Lattice preferred orientation of olivine aggregates deformed in simple shear
Article Abstract:
In a simple-shear deformation experiment, the lattice preferred orientation (LPO) of olivine with the axis parallel to the direction of flow was observed only if the highly deformed upper-mantle rocks's deformation is large. In smaller strains, LPO rotated with respect to the direction of flow. Thus the sense of shear in the asthenosphere and the mechanism of the rifting can be determined from seismic anisotrophy. The determination of the sense of shear from the asymmetrical LPO is possible only for large strains with significant dynamic recrystallization.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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Plastic deformation of silicate spinel under the transition-zone conditions of the Earth's mantle
Article Abstract:
The results of high-pressure, high-temperature, large-strain shear deformation experiments on ring-woodite having different grain sizes is reported. A new experimental method was used, with a starting material of synthetic olivine aggregate with Fe/(Fe+Mg)=0.4, synthesized from an oxide mixture. There was evidence of dislocation creep with dislocation structures similar to those seen in oxide and germanate spinels, in coarse-grained samples, although a fine grained sample showed evidence of grain-size-sensitive creep.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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Determination of olivine cooling rates from metal-cation ordering
Article Abstract:
A method based on in situ neutron-diffraction measurements of cation ordering is used to determine the kinetics and thermodynamics of metal partitioning in olivines. The ordering of metal cations in two structurally different octahedral sites in olivine crystals enables the study of the thermal history of rocks. The rate of cooling of olivine can be derived from the room-temperature structure of the olivine. The method can be used to determine the cooling rates of rapidly-cooling rock-forming olivines.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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