DOI: 10.1016/j.epsl.2018.06.012
Scopus记录号: 2-s2.0-85048977999
论文题名: Sulfur isotope and PGE systematics of metasomatised mantle wedge
作者: Rielli A. ; Tomkins A.G. ; Nebel O. ; Raveggi M. ; Jeon H. ; Martin L. ; Ávila J.N.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 497 起始页码: 181
结束页码: 192
语种: 英语
英文关键词: garnet peridotite
; oxygen fugacity
; PGE
; porphyry deposits
; subduction metasomatism
; sulfur isotopes
Scopus关键词: Copper deposits
; Deposits
; Flow of fluids
; Garnets
; Isotopes
; Mineralogy
; Oxidation
; Ruthenium
; Structural geology
; Sulfur compounds
; Garnet peridotite
; Oxygen fugacity
; Porphyry deposits
; subduction metasomatism
; Sulfur isotope
; Gold deposits
英文摘要: At convergent margins fluids liberated from subducting slabs metasomatise the overlying mantle wedge, enriching it in volatiles, incompatible elements and possibly ore-forming metals. Despite the genetic link between this process, the genesis of arc magmas, and formation of porphyry Cu–Au deposits, there is currently little understanding of the behaviour of chalcophile and siderophile elements during subduction-related mantle metasomatism. In this study, we report sulfur isotopic compositions and PGE concentrations of sulfides in a suite of garnet peridotites from the Western Gneiss Region of Norway, sampling mantle wedge from ∼100 to ∼250 km depth. Sulfides hosted in metasomatised samples have δ34S deviated from typical mantle values, ranging between −10.0 and +5.4‰, indicating derivation of sulfur from subducted crust. Sulfides in pervasively metasomatised samples have atypical PGE signatures, with strong enrichment in Os and Ru relative to Ir, whereas channelised fluid flow produced sulfides extremely enriched in Pd, up to 700 times the concentration found in non-metasomatised samples. These signatures are reconcilable with a high oxidation state of the metasomatising agents and demonstrate that subduction can recycle chalcophile and siderophile elements into and within the mantle, along with sulfur. We further show that because the solubility of Os and Ru in fluids is redox sensitive, and Pd is more soluble than the I-PGE, ratios such as Os/Ir, Ru/Ir plotted against Pd/Ir can be used to trace the metasomatic oxidation of mantle samples, mantle-derived magmas and porphyry Cu±Au deposits. This geochemical insight is used to show that Au-rich porphyry Cu deposits are derived from more oxidised mantle wedge than Au-poor porphyry deposits. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109786
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria 53, Pisa, 56126, Italy; School of Earth, Atmosphere and the Environment, Monash University, Melbourne, Victoria 3800, Australia; Centre for Microscopy, Characterisation, and Analysis, ARC Centre of Excellence for Core to Crust Fluid Systems (CCFS), University of Western Australia, Australia; Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia
Recommended Citation:
Rielli A.,Tomkins A.G.,Nebel O.,et al. Sulfur isotope and PGE systematics of metasomatised mantle wedge[J]. Earth and Planetary Science Letters,2018-01-01,497