Valence state partitioning of V between pyroxene-melt: Effects of pyroxene and melt composition, and direct determination of V valence states by XANES. Application to Martian basalt QUE 94201 composition

Journal Article · Tue Jan 13 04:00:00 EST 2009 · Meteorit. Planet Sci.

OSTI ID:1006949

Karner, J M; Papike, J J; Sutton, S R; Shearer, C K; Burger, P; McKay, G; Le, L ^[1]

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1. UNM

Experiments on a Martian basalt composition show that D{sub V} augite/melt is greater than D{sub V} pigeonite/melt in samples equilibrated under the same fO{sub 2} conditions. This increase is due to the increased availability of elements for coupled substitution with the V{sup 3+} or V{sup 4+} ions, namely Al and Na. for this bulk composition, both Al and Na are higher in concentration in augite compared with pigeonite; therefore more V can enter augite than pigeonite. Direct valence state determination by XANES shows that the V{sup 3+} and V{sup 4+} are the main V species in the melt at fO{sub 2} conditions of IW-1 to IW+3.5, whereas pyroxene grains at IW-1, IW, and IW+1 contain mostly V{sup 3+}. This confirms the idea that V{sup 3+} is more compatible in pyroxene than V{sup 4+}. The Xanes data also indicates that a small percentage of V{sup 2+} may exist in melt and pyroxene at IW-1. The similar valence of V in glass and pyroxene at IW-1 suggests that V{sup 2+} and V{sup 3+} may have similar compatibilities in pyroxene.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: USDOE
• OSTI ID: 1006949
• Journal Information: Meteorit. Planet Sci., Journal Name: Meteorit. Planet Sci. Journal Issue: (8) ; 2008 Vol. 43; ISSN 1086-9379
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

58 GEOSCIENCES
AVAILABILITY
BASALT
ELEMENTS
GLASS
IONS
SILICATE MINERALS
VALENCE