Iron valency in minerals of xenoliths and redox state of the upper mantle (by Mössbauer spectroscopy data)
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The subjects of the research were mantle xenoliths from Cenozoic alkaline basalts in the Baikalian–Mongolian region. The Mössbauer spectroscopy was used to study iron valence in mineral structures. The mineral compositions were analyzed by microprobe technique. The values of Δlgf O2 for xenoliths is vary: DP: −0.9− (−1.7); TD: −0.9−(−1.8); VP: −0.1–(−0.8); BA: −0.1−(−0.8). p − T equilibrium conditions of mineral association in xenoliths correspond to graphite stability field, Δlgf O2 values evidence of predominance of CO2 and H2O in the mantle fluid. The heterogeneity in redox state corresponds to thermal heterogeneity. The deduced equation allows estimating the value of oxygen fugacity only the data of chemistry and φ Sp.
KeywordsMantle xenoliths Mössbauer spectroscopy Iron valence Oxygen fugacity Redox state
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