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Micro-XANES Measurements on Experimental Spinels and the Oxidation State of Vanadium in Spinel-Melt PairsSpinel can be a significant host phase for V as well as other transition metals such as Ni and Co. However, vanadium has multiple oxidation states V(2+), V(3+), V(4+) or V(5+) at oxygen fugacities relevant to natural systems. We do know that D(V) spinel/melt is correlated with V and TiO2 content and fO2, but the uncertainty of the oxidation state under the range of natural conditions has made elusive a thorough understanding of D(V) spinel/melt. For example, V(3+) is likely to be stable in spinels, based on exchange with Al in experiments in the CaO-MgO-Al2O3-SiO2 system. On the other hand, it has been argued that V(4+) will be stable across the range of natural oxygen fugacities in nature. In order to gain a better understanding of D(V) spinel/melt we have equilibrated spinel-melt pairs at controlled oxygen fugacities, between HM to NNO, where V is present in the spinel at natural levels (approx. 300 ppm V). These spinel-melt pairs were analyzed using micro-XANES at the Advanced Photon Source at Argonne National Laboratory. The new results will be used together with spinel compositional data (Ti, V content) and oxygen fugacity, to unravel the effects of these variables on D(V) spinel/melt.
Document ID
20040085449
Document Type
Conference Paper
Authors
Righter, K.
(NASA Johnson Space Center Houston, TX, United States)
Sutton, S.R.
(Chicago Univ. Chicago, IL, United States)
Newville, M.
(Chicago Univ. Chicago, IL, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2004
Publication Information
Publication: Workshop on Oxygen in the Terrestrial Planets
Subject Category
Geosciences (General)
Distribution Limits
Public
Copyright
Public Use Permitted.
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