Sulfide metasomatism and the mobility of gold in the lithospheric mantle
Gold is a strongly chalcophile element and its concentration and behaviour in the mantle are intimately connected to the nature, abundance and mobility of sulfide phases. In this study Au has been analysed together with a suite of chalcophile and siderophile elements in sulfides hosted in 31 mantle-...
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ftunivnewengland:oai:rune.une.edu.au:1959.11/20114 2023-08-27T04:12:17+02:00 Sulfide metasomatism and the mobility of gold in the lithospheric mantle Saunders, James School of Environmental and Rural Science orcid:0000-0002-6728-789X Pearson, N J O'Reilly, Suzanne Y Griffin, W L 2015 https://hdl.handle.net/1959.11/20114 en eng Elsevier BV 10.1016/j.chemgeo.2015.06.016 https://hdl.handle.net/1959.11/20114 une:20312 Igneous and Metamorphic Petrology Journal Article 2015 ftunivnewengland 2023-08-10T19:02:56Z Gold is a strongly chalcophile element and its concentration and behaviour in the mantle are intimately connected to the nature, abundance and mobility of sulfide phases. In this study Au has been analysed together with a suite of chalcophile and siderophile elements in sulfides hosted in 31 mantle-derived xenoliths from Spitsbergen in the Svalbard Archipelago. These data have been combined with analysis of silicate phases to assess the mobility of Au, and sulfides in general, during mantle processes. The 31 samples comprise lherzolites, harzburgites, dunites and a wehrlite. Several lherzolites contain amphibole and apatite, and two are cross-cut by amphibole veins. The REE patterns in clinopyroxene reveal three geochemically distinct groups of peridotites. Group I samples have flat or LREE depleted patterns ((La/Yb)n1). The sulfides hosted in the Group I samples have very heterogeneous Au compositions (1.9 ± 1.4 ppm), whereas those hosted in Groups II and III samples have lower and more homogenous Au concentrations (Group II Au: 0.66 ± 0.60 ppm; Group III Au: 0.53 ± 0.57 ppm). A chromatographic metasomatic model is proposed to explain the variations between the three groups of samples. The LREE enrichment, and common inclusion of amphibole in the Group III samples is consistent with modification by a carbonate-rich melt. It is interpreted that these samples were located close to the metasomatic conduit. The sulfide homogeneity in these samples results from extensive equilibration with the metasomatic agent; Au has partitioned into the fluid phase, reducing the Au content of these sulfides. The Group I samples show little to no metasomatic alteration in the silicate phases, indicating they were located far from the conduit. The agents that have affected these samples have been modified by extensive fractionation and wall-rock interaction during percolation through the mantle, becoming enriched in Au. Group II samples are inferred to have been located at an intermediate distance from the conduit with silicate and ... Article in Journal/Newspaper Svalbard Spitsbergen Research UNE - University of New England at Armidale, NSW Australia Svalbard Svalbard Archipelago |
institution |
Open Polar |
collection |
Research UNE - University of New England at Armidale, NSW Australia |
op_collection_id |
ftunivnewengland |
language |
English |
topic |
Igneous and Metamorphic Petrology |
spellingShingle |
Igneous and Metamorphic Petrology Saunders, James School of Environmental and Rural Science orcid:0000-0002-6728-789X Pearson, N J O'Reilly, Suzanne Y Griffin, W L Sulfide metasomatism and the mobility of gold in the lithospheric mantle |
topic_facet |
Igneous and Metamorphic Petrology |
description |
Gold is a strongly chalcophile element and its concentration and behaviour in the mantle are intimately connected to the nature, abundance and mobility of sulfide phases. In this study Au has been analysed together with a suite of chalcophile and siderophile elements in sulfides hosted in 31 mantle-derived xenoliths from Spitsbergen in the Svalbard Archipelago. These data have been combined with analysis of silicate phases to assess the mobility of Au, and sulfides in general, during mantle processes. The 31 samples comprise lherzolites, harzburgites, dunites and a wehrlite. Several lherzolites contain amphibole and apatite, and two are cross-cut by amphibole veins. The REE patterns in clinopyroxene reveal three geochemically distinct groups of peridotites. Group I samples have flat or LREE depleted patterns ((La/Yb)n1). The sulfides hosted in the Group I samples have very heterogeneous Au compositions (1.9 ± 1.4 ppm), whereas those hosted in Groups II and III samples have lower and more homogenous Au concentrations (Group II Au: 0.66 ± 0.60 ppm; Group III Au: 0.53 ± 0.57 ppm). A chromatographic metasomatic model is proposed to explain the variations between the three groups of samples. The LREE enrichment, and common inclusion of amphibole in the Group III samples is consistent with modification by a carbonate-rich melt. It is interpreted that these samples were located close to the metasomatic conduit. The sulfide homogeneity in these samples results from extensive equilibration with the metasomatic agent; Au has partitioned into the fluid phase, reducing the Au content of these sulfides. The Group I samples show little to no metasomatic alteration in the silicate phases, indicating they were located far from the conduit. The agents that have affected these samples have been modified by extensive fractionation and wall-rock interaction during percolation through the mantle, becoming enriched in Au. Group II samples are inferred to have been located at an intermediate distance from the conduit with silicate and ... |
format |
Article in Journal/Newspaper |
author |
Saunders, James School of Environmental and Rural Science orcid:0000-0002-6728-789X Pearson, N J O'Reilly, Suzanne Y Griffin, W L |
author_facet |
Saunders, James School of Environmental and Rural Science orcid:0000-0002-6728-789X Pearson, N J O'Reilly, Suzanne Y Griffin, W L |
author_sort |
Saunders, James |
title |
Sulfide metasomatism and the mobility of gold in the lithospheric mantle |
title_short |
Sulfide metasomatism and the mobility of gold in the lithospheric mantle |
title_full |
Sulfide metasomatism and the mobility of gold in the lithospheric mantle |
title_fullStr |
Sulfide metasomatism and the mobility of gold in the lithospheric mantle |
title_full_unstemmed |
Sulfide metasomatism and the mobility of gold in the lithospheric mantle |
title_sort |
sulfide metasomatism and the mobility of gold in the lithospheric mantle |
publisher |
Elsevier BV |
publishDate |
2015 |
url |
https://hdl.handle.net/1959.11/20114 |
geographic |
Svalbard Svalbard Archipelago |
geographic_facet |
Svalbard Svalbard Archipelago |
genre |
Svalbard Spitsbergen |
genre_facet |
Svalbard Spitsbergen |
op_relation |
10.1016/j.chemgeo.2015.06.016 https://hdl.handle.net/1959.11/20114 une:20312 |
_version_ |
1775356272317562880 |