No significant boron in the hydrated mantle of most subducting slabs

McCaig, A. M., Titarenko, S. S., Savov, I. P., Cliff, R. A., Banks, D., Boyce, A. and Agostini, S. (2018) No significant boron in the hydrated mantle of most subducting slabs. Nature Communications, 9(1), 4602. (doi: 10.1038/s41467-018-07064-6) (PMID:30389930) (PMCID:PMC6214984)

[img]
Preview
Text
173344.pdf - Published Version
Available under License Creative Commons Attribution.

2MB

Abstract

Boron has become the principle proxy for the release of seawater-derived fluids into arc volcanics, linked to cross-arc variations in boron content and isotopic ratio. Because all ocean floor serpentinites so far analysed are strongly enriched in boron, it is generally assumed that if the uppermost slab mantle is hydrated, it will also be enriched in boron. Here we present the first measurements of boron and boron isotopes in fast-spread oceanic gabbros in the Pacific, showing strong take-up of seawater-derived boron during alteration. We show that in one-pass hydration of the upper mantle, as proposed for bend fault serpentinisation, boron will not reach the hydrated slab mantle. Only prolonged hydrothermal circulation, for example in a long-lived transform fault, can add significant boron to the slab mantle. We conclude that hydrated mantle in subducting slabs will only rarely contribute to boron enrichment in arc volcanics, or to deep mantle recycling.

Item Type:Articles
Additional Information:This work was supported by NERC grant NE/K011030/1 to A.M.C.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Boyce, Professor Adrian
Authors: McCaig, A. M., Titarenko, S. S., Savov, I. P., Cliff, R. A., Banks, D., Boyce, A., and Agostini, S.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Nature Communications
Publisher:Nature Publishing Group
ISSN:2041-1723
ISSN (Online):2041-1723
Copyright Holders:Copyright © 2018 The Authors
First Published:First published in Nature Communications 9(1):4602
Publisher Policy:Reproduced under a Creative Commons License

University Staff: Request a correction | Enlighten Editors: Update this record