Sulfides and chalcophile elements in Roberts Victor eclogites: Unravelling a sulfide-rich metasomatic event

doi:10.1016/j.chemgeo.2013.06.015

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	Sulfides and chalcophile elements in Roberts Victor eclogites: Unravelling a sulfide-rich metasomatic event
	Greau, Yoann 1,2,3; Alard, Olivier 1,2,3; Griffin, William L.1,2; Huang, Jin-Xiang 1,2,4; O'Reilly, Suzanne Y.1,2
刊名	CHEMICAL GEOLOGY
	2013-09-16
卷号	354 页码:73-92
关键词	Eclogite Xenoliths Sulfides Mantle Metasomatism Sub-continental Lithospheric Mantle Chalcophile Elements
DOI	10.1016/j.chemgeo.2013.06.015
文献子类	Article
英文摘要	A suite of eclogite xenoliths from the Roberts Victor kimberlite (South Africa) is remarkable for its high abundances of base metal sulfides (BMS; up to 2 modal %). However, while sulfides are nearly ubiquitous in Type I eclogites (garnet >0.07% Na2O), Type II eclogites (garnet b0.07% Na2O) systematically lack sulfides. Two different sulfide assemblages are recognisedwithin the Type I xenolith suite. Both populations are polyphase Cu-Ni-Fe sulfides, one characterised by the pyrrhotite (Po) + pentlandite (Pn) + chalcopyrite (Cp) assemblage and the other by the smythite/violarite (Smy/Vi) + (Ni) pyrite (Py) + Cp assemblage. The latter is the most abundant assemblage and reflects the supergene alteration of the " primary" Po + Pn + Cp assemblage. This process overprints the original composition of the sulfides by remobilising elements such as S, Fe, Ni, Se and Te. In the Type I eclogites, BMS occur as inclusions within silicates (garnet and clinopyroxene) and as interstitial grains. No chemical differences were observed between enclosed and interstitial sulfides. However, their relative abundances are correlated, indicating a similar origin. The Po + Pn + Cp assemblage is identical to eclogitic sulfides previously described in some Roberts Victor diamonds. Silicate-enclosed sulfides could appear to be early phases, but they are restricted to the outer parts of the silicate grains, suggesting a late incorporation during partial recrystallisation of silicate phases, induced by fluid-rock percolation-reaction during a metasomatic event. Positive whole-rock correlations between Se and (La/Sm) N. and between Cu and SLREEN. indicate a direct link between sulfide content and the enrichment of Mg + incompatible elements in the Type I eclogites, further supporting a metasomatic origin of the sulfide component. Similarly, a negative correlation between SLREEN. and Cucpx implies that the metasomatic agent was at least partially composed of S-rich fluid (e. g. H2S, SO2) that reacted with the rock and leached Cu out of the silicates. The coupling between sulfides and LREE in the Type I eclogites, as well as the absence of sulfides and metasomatic features (e. g. unequilibrated grain boundaries, melt pockets, fluid inclusions, phlogopite) in the Type II eclogites, demonstrate that Type II eclogites did not undergo such a metasomatic event and therefore may represent the less-modified protoliths of Type I eclogites. (C) 2013 Elsevier B. V. All rights reserved.
WOS关键词	PLATINUM-GROUP ELEMENTS ; HIGHLY SIDEROPHILE ELEMENTS ; ANCIENT OCEANIC-CRUST ; ARIEGE NORTHEASTERN PYRENEES ; RE-OS SYSTEMATICS ; FE-NI SULFIDES ; SOUTH-AFRICA ; LITHOSPHERIC MANTLE ; PERIDOTITE XENOLITHS ; SPINEL-LHERZOLITE
WOS研究方向	Geochemistry & Geophysics
语种	英语
WOS记录号	WOS:000325751200008
资助机构	Macquarie University international postgraduate scholarships ; Macquarie University international postgraduate scholarships ; ARC (Australian Research Council) Discovery and Linkage Grants ; ARC (Australian Research Council) Discovery and Linkage Grants ; DEST Systemic Infrastructure Grants ; DEST Systemic Infrastructure Grants ; ARC LIEF ; ARC LIEF ; NCRIS ; NCRIS ; Macquarie University international postgraduate scholarships ; Macquarie University international postgraduate scholarships ; ARC (Australian Research Council) Discovery and Linkage Grants ; ARC (Australian Research Council) Discovery and Linkage Grants ; DEST Systemic Infrastructure Grants ; DEST Systemic Infrastructure Grants ; ARC LIEF ; ARC LIEF ; NCRIS ; NCRIS
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/62640]
专题	地质与地球物理研究所_岩石圈演化国家重点实验室
作者单位	1.Macquarie Univ, ARC Ctr Excellence Core Crust Fluid Syst, N Ryde, NSW 2109, Australia 2.Macquarie Univ, GEMOC Natl Key Ctr, Dept Earth & Planetary Sci, N Ryde, NSW 2109, Australia 3.Univ Montpellier 2, CNRS, Equipe Manteau & Interfaces, UMR 5243, F-34095 Montpellier 5, France 4.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing, Peoples R China
推荐引用方式 GB/T 7714	Greau, Yoann,Alard, Olivier,Griffin, William L.,et al. Sulfides and chalcophile elements in Roberts Victor eclogites: Unravelling a sulfide-rich metasomatic event[J]. CHEMICAL GEOLOGY,2013,354:73-92.
APA	Greau, Yoann,Alard, Olivier,Griffin, William L.,Huang, Jin-Xiang,&O'Reilly, Suzanne Y..(2013).Sulfides and chalcophile elements in Roberts Victor eclogites: Unravelling a sulfide-rich metasomatic event.CHEMICAL GEOLOGY,354,73-92.
MLA	Greau, Yoann,et al."Sulfides and chalcophile elements in Roberts Victor eclogites: Unravelling a sulfide-rich metasomatic event".CHEMICAL GEOLOGY 354(2013):73-92.