complex, Greece

Chromian Spinel Composition and Platinum-Group Element Mineralogy of Chromitites From the Milia Area, Pindos Ophiolite Complex, Greece

Mantle Sulfides and their Role in Re–Os and Pb Isotope Geochronology

Siderophile element constraints on the origin of the Moon

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