Deformation and texture development in CaIrO[subscript 3] post-perovskite

Journal Article · Mon Apr 21 04:00:00 EDT 2008 · Earth Planet. Sci. Lett.

DOI:https://doi.org/10.1016/j.epsl.2008.02.005· OSTI ID:1006562

Miyagi, Lowell; Nishiyama, Norimasa; Wang, Yanbin; Kubo, Atsushi; West, Don V; Cava, Robert J; Duffy, Thomas S; Wenk, Hans-Rudolf ^[1]

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1. UCB

At near ambient conditions, CaIrO{sub 3} is isostructural with the high-pressure polymorph MgSiO{sub 3} 'post-perovskite' (pPv). MgSiO{sub 3} pPv is thought to be a major phase in the earth's lowermost mantle. CaIrO{sub 3} can thus serve as an analog for studying deformation of the pPv phase under conditions achievable with a multi-anvil deformation apparatus. Here we study the rheologic behavior of CaIrO{sub 3} pPv at a variety of pressure and temperature conditions from 2 GPa to 6 GPa and 300 K to 1300 K and various strain rates. Sintered, polycrystalline CaIrO{sub 3} pPv, cylindrical in shape, was deformed in the D-DIA multi-anvil press in several shortening cycles up to 20% axial strain at each temperature and pressure. Shortening cycles were followed by lengthening back to 0% strain. Quantitative texture information was obtained using in-situ synchrotron X-ray diffraction and the Rietveld method to analyze images. In all cases we find that (010) lattice planes align perpendicular to the compression direction upon shortening, and that there is little change in texture with temperature or pressure. This texture pattern is consistent with slip on (010)[100]. The texture observed here is different from that produced in room temperature diamond anvil cell (DAC) experiments on MgGeO{sub 3} and MgSiO{sub 3} pPv which both display textures of (100) and {l_brace}110{r_brace} lattice planes at high angles to the compression direction. This implies that CaIrO{sub 3} pPv may not be a good analog for the plastic behavior of MgSiO{sub 3} pPv.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: USDOE
• OSTI ID: 1006562
• Journal Information: Earth Planet. Sci. Lett., Journal Name: Earth Planet. Sci. Lett. Journal Issue: (3-4) ; 04, 2008 Vol. 268; ISSN 0012-821X; ISSN EPSLA2
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

58 GEOSCIENCES
BEHAVIOR
CALCIUM OXIDES
COMPRESSION
DEFORMATION
DIAMONDS
EARTH MANTLE
IRIDIUM OXIDES
MAGNESIUM SILICATES
PLASTICITY
PRESSURE RANGE MEGA PA 10-100
RHEOLOGY
SHAPE
SLIP
STRAIN RATE
STRAINS
SYNCHROTRON RADIATION
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
TEXTURE
X-RAY DIFFRACTION