%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Balan, Etienne
%A De Villiers, J.P.R.
%A Eeckhout, S.G.
%A Glatzel, P.
%A Toplis, M. J.
%A Fritsch, Emmanuel
%A Allard, T.
%A Galoisy, L.
%A Calas, G.
%T The oxidation state of vanadium in titanomagnetite from layered basic intrusions
%D 2006
%L PAR00000902
%G ENG
%J American Mineralogist
%@ 0003-004X
%K trace elements ; XAS XANES ; igneous petrology ; new technique
%K AFRIQUE DU SUD
%M CC:0002378135-0027
%N 5-6
%P 953-956
%R 10.2138/am.2006.2192
%U https://www.documentation.ird.fr/hor/PAR00000902
%> https://www.documentation.ird.fr/intranet/publi/depot/2011-11-09/010053287.pdf
%V 91
%W Horizon (IRD)
%X The redox conditions prevailing during the formation of vanadiferous titanomagnetites from three layered intrusions (Bushveld; Koillismaa; Skaergaard) have been estimated from the valence state of vanadium using synchrotron X-ray absorption near edge structure spectroscopy (XANES). Using a high energy-resolution X-ray emission spectrometer, we show that vanadium occurs mostly as V3+, with minor V4+. The most concentrated samples (up to 2.4 Wt% V2O3) contain approximately 10% of vanadium as V4+. Both V3+ and V4+ occur in the octahedral site of the spinel structure. Considering the low magnetite/melt V4+ partition coefficients, this suggests that vanadium ores crystallized under specific oxidizing conditions.
%$ 064