Geology, mineralogy, S and Sr isotope geochemistry, and fluid inclusion analysis of barite associated with the Lemarchant Zn–Pb–Cu–Ag–Au-rich volcanogenic massive sulphide deposit, Newfoundland, Canada
Barite in the approximately 513 Ma Lemarchant volcanogenic massive sulphide (VMS) deposit, Newfoundland, consists of granular and bladed barite intimately associated with mineralization. Regardless of type, the composition of barite is homogeneous at bulk rock and mineral scale containing predominan...
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crcansciencepubl:10.1139/cjes-2018-0161 2024-09-09T19:53:38+00:00 Geology, mineralogy, S and Sr isotope geochemistry, and fluid inclusion analysis of barite associated with the Lemarchant Zn–Pb–Cu–Ag–Au-rich volcanogenic massive sulphide deposit, Newfoundland, Canada Lajoie, Marie-Ève Piercey, Stephen J. Conliffe, James Layton-Matthews, Daniel 2020 http://dx.doi.org/10.1139/cjes-2018-0161 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjes-2018-0161 http://www.nrcresearchpress.com/doi/pdf/10.1139/cjes-2018-0161 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 57, issue 1, page 133-166 ISSN 0008-4077 1480-3313 journal-article 2020 crcansciencepubl https://doi.org/10.1139/cjes-2018-0161 2024-06-20T04:11:56Z Barite in the approximately 513 Ma Lemarchant volcanogenic massive sulphide (VMS) deposit, Newfoundland, consists of granular and bladed barite intimately associated with mineralization. Regardless of type, the composition of barite is homogeneous at bulk rock and mineral scale containing predominantly Ba, S, and Sr, with minor Ca and Na. The barite has homogeneous sulphur isotope compositions (δ 34 S mean = 27‰), similar to Cambrian seawater sulphate (25–35‰) and Sr isotope compositions ( 87 Sr/ 86 Sr = 0.706905 to 0.707485). These results are consistent with barite having formed from fluid–fluid mixing between Cambrian seawater and VMS-related hydrothermal fluids. The 87 Sr/ 86 Sr values in the barite are lower than mid-Cambrian seawater, which suggests that some of the Sr was derived from the underlying Neoproterozoic basement. Fluid inclusions in bladed barite are low-salinity, CO 2 -rich inclusions with homogenization temperatures between 245°–250 °C, and average salinity of 1.2 wt.% NaCl equivalent. Estimated minimum trapping pressures of between 1.7 to 2.0 kbars were calculated from aqueous–carbonic fluid inclusion assemblages. The fluid inclusion results reflect regional metamorphic reequilibration during younger Silurian regional metamorphism, rather than primary fluid signatures, despite the preservation of primary barite and fluid inclusion textures. These results illustrate that barite in VMS deposits records the physicochemical processes associated with VMS formation and the sources of fluids in ancient VMS deposits, as well as seawater sulphate and basement isotopic compositions. The results herein are not only relevant for the Lemarchant deposit but also for other barite-rich VMS deposits globally. Article in Journal/Newspaper Newfoundland Canadian Science Publishing Canada Canadian Journal of Earth Sciences 57 1 133 166 |
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Canadian Science Publishing |
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English |
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Barite in the approximately 513 Ma Lemarchant volcanogenic massive sulphide (VMS) deposit, Newfoundland, consists of granular and bladed barite intimately associated with mineralization. Regardless of type, the composition of barite is homogeneous at bulk rock and mineral scale containing predominantly Ba, S, and Sr, with minor Ca and Na. The barite has homogeneous sulphur isotope compositions (δ 34 S mean = 27‰), similar to Cambrian seawater sulphate (25–35‰) and Sr isotope compositions ( 87 Sr/ 86 Sr = 0.706905 to 0.707485). These results are consistent with barite having formed from fluid–fluid mixing between Cambrian seawater and VMS-related hydrothermal fluids. The 87 Sr/ 86 Sr values in the barite are lower than mid-Cambrian seawater, which suggests that some of the Sr was derived from the underlying Neoproterozoic basement. Fluid inclusions in bladed barite are low-salinity, CO 2 -rich inclusions with homogenization temperatures between 245°–250 °C, and average salinity of 1.2 wt.% NaCl equivalent. Estimated minimum trapping pressures of between 1.7 to 2.0 kbars were calculated from aqueous–carbonic fluid inclusion assemblages. The fluid inclusion results reflect regional metamorphic reequilibration during younger Silurian regional metamorphism, rather than primary fluid signatures, despite the preservation of primary barite and fluid inclusion textures. These results illustrate that barite in VMS deposits records the physicochemical processes associated with VMS formation and the sources of fluids in ancient VMS deposits, as well as seawater sulphate and basement isotopic compositions. The results herein are not only relevant for the Lemarchant deposit but also for other barite-rich VMS deposits globally. |
format |
Article in Journal/Newspaper |
author |
Lajoie, Marie-Ève Piercey, Stephen J. Conliffe, James Layton-Matthews, Daniel |
spellingShingle |
Lajoie, Marie-Ève Piercey, Stephen J. Conliffe, James Layton-Matthews, Daniel Geology, mineralogy, S and Sr isotope geochemistry, and fluid inclusion analysis of barite associated with the Lemarchant Zn–Pb–Cu–Ag–Au-rich volcanogenic massive sulphide deposit, Newfoundland, Canada |
author_facet |
Lajoie, Marie-Ève Piercey, Stephen J. Conliffe, James Layton-Matthews, Daniel |
author_sort |
Lajoie, Marie-Ève |
title |
Geology, mineralogy, S and Sr isotope geochemistry, and fluid inclusion analysis of barite associated with the Lemarchant Zn–Pb–Cu–Ag–Au-rich volcanogenic massive sulphide deposit, Newfoundland, Canada |
title_short |
Geology, mineralogy, S and Sr isotope geochemistry, and fluid inclusion analysis of barite associated with the Lemarchant Zn–Pb–Cu–Ag–Au-rich volcanogenic massive sulphide deposit, Newfoundland, Canada |
title_full |
Geology, mineralogy, S and Sr isotope geochemistry, and fluid inclusion analysis of barite associated with the Lemarchant Zn–Pb–Cu–Ag–Au-rich volcanogenic massive sulphide deposit, Newfoundland, Canada |
title_fullStr |
Geology, mineralogy, S and Sr isotope geochemistry, and fluid inclusion analysis of barite associated with the Lemarchant Zn–Pb–Cu–Ag–Au-rich volcanogenic massive sulphide deposit, Newfoundland, Canada |
title_full_unstemmed |
Geology, mineralogy, S and Sr isotope geochemistry, and fluid inclusion analysis of barite associated with the Lemarchant Zn–Pb–Cu–Ag–Au-rich volcanogenic massive sulphide deposit, Newfoundland, Canada |
title_sort |
geology, mineralogy, s and sr isotope geochemistry, and fluid inclusion analysis of barite associated with the lemarchant zn–pb–cu–ag–au-rich volcanogenic massive sulphide deposit, newfoundland, canada |
publisher |
Canadian Science Publishing |
publishDate |
2020 |
url |
http://dx.doi.org/10.1139/cjes-2018-0161 http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjes-2018-0161 http://www.nrcresearchpress.com/doi/pdf/10.1139/cjes-2018-0161 |
geographic |
Canada |
geographic_facet |
Canada |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
Canadian Journal of Earth Sciences volume 57, issue 1, page 133-166 ISSN 0008-4077 1480-3313 |
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http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/cjes-2018-0161 |
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Canadian Journal of Earth Sciences |
container_volume |
57 |
container_issue |
1 |
container_start_page |
133 |
op_container_end_page |
166 |
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1809923098283081728 |