The effect of fO2 on the partitioning and valence of V and Cr in garnet/melt pairs and the relation to terrestrial mantle V and Cr content

Righter, K.; Sutton, S.R.; Danielson, L. R.; Pando, K.; Schmidt, Gerhard; Yang, Hexiong; Berthet, S.; Newville, Matthew; Choi, Y.; Downs, Robert T.; Malavergne, Valérie

doi:10.2138/am.2011.3690

Cited by 31 publications

(15 citation statements)

References 87 publications

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“…This calibration ( Figure 4b) has yielded good agreement with known V valences ranging from 3 to 5 in natural and synthetic crystals where the valences are known from stoichiometry (Righter et al, 2006(Righter et al, , 2011 (Righter et al, 2011) agree with this calibration within precision. This agreement suggests that valence accuracy is comparable to precision in our measurements of 0.05 (1).…”

Section: (1)supporting

confidence: 56%

“…The energy and intensity systematics of V K XANES spectra were documented by Wong et al (1984). A quantitative approach for determining V valence based on pre-edge peak intensity was developed by Sutton et al (2005) and applied to various earth and planetary materials (e.g., Karner et al, 2006, Karner et al, 2008, Righter et al, 2011, Papike et al, 2013. Cr 2+ /Cr 3+ ratios based on K XANES have also been widely applied (e.g., Sutton et al, 1993, Berry et al, 2004, Berry et al, 2006, Karner et al, 2007a,b, Goodrich et al, 2013.…”

Section: Introductionmentioning

confidence: 99%

“…Few studies have applied multiple, XANES-based oxybarometers to individual mineral grains. Righter et al (2011) applied Cr and V XANES to experimental garnet/melt pairs and found that Cr remains in 3+ valence in garnet across a wide range of fO 2 s (IW-2 to IW+9) whereas V exhibits variable average valence from 2.5 to 3.7. Karner et al (2007a,b) studied Cr and V valence partitioning in pyroxene crystallized from a martian composition melt.…”

Section: Introductionmentioning

confidence: 99%

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Titanium, vanadium and chromium valences in silicates of ungrouped achondrite NWA 7325 and ureilite Y-791538 record highly-reduced origins

Sutton

Goodrich

Wirick

2017

Geochimica et Cosmochimica Acta

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Titanium, Cr, and V valences were determined by applying micro-X-ray Absorption Near Edge Structure (micro-XANES) spectroscopy methods to individual grains of olivine and pyroxene in the ungrouped achondrite NWA 7325 and ureilite Y-791538, as well as to plagioclase in NWA 7325. The advantages of applying multiple, multivalent-element-based oxybarometers to individual grains are (1) the ability to cover the entire oxygen fugacity (fO 2 ) range encountered in nature, and (2) the increased reliability from consistent results for semiindependent fO 2 proxies. fO 2 values were inferred from each mineral valence determination after correcting with available laboratory-experiment-derived, valence-specific partition coefficients to obtain melt valences and then calibrating with the fO 2 values of the relevant equal species proportions points suggested for igneous (primarily basaltic) systems.The resulting olivine and pyroxene valences are highly reduced and similar in the two meteorites with substantial fractions of Cr 2+ , Ti 3+ and V 2+ . The exception is Cr in NWA 7325 pyroxene which is much more oxidized than the Cr in its olivine. Chromium and Ti in plagioclase in NWA 7325 is relatively oxidized (V valence not determined). The anomalously oxidized Cr in NWA 7325 pyroxene may be due to a secondary reheating event that oxidized Cr in the pyroxene without similarly oxidizing Ti and V. Such a separation of the redox couples may be an effect of re-equilibration kinetics, where the valence of Cr would be more rapidly modified. These valences yielded similar mean fO 2 s for the two meteorites; IW-3.1 ± 0.2 for NWA 7325 and IW-2.8 ± 0.2 for Y-791538, consistent with an origin of NWA 7325 in either Mercury or an asteroid that experienced redox conditions similar to those on the ureilite parent body.

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Section: (1)supporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Titanium, vanadium and chromium valences in silicates of ungrouped achondrite NWA 7325 and ureilite Y-791538 record highly-reduced origins

Sutton

Goodrich

Wirick

2017

Geochimica et Cosmochimica Acta

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“…Numerous experimental studies clearly show that Mineral/melt D V are dominantly controlled by fO 2 . Oxygen fugacity controls valence states, coordination numbers, and incorporation mechanism of V in both melts and minerals Mallmann and O'Neill, 2009;Righter et al, 2006;Righter et al, 2011;Shearer et al, 2006a;Shearer et al, 2006b). Furthermore, the addition of other high valence cations (such as Fe 3+ and Ti 4+ ) into the silicate melt can also change the coordination environment of V, and thus its partitioning between minerals and melt (Giuli et al, 2004).…”

Section: Partitioning Of Vanadium Between Minerals and Silicate Meltsmentioning

confidence: 99%

“…Under the P-T-fO 2 conditions of the upper mantle, mineral/melt D V generally decreases in the order of spinel, amphibole, clinopyroxene, garnet, orthopyroxene, and olivine (Adam and Green, 2006;Canil, 1999;Canil, 2004;Karner et al, 2006;Karner et al, 2008;Mallmann and O'Neill, 2009;Righter et al, 2006;Righter et al, 2011). Olivine/melt D V and orthopyroxene/melt D V decrease dramatically from >>1 to <0.01 with increasing valence state from +2 to +5, while V(III) is more compatible than V(II) and V(V) in clinopyroxene (Karner et al, 2008;Mallmann and O'Neill, 2009).…”

Section: Partitioning Of Vanadium Between Minerals and Silicate Meltsmentioning

confidence: 99%