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Incorporation of ferric iron in CaSiO3 perovskite at high pressure

Published online by Cambridge University Press:  05 July 2018

Zhongwu Wang  and
T. Yagi
Zhongwu Wang
Affiliation:
Institute for Solid State Physics, The University of Tokyo, Roppongi, Tokyo 106, Japan GEMOC, School of Earth Sciences, Macquarie University, Sydney 2109, Australia
T. Yagi
Affiliation:
GEMOC, School of Earth Sciences, Macquarie University, Sydney 2109, Australia
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Abstract

Synthetic andradite (Ca3Fe2Si3O12) has been compressed to loading pressures >21 GPa and heated to ∼1000°C by a YAG laser in a Diamond Anvil Cell (DAC). After quenching to room temperature, X-ray diffraction of the sample, still held at 21 GPa, showed that andradite had transformed to a cubic perovskite type polymorph with a = 3.460(4) Å. Upon decompression the perovskite phase transformed into an amorphous phase. The density of the perovskite polymorph (Ca3Fe2Si3O12) is ∼13.6% greater than that of isochemical andradite at 21 GPa. Ferric iron replaces Ca2+ and Si4+ in the perovskite structure (Fe3+ + Fe3+ = Si4+ + Ca2+), giving a formula unit: (Ca,Fe3+)(Si,Fe3+)O3. The new Fe3+-rich Ca-perovskite may provide new insight into the controls on the electrical conductivity of the lower mantle.

Keywords

andraditehigh pressureX-ray diffractionperovskitelower mantle
Type
Letter
Information
Mineralogical Magazine , Volume 62 , Issue 5 , October 1998 , pp. 719 - 723
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1998

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References

Harris, J., Hutchison, M.T., Hursthouse, M., Light, M. and Harte, B. (1997) A new tetragonal silicate mineral occurring as inclusions in lower mantle diamonds. Nature, 387, 486–9.CrossRefGoogle Scholar
Hishinuma, T. and Yagi, T. (1994) Surface tension of iron hydride formed by the reaction of iron silicate water under pressure. Proc. Japan Acad., 70, Ser B, 71–6.CrossRefGoogle Scholar
Li, X. and Jeanloz, R.L. (1990) Laboratory studies of the electrical conductivity of silicate perovskite at high pressure and high temperature. J. Geophys. Res., 95, 5067–87.CrossRefGoogle Scholar
Liu, L-G. and Ringwood, A.E. (1975) Synthesis of a perovskite type polymorph of CaSiO3 . Earth Plan. Sci. Lett., 28, 209–11.CrossRefGoogle Scholar
Mao, H.K., Bell, P.M., Shaner, J.W. and Steinberg, D.J. (1978) Specific volume measurements of Cu, Mo, Pd, and Ag calibration of the ruby R1 fluorescence pressure gauge from 0.05 to 1 Mbar. J. Appl. Phys., 49, 3276–87.CrossRefGoogle Scholar
McCammon, C. (1997) Perovskite as a possible sink for ferric iron in the lower mantle. Nature, 387, 694–6.CrossRefGoogle Scholar
McCammon, C., Hutchinson, M. and Harris, J.W. (1997) Ferric iron content of mineral inclusions in diamonds from Sao Luiz: A view into the lower mantle. Science, 278, 434–6.CrossRefGoogle Scholar
Poirier, J.B. and Peyronneau, J. (1992) Experimental determination of the electrical conductivity of the material of the Earth's lower mantle. In High pressure research in mineral Physics: Application to Earth and Planetary Sciences, (Syono, Y. and Maghnani, M.H., eds. ), 77–78, Tena Scientific Tokyo.Google Scholar
Tamai, H. and Yagi, T. (1989) High pressure and high temperatur e phase relations in CaSiO3 and CaMgSi2O6 and elasticity of perovskite-type CaSiO3 . Phys. Earth Planet. Inters., 54, 370–7.CrossRefGoogle Scholar
Wood, B.J. and Rubie, D.C. (1996) The Effect of Alumina on phase transformations at the 660- kilometre discontinuity from Fe-Mg partitioning experiments. Science, 273, 1522–4.CrossRefGoogle Scholar
Woodland, A.B and O’Neill, H.St.C. (1995) Phase relation between Ca3Fe3+Si3O12 -Fe2+ 3Fe3+ 2Si3O12 garnet and CaFeSi2O6 pyroxene solid solutions. Contrib. Mineral. Petrol., 121, 7–98.CrossRefGoogle Scholar
Yagi, T., Kusanagi, S., Tsuchida, Y. and Fukai, Y. (1989) Isothermal compression and stability of perovskite-type CaSiO3 . Proc. Japan Acad., 65, Ser. B, 129–32.CrossRefGoogle Scholar