The oxidation states of niobium and tantalum in mantle melts
The oxidation states of niobium and tantalum in mantle melts
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DOI：
10.1016/j.chemgeo.2012.09.002
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发表时间：
2012-11-10
期刊：
影响因子：
3.9
通讯作者：
Cibin, Giannantonio
中科院分区：
文献类型：
--
作者：
Burnham, Antony D.;Berry, Andrew J.;Cibin, Giannantonio
Niobium K-edge and tantalum L-m-edge XANES spectra were recorded for silicate glasses quenched from melts equilibrated at oxygen fugacities (in log units relative to the iron-wustite buffer) ranging from IW + 6.7 to IW 43 at 1400-1650 degrees C and atmospheric pressure to 15 GPa. Niobium and tantalum were found to occur exclusively as Nb5+ and Ta5+. This suggests that changes in oxidation state do not contribute to the fractionation of Nb from Ta in arc settings or the generation of the hidden Nb-rich reservoir that is necessary to explain the deviation of the Nb/Ta ratio of the bulk silicate Earth from the chondritic value. (C) 2012 Elsevier B.V. All rights reserved.
