Uncovering and quantifying the subduction zone sulfur cycle from the slab perspective

Li JL, Schwarzenbach EM, John T, Ague JJ, Huang F, Gao J, Klemd R, Whitehouse MJ, Wang XS (2020)

Publication Type: Journal article

Publication year: 2020

Journal

Nature Communications Nature Publishing Group: Nature Communications

Book Volume: 11

Article Number: 514

Journal Issue: 1

DOI: 10.1038/s41467-019-14110-4

Abstract

Sulfur belongs among H2O, CO2, and Cl as one of the key volatiles in Earth’s chemical cycles. High oxygen fugacity, sulfur concentration, and δ34S values in volcanic arc rocks have been attributed to significant sulfate addition by slab fluids. However, sulfur speciation, flux, and isotope composition in slab-dehydrated fluids remain unclear. Here, we use high-pressure rocks and enclosed veins to provide direct constraints on subduction zone sulfur recycling for a typical oceanic lithosphere. Textural and thermodynamic evidence indicates the predominance of reduced sulfur species in slab fluids; those derived from metasediments, altered oceanic crust, and serpentinite have δ34S values of approximately −8‰, −1‰, and +8‰, respectively. Mass-balance calculations demonstrate that 6.4% (up to 20% maximum) of total subducted sulfur is released between 30–230 km depth, and the predominant sulfur loss takes place at 70–100 km with a net δ34S composition of −2.5 ± 3‰. We conclude that modest slab-to-wedge sulfur transport occurs, but that slab-derived fluids provide negligible sulfate to oxidize the sub-arc mantle and cannot deliver 34S-enriched sulfur to produce the positive δ34S signature in arc settings. Most sulfur has negative δ34S and is subducted into the deep mantle, which could cause a long-term increase in the δ34S of Earth surface reservoirs.

Authors with CRIS profile

Reiner Klemd Professur für Geochemie von Lagerstätten

Involved external institutions

Chinese Academy of Sciences (CAS) / 中国科学院 CN China (CN) Freie Universität Berlin DE Germany (DE) Yale University US United States (USA) (US) Rensselaer Polytechnic Institute (RPI) US United States (USA) (US) Swedish Museum of Natural History SE Sweden (SE)

How to cite

APA:

Li, J.L., Schwarzenbach, E.M., John, T., Ague, J.J., Huang, F., Gao, J.,... Wang, X.S. (2020). Uncovering and quantifying the subduction zone sulfur cycle from the slab perspective. Nature Communications, 11(1). https://dx.doi.org/10.1038/s41467-019-14110-4

MLA:

Li, Ji Lei, et al. "Uncovering and quantifying the subduction zone sulfur cycle from the slab perspective." Nature Communications 11.1 (2020).

BibTeX: Download