Experimental determination of activities in Fe-Mg olivine at 1400 K

Nathan M. Wiser; Bernard J. Wood

doi:10.1007/BF00307333

Experimental determination of activities in Fe-Mg olivine at 1400 K

Nathan M. Wiser^*, Bernard J. Wood

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

81 Citations (Scopus)

Abstract

The exchage equilibrium {Mathematical expression} has been used to measure activity-composition relations along the olivine join FeSi_0.5O₂-MgSi_0.5O₂ at 1400 K and 1 atm pressure. Equilibrium Fe-Mg partitioning between the two phases was determined by reversing the compositions of olivine coexisting with oxide and matallic iron over the composition range Fo₂₃ to Fo₉₂. A detailed study of the thermodynamic properties of the oxide phase has recently been made by Srečec et al. and we have confirmed their results in the composition range of interest. Application of the oxide data to the exchange equilibrium enables the properties of olivine to be determined. Within experimental uncertainly (Fe, Mg)Si_0.5O₂ olivine can, at 1400 K, be treated as a symmetric solution with W_Fe-Mg^o1 of 3.7±0.8 kJ/mol. The data permit the presence of only very slight asymmetry in the series. The data do not support recent assertions that olivine is highly non-ideal (W≈10 kJ/mol) under these conditions.

Original language	English
Pages (from-to)	146-153
Number of pages	8
Journal	Contributions to Mineralogy and Petrology
Volume	108
Issue number	1-2
DOIs	https://doi.org/10.1007/BF00307333
Publication status	Published - Jul 1991

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@article{776fb1a270f04977af207cecffae093d,

title = "Experimental determination of activities in Fe-Mg olivine at 1400 K",

abstract = "The exchage equilibrium {Mathematical expression} has been used to measure activity-composition relations along the olivine join FeSi0.5O2-MgSi0.5O2 at 1400 K and 1 atm pressure. Equilibrium Fe-Mg partitioning between the two phases was determined by reversing the compositions of olivine coexisting with oxide and matallic iron over the composition range Fo23 to Fo92. A detailed study of the thermodynamic properties of the oxide phase has recently been made by Sre{\v c}ec et al. and we have confirmed their results in the composition range of interest. Application of the oxide data to the exchange equilibrium enables the properties of olivine to be determined. Within experimental uncertainly (Fe, Mg)Si0.5O2 olivine can, at 1400 K, be treated as a symmetric solution with WFe-Mgo1 of 3.7±0.8 kJ/mol. The data permit the presence of only very slight asymmetry in the series. The data do not support recent assertions that olivine is highly non-ideal (W≈10 kJ/mol) under these conditions.",

author = "Wiser, {Nathan M.} and Wood, {Bernard J.}",

year = "1991",

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journal = "Contributions to Mineralogy and Petrology",

issn = "0010-7999",

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T1 - Experimental determination of activities in Fe-Mg olivine at 1400 K

AU - Wiser, Nathan M.

AU - Wood, Bernard J.

PY - 1991/7

Y1 - 1991/7

N2 - The exchage equilibrium {Mathematical expression} has been used to measure activity-composition relations along the olivine join FeSi0.5O2-MgSi0.5O2 at 1400 K and 1 atm pressure. Equilibrium Fe-Mg partitioning between the two phases was determined by reversing the compositions of olivine coexisting with oxide and matallic iron over the composition range Fo23 to Fo92. A detailed study of the thermodynamic properties of the oxide phase has recently been made by Srečec et al. and we have confirmed their results in the composition range of interest. Application of the oxide data to the exchange equilibrium enables the properties of olivine to be determined. Within experimental uncertainly (Fe, Mg)Si0.5O2 olivine can, at 1400 K, be treated as a symmetric solution with WFe-Mgo1 of 3.7±0.8 kJ/mol. The data permit the presence of only very slight asymmetry in the series. The data do not support recent assertions that olivine is highly non-ideal (W≈10 kJ/mol) under these conditions.

AB - The exchage equilibrium {Mathematical expression} has been used to measure activity-composition relations along the olivine join FeSi0.5O2-MgSi0.5O2 at 1400 K and 1 atm pressure. Equilibrium Fe-Mg partitioning between the two phases was determined by reversing the compositions of olivine coexisting with oxide and matallic iron over the composition range Fo23 to Fo92. A detailed study of the thermodynamic properties of the oxide phase has recently been made by Srečec et al. and we have confirmed their results in the composition range of interest. Application of the oxide data to the exchange equilibrium enables the properties of olivine to be determined. Within experimental uncertainly (Fe, Mg)Si0.5O2 olivine can, at 1400 K, be treated as a symmetric solution with WFe-Mgo1 of 3.7±0.8 kJ/mol. The data permit the presence of only very slight asymmetry in the series. The data do not support recent assertions that olivine is highly non-ideal (W≈10 kJ/mol) under these conditions.

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JO - Contributions to Mineralogy and Petrology

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Experimental determination of activities in Fe-Mg olivine at 1400 K

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