Piccoli, F.; Hermann, J.; Pettke, T.; Connolly, J.A.D.; Kempf, E. D.; Vieira Duarte, J. F. (2019). Subducting serpentinites release reduced, not oxidized, aqueous fluids. Scientific reports, 9(1) Springer Nature 10.1038/s41598-019-55944-8
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The observation that primitive arc magmas are more oxidized than mid-ocean-ridge basalts has led
to the paradigm that slab-derived fluids carry SO2 and CO2 that metasomatize and oxidize the subarc
mantle wedge. We combine petrography and thermodynamic modelling to quantify the oxygen
fugacity (fO2) and speciation of the fluids generated by serpentinite dehydration during subduction.
Silicate-magnetite assemblages maintain fO2 conditions similar to the quartz-fayalite-magnetite (QFM)
buffer at fore-arc conditions. Sulphides are stable under such conditions and aqueous fluids contain
minor S. At sub-arc depth, dehydration occurs under more reducing conditions producing aqueous fluids
carrying H2S. This finding brings into question current models in which serpentinite-derived fluids are
the cause of oxidized arc magmatism and has major implications for the global volatile cycle, as well as
for redox processes controlling subduction zone geodynamics.
Item Type: |
Journal Article (Original Article) |
|---|---|
Division/Institute: |
08 Faculty of Science > Institute of Geological Sciences 08 Faculty of Science > Institute of Geological Sciences > Rock-Water Interaction |
UniBE Contributor: |
Piccoli, Francesca, Hermann, Jörg, Pettke, Thomas, Kempf, Elias Dominik, Vieira Duarte, Joana Filipa |
Subjects: |
500 Science > 550 Earth sciences & geology |
ISSN: |
2045-2322 |
Publisher: |
Springer Nature |
Funders: |
[UNSPECIFIED] Swiss National Science Foundation grants No. 200021_172688 to T.P. ; [UNSPECIFIED] Swiss National Science Foundation grants No. 200021_169062 to J.H. |
Language: |
English |
Submitter: |
Thomas Pettke |
Date Deposited: |
29 Jan 2020 16:09 |
Last Modified: |
05 Dec 2022 15:36 |
Publisher DOI: |
10.1038/s41598-019-55944-8 |
BORIS DOI: |
10.7892/boris.139262 |
URI: |
https://boris.unibe.ch/id/eprint/139262 |
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