Sulfur isotope signatures in the lower crust: A SIMS study on S-rich scapolite of granulites
© 2017 Elsevier B.V. Scapolite is an important reservoir for volatiles in the deep crust and provides unique insights into the S isotope signatures at the mantle/crust interface. Here we document the first scapolite reference material (herein referred to as CB1) for in situ S isotope analysis. The c...
| Main Authors: | , , , , , , , , |
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| Format: | Journal Article |
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Elsevier Science BV
2017
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| Online Access: | http://hdl.handle.net/20.500.11937/72060 |
| _version_ | 1848762648726863872 |
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| author | Hammerli, J. Kemp, A. Barrett, N. Wing, B. Roberts, M. Arculus, R. Boivin, P. Nude, P. Rankenburg, Kai |
| author_facet | Hammerli, J. Kemp, A. Barrett, N. Wing, B. Roberts, M. Arculus, R. Boivin, P. Nude, P. Rankenburg, Kai |
| author_sort | Hammerli, J. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | © 2017 Elsevier B.V. Scapolite is an important reservoir for volatiles in the deep crust and provides unique insights into the S isotope signatures at the mantle/crust interface. Here we document the first scapolite reference material (herein referred to as CB1) for in situ S isotope analysis. The chemical and isotopic composition of this euhedral, S-rich scapolite megacryst was characterized via LA-ICP-MS, EPMA, SIMS, and bulk fluorination gas source isotope ratio mass spectrometry. The CB1 scapolite is isotopically homogeneous and our results show that crystal orientation does not affect in situ S isotope SIMS analysis. This makes CB1 an ideal primary calibration standard for in situ analysis of S isotope ratios (36S/32S,34S/32S and33S/32S) in scapolite. With this reference material in hand, we then applied in situ SIMS analysis of S isotopes for the first time on scapolite in granulite samples from the lower crust/upper mantle. The analysed sample suite comprises rocks from classic granulite xenolith locations in southeastern Australia, as well as a sample from the high-grade suture zone of the Dahomeyides in south-eastern Ghana. The results show that scapolites in the lower crust have d34S values between ~- 0.5 and + 4 (‰ VCDT). These values fall within the range of S isotope signatures present in mantle rocks and provide no evidence for the recycling of seawater-derived S into the lower crust. We propose that scapolite formed during granulite facies metamorphism of igneous cumulates, where S was sourced from precursor igneous sulfides. Sulfur isotope heterogeneities between individual scapolite grains in some of the studied samples may reflect non-uniform S-isotope compositions of igneous S-phases, which precipitated from mantle-derived melt. |
| first_indexed | 2025-11-14T10:50:55Z |
| format | Journal Article |
| id | curtin-20.500.11937-72060 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T10:50:55Z |
| publishDate | 2017 |
| publisher | Elsevier Science BV |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-720602018-12-13T09:34:10Z Sulfur isotope signatures in the lower crust: A SIMS study on S-rich scapolite of granulites Hammerli, J. Kemp, A. Barrett, N. Wing, B. Roberts, M. Arculus, R. Boivin, P. Nude, P. Rankenburg, Kai © 2017 Elsevier B.V. Scapolite is an important reservoir for volatiles in the deep crust and provides unique insights into the S isotope signatures at the mantle/crust interface. Here we document the first scapolite reference material (herein referred to as CB1) for in situ S isotope analysis. The chemical and isotopic composition of this euhedral, S-rich scapolite megacryst was characterized via LA-ICP-MS, EPMA, SIMS, and bulk fluorination gas source isotope ratio mass spectrometry. The CB1 scapolite is isotopically homogeneous and our results show that crystal orientation does not affect in situ S isotope SIMS analysis. This makes CB1 an ideal primary calibration standard for in situ analysis of S isotope ratios (36S/32S,34S/32S and33S/32S) in scapolite. With this reference material in hand, we then applied in situ SIMS analysis of S isotopes for the first time on scapolite in granulite samples from the lower crust/upper mantle. The analysed sample suite comprises rocks from classic granulite xenolith locations in southeastern Australia, as well as a sample from the high-grade suture zone of the Dahomeyides in south-eastern Ghana. The results show that scapolites in the lower crust have d34S values between ~- 0.5 and + 4 (‰ VCDT). These values fall within the range of S isotope signatures present in mantle rocks and provide no evidence for the recycling of seawater-derived S into the lower crust. We propose that scapolite formed during granulite facies metamorphism of igneous cumulates, where S was sourced from precursor igneous sulfides. Sulfur isotope heterogeneities between individual scapolite grains in some of the studied samples may reflect non-uniform S-isotope compositions of igneous S-phases, which precipitated from mantle-derived melt. 2017 Journal Article http://hdl.handle.net/20.500.11937/72060 10.1016/j.chemgeo.2017.02.016 Elsevier Science BV restricted |
| spellingShingle | Hammerli, J. Kemp, A. Barrett, N. Wing, B. Roberts, M. Arculus, R. Boivin, P. Nude, P. Rankenburg, Kai Sulfur isotope signatures in the lower crust: A SIMS study on S-rich scapolite of granulites |
| title | Sulfur isotope signatures in the lower crust: A SIMS study on S-rich scapolite of granulites |
| title_full | Sulfur isotope signatures in the lower crust: A SIMS study on S-rich scapolite of granulites |
| title_fullStr | Sulfur isotope signatures in the lower crust: A SIMS study on S-rich scapolite of granulites |
| title_full_unstemmed | Sulfur isotope signatures in the lower crust: A SIMS study on S-rich scapolite of granulites |
| title_short | Sulfur isotope signatures in the lower crust: A SIMS study on S-rich scapolite of granulites |
| title_sort | sulfur isotope signatures in the lower crust: a sims study on s-rich scapolite of granulites |
| url | http://hdl.handle.net/20.500.11937/72060 |