Elasticity of MgSiO3 in the Perovskite Structure

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Science  10 Feb 1989:
Vol. 243, Issue 4892, pp. 787-789
DOI: 10.1126/science.243.4892.787


The single-crystal elastic moduli of MgSiO3 in the perovskite structure, the high-pressure polymorph of MgSiO3 pyroxene, have been determined. The data indicate that a mantle with either pyrolite or pyroxene stoichiometry is compatible with the seismic models appropriate to the earth's lower mantle, provided that the shear modulus of MgSiO3 perovskite exhibits a strong negative temperature derivative. Such a temperature derivative falls outside of the range expected for a well-behaved refractory ceramic and could result if the pressure-temperature regime of the earth's lower mantle is near that required for a ferroelastic phase transformation of the perovskite phase.

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