Assessing sulfur redox state and distribution in abyssal serpentinites using XANES spectroscopy
dc.contributor.author
Debret, Baptiste
dc.contributor.author
Andreani, Muriel
dc.contributor.author
Delacour, Adélie
dc.contributor.author
Rouméjon, Stéphane
dc.contributor.author
Trcera, Nicolas
dc.contributor.author
EIMF (Edinburgh Ion Microprobe Facility)
dc.contributor.author
Williams, Helen
dc.date.accessioned
2017-11-10T14:25:48Z
dc.date.available
2017-10-06T03:42:33Z
dc.date.available
2017-11-10T14:24:27Z
dc.date.available
2017-06-12T20:43:22Z
dc.date.available
2017-11-10T14:25:48Z
dc.date.issued
2017-05-15
dc.identifier.issn
0012-821X
dc.identifier.issn
1385-013X
dc.identifier.other
10.1016/j.eps1.2017.02.029
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/207239
dc.identifier.doi
10.3929/ethz-b-000191803
dc.description.abstract
Sulfur is one of the main redox sensitive and volatile elements involved in chemical transfers between earth surface and the deep mantle. At mid-oceanic ridges, sulfur cycle is highly influenced by serpentinite formation which acts as a sink of sulfur under various oxidation states (S2−, S−, S0 and S6+). Sulfur sequestration in serpentinites is usually attributed to the crystallization of secondary minerals, such as sulfides (e.g. pyrite, pyrrhotite) or sulfates (e.g. anhydrite). However, the role of serpentine minerals as potential sulfur carriers is not constrained. We investigate the distribution and redox state of sulfur at micro-scale combining in situ spectroscopic (X-ray absorption near-edge structure: XANES) and geochemical (SIMS) measurements in abyssal serpentinites from the SWIR (South West Indian Ridge), the Rainbow and the MARK (Mid-Atlantic Ridge, Kane Fracture Zone) areas. These serpentinites are formed in different tectono-metamorphic settings and provide a meaningful database to understand the fate of sulfur during seafloor serpentinization. XANES spectra of serpentinite powders show that the sulfur budget of the studied samples is dominated by oxidized sulfur (S6+/∑S=0.6–1) although sulfate micro-phases, such as barite and anhydrite, are absent. Indeed, μ-XANES analyses of mesh, bastite and antigorite veins in thin sections and of serpentine grains rather suggest the presence of S6+ ions incorporated into serpentine minerals. The structural incorporation of S in serpentine minerals is also supported by X-ray fluorescence mapping revealing large areas (1600 μm2) of serpentinite where S is homogeneously distributed. Our observations show that serpentine minerals can incorporate high S concentrations, from 140 to 1350 ppm, and that this can account for 60 to 100% of the sulfur budget of abyssal serpentinites. Serpentine minerals thus play an important role in S exchanges between the hydrosphere and the mantle at mid-oceanic ridges and may participate to S recycling in subduction zones.
en_US
dc.format
application/pdf
dc.language.iso
en
en_US
dc.publisher
Elsevier
en_US
dc.rights.uri
http://creativecommons.org/licenses/by/4.0/
dc.subject
Mid-oceanic ridge
en_US
dc.subject
Serpentinite
en_US
dc.subject
Sulfate
en_US
dc.subject
Sulfide
en_US
dc.subject
Sulfur sequestration
en_US
dc.title
Assessing sulfur redox state and distribution in abyssal serpentinites using XANES spectroscopy
en_US
dc.type
Journal Article
dc.rights.license
Creative Commons Attribution 4.0 International
dc.date.published
2017-03-16
ethz.journal.title
Earth and Planetary Science Letters
ethz.journal.volume
466
en_US
ethz.journal.abbreviated
Earth Planet. Sci. Lett.
ethz.pages.start
1
en_US
ethz.pages.end
11
en_US
ethz.version.deposit
publishedVersion
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Amsterdam
en_US
ethz.publication.status
published
en_US
ethz.date.deposited
2017-06-12T20:43:42Z
ethz.source
WOS
ethz.source
ECIT
ethz.identifier.importid
imp59365563d73cf42074
ethz.ecitpid
pub:193208
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2017-11-13T07:56:50Z
ethz.rosetta.lastUpdated
2022-03-28T18:03:03Z
ethz.rosetta.versionExported
true
dc.identifier.olduri
http://hdl.handle.net/20.500.11850/130205
dc.identifier.olduri
http://hdl.handle.net/20.500.11850/191803
ethz.COinS
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