Mobilization of isotopically heavy sulfur during serpentinite subduction

Schwarzenbach, Esther M.; Dragovic, Besim; Codillo, Emmanuel A.; Streicher, Linus; Scicchitano, Maria Rosa; Wiechert, Uwe; Klein, Frieder; Marschall, Horst R.; Scambelluri, Marco

doi:10.1126/sciadv.adn0641

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Mobilization of isotopically heavy sulfur during serpentinite subduction

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Schwarzenbach, Esther M. ORCID University of Fribourg
Dragovic, Besim ORCID University of South Carolina, Columbia, SC, USA
Codillo, Emmanuel A. ORCID Carnegie Institution for Science, Washington DC, USA
Streicher, Linus ORCID Freie Universität Berlin, Germany
Scicchitano, Maria Rosa ORCID Deutsches GeoForschungsZentrum GFZ, Potsdam, Germany
Wiechert, Uwe Freie Universität Berlin, Germany
Klein, Frieder ORCID Woods Hole Oceanographic Institution, Woods Hole, MA, USA
Marschall, Horst R. ORCID Goethe Universität, Frankfurt am Main, Germany
Scambelluri, Marco ORCID University of Genoa, Italy

2024

Published in:

Science Advances. - American Association for the Advancement of Science (AAAS). - 2024, vol. 10, no. 32, p. 1-15

English Primitive arc magmas are more oxidized and enriched in 34S compared to mid-ocean ridge basalts (MORB). These findings have been linked to the addition of slab-derived volatiles, particularly sulfate, to arc magmas. However, the oxidation state of sulfur in slab fluids and the mechanisms of S transfer in the slab remain inconclusive. Juxtaposed serpentinite and eclogitic metagabbro from the Voltri Massif (Italy) provide evidence for S mobilization and associated redox processes during infiltration of fluids. Using bulk rock and in situ δ34S measurements, combined with thermodynamic calculations, we document the transfer of HS--dominated, 34S-enriched fluids in equilibrium with serpentinite into adjacent metagabbro. We argue that the process documented in this study is pervasive along the subduction interface and infer that subsequent melting of such reacted slab-mantle-interface rocks could produce melts that display the characteristic fO2 and sulfur isotope signatures of arc magmas worldwide.

Faculty

Faculté des sciences et de médecine

Department

Département de Géosciences

Language