The origin of S4+ detected in silicate glasses by XANES

Wilke, Max; Jugo, Pedro J.; Klimm, Kevin; Susini, J.; Botcharnikov, Roman E.; Kohn, Simon C.; Janousch, M.

doi:10.2138/am.2008.2765

Cited by 113 publications

(92 citation statements)

References 20 publications

(46 reference statements)

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“…A preliminary attempt to apply this technique to the silicate glass samples of this study resulted in reduction of Ce 4+ to Ce 3+ during exposure to the X-ray beam. This is not necessarily a surprising result as a similar phenomenon has been observed during Eu and Sm L 3 -edge XANES of borate glasses (Shimizugawa et al, 2001) as well as S K-edge XANES of silicate glasses (Wilke et al, 2008). Therefore, in the present study determination of Ce 4+ /Ce 3+ was done using…”

Section: Introduction and Theoretical Backgroundsupporting

confidence: 79%

Cerium oxidation state in silicate melts: Combined f O 2 , temperature and compositional effects

Smythe

Brenan

2015

Geochimica et Cosmochimica Acta

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Section: Introduction and Theoretical Backgroundsupporting

confidence: 79%

Cerium oxidation state in silicate melts: Combined f O 2 , temperature and compositional effects

Smythe

Brenan

2015

Geochimica et Cosmochimica Acta

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“…2, can rapidly convert S 6+ to S 4+ (presumably in an electron exchange reaction with Fe 2+ /Fe 3+ ). It is now believed that previous reports of S 4+ in natural glasses Métrich et al, 2002Métrich et al, , 2003 are an artefact of the analyses (Backnaes et al, 2008;Wilke et al, 2008). S 4+ does, however, occur unambiguously with S 6+ in Fe-free experimental samples prepared in equilibrium with CaSO 4 at 4-16 kbar (Fig.…”

Section: Sulfite Species: Artefact or Realitymentioning

confidence: 86%

“…An alternative technique is S K-edge X-ray absorption near edge structure (XANES) spectroscopy, which has been used to investigate the oxidation state of S in both natural and synthetic glasses (Paris et al, 2001;Fleet, 2005;Fleet et al, 2005;Backnaes et al, 2008;Wilke et al, 2008), including melt inclusions Métrich et al, 2002). Whereas the K-edge energy of most elements is approximately constant for a given oxidation state, the S 2À edge exhibits an anomalously large range e.g., 2469.5 eV for chalcopyrite and 2475.1 eV for MgS (Fleet, 2005).…”

Section: Introductionmentioning

confidence: 99%

The oxidation state of sulfur in synthetic and natural glasses determined by X-ray absorption spectroscopy

Métrich

Berry

O’Neill

et al. 2009

Geochimica et Cosmochimica Acta

142

103

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“…Beam damage has been reported during sulfur XANES analyses, where the effect has been to oxidise sulfur over minutes (Wilke et al, 2008;Métrich et al, 2009;Moussallam et al, 2014).…”

Section: Beam Damagementioning

confidence: 99%

Fe-XANES analyses of Reykjanes Ridge basalts: Implications for oceanic crust's role in the solid Earth oxygen cycle

Shorttle

Moussallam

Hartley

et al. 2015

Earth and Planetary Science Letters

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Editor: T.A. MatherKeywords: mantle f O 2 XANES oxygen mantle heterogeneity pyroxenite The cycling of material from Earth's surface environment into its interior can couple mantle oxidation state to the evolution of the oceans and atmosphere. A major uncertainty in this exchange is whether altered oceanic crust entering subduction zones can carry the oxidised signal it inherits during alteration at the ridge into the deep mantle for long-term storage. Recycled oceanic crust may be entrained into mantle upwellings and melt under ocean islands, creating the potential for basalt chemistry to constrain solid Earth-hydrosphere redox coupling. Numerous independent observations suggest that Iceland contains a significant recycled oceanic crustal component, making it an ideal locality to investigate links between redox proxies and geochemical indices of enrichment. We have interrogated the elemental, isotope and redox geochemistry of basalts from the Reykjanes Ridge, which forms a 700 km transect of the Iceland plume. Over this distance, geophysical and geochemical tracers of plume influence vary dramatically, with the basalts recording both longand short-wavelength heterogeneity in the Iceland plume. We present new high-precision Fe-XANES measurements of Fe 3+ / Fe on a suite of 64 basalt glasses from the Reykjanes Ridge. These basalts exhibit positive correlations between Fe 3+ / Fe and trace element and isotopic signals of enrichment, and become progressively oxidised towards Iceland: fractionation-corrected Fe 3+ / Fe increases by ∼ 0.015 and QFM by ∼ 0.2 log units. We rule out a role for sulfur degassing in creating this trend, and by considering various redox melting processes and metasomatic source enrichment mechanisms, conclude that an intrinsically oxidised component within the Icelandic mantle is required. Given the previous evidence for entrained oceanic crustal material within the Iceland plume, we consider this the most plausible carrier of the oxidised signal.To determine the ferric iron content of the recycled component ([Fe 2 O 3 ] source ) we project observed liquid compositions to an estimate of Fe 2 O 3 in the pure enriched endmember melt, and then apply simple fractional melting models, considering lherzolitic and pyroxenitic source mineralogies, to estimate [Fe 2 O 3 ] (source) content. Propagating uncertainty through these steps, we obtain a range of [Fe 2 O 3 ] (source) for the enriched melts (0.9-1.4 wt%) that is significantly greater than the ferric iron content of typical upper mantle lherzolites. This range of ferric iron contents is consistent with a hybridised lherzolitebasalt (pyroxenite) mantle component. The oxidised signal in enriched Icelandic basalts is therefore potential evidence for seafloor-hydrosphere interaction having oxidised ancient mid-ocean ridge crust, generating a return flux of oxygen into the deep mantle.

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The origin of S4+ detected in silicate glasses by XANES

Cited by 113 publications

References 20 publications

Cerium oxidation state in silicate melts: Combined f O 2 , temperature and compositional effects

Cerium oxidation state in silicate melts: Combined f O 2 , temperature and compositional effects

The oxidation state of sulfur in synthetic and natural glasses determined by X-ray absorption spectroscopy

Fe-XANES analyses of Reykjanes Ridge basalts: Implications for oceanic crust's role in the solid Earth oxygen cycle

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