The elasticity of the upper mantle orthosilicates olivine and garnet to 3 GPa

Webb, Sharon L.

doi:10.1007/bf00223318

Cited by 126 publications

(69 citation statements)

References 21 publications

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“…The first order temperature derivatives have been determined between 295-1500K (Issak, 1992). The first and second order pressure derivatives for olivine were first determined to 3 GPa by Webb (1989). However, a more recent determination to 17 GPa by Abramson et al (1997) has shown that the second order derivative is only necessary for elastic stiffness modulus C 55 .…”

Section: Upper Mantlementioning

confidence: 99%

The Seismic anisotropy of the Earth's mantle: From single crystal to polycrystal

Mainprice¹,

Barruol²,

Ismaı̈l³

2000

Earth's Deep Interior: Mineral Physics and Tomography From the Atomic to the Global Scale

220

172

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The anisotropic single crystal seismic properties are reviewed in the light of recent experimental and theoretical determinations. Although considerable progress has been made on the determination of single crystal properties, data are still lacking, particularly for the temperature derivatives of transition zone and lower mantle phases. The common types of LPO of olivine, opx and cpx are presented together with their associated seismic properties. It is emphasized that simple seismic symmetry pattern of upper mantle rocks are a direct result of the interaction of olivine, opx and cpx. Using the standard structural frame (X lineation, Z pole to foliation) for typical LPOs of olivine, opx and cpx have the maximum Vp parallel to X, in the XZ plane and parallel to Y respectively. Destructive interference occurs between these minerals and hence P-wave anisotropy should be sensitive to the aggregate composition. For shear wave splitting (dVs) typical olivine and opx LPOs result in similar patterns with the maximum dVs in the YZ plane and the fast split shear wave (Vs1) polarized parallel to the foliation. A typical cpx LPO on the other hand produces destructive interference as the max dVs is close to X. By comparison with experiments and numerical simulations, it is estimated that upper mantle samples have an olivine LPO strength which recorded shear strain gamma of between 0.25 and 2.0. Pyrolite and piclogite models are compared with global transverse isotropic models. The slowly reducing P-wave anisotropy in the first 200 km can be explained by a model with constant composition and LPO strength. The sharp decrease in the observed anisotropy in the global models cannot be explained by the transformation of opx to cpx at 300 km, it is proposed that this decrease is due to a reduction in LPO strength from 200 to 350 km at the base of the lithosphere.

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Section: Upper Mantlementioning

confidence: 99%

The Seismic anisotropy of the Earth's mantle: From single crystal to polycrystal

Mainprice¹,

Barruol²,

Ismaı̈l³

2000

Earth's Deep Interior: Mineral Physics and Tomography From the Atomic to the Global Scale

220

172

View full text Add to dashboard Cite

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“…In addition to our results for both cell assemblies, Figure 13 also shows the values of c 22 , c 33 , c 44 , c 55 and c 66 , published by Webb (1989), Zaug et al (1993) and Chen et al (1996). Zaug et al (1993) c 66 this work c 66 Zaug et al (1993) c 55 Zaug et al (1993) c 44 Zaug et al (1993) modulus [GPa] c 33 this work 0 1 2 3 c 33 Zaug et al (1993) Figure 13.…”

Section: San Carlos Olivinementioning

confidence: 51%

“…Elastic moduli of San Carlos olivine versus pressure up to 3 GPa measured in the multi-anvil apparatus MAX80. Published data (Webb, 1989;Zaug et al, 1993;Chen et al, 1996) Chen et al (1996); L, c 55 Chen et al (1996).…”

Section: San Carlos Olivinementioning

confidence: 99%

Simultaneous determination of elastic and structural properties under simulated mantle conditions using multi-anvil device MAX80

Mueller¹,

Schilling²,

Lathe³

2005

Advances in High-Pressure Techniques for Geophysical Applications

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An ultrasonic interferometry high-pressure set-up for elastic wave velocity measurements under simulated Earth's mantle conditions has been developed. A DIA-type multi-anvil apparatus MAX80 permanently located at HASYLAB, Hamburg, Germany for X-ray diffraction (XRD) under in situ condition was equipped for simultaneous ultrasonic measurements. Two of the six anvils were equipped with lithium niobate P-and S-wave transducers of 33.3 MHz natural frequency. The pressure and temperature limits of the high-pressure apparatus were not reduced as a side effect of the modification. The ultrasonic configuration allows all kinds of interferometric measurements with compressional and shear waves. In addition to the classical ultrasonic interferometry the newly developed data transfer function technique (DTF), first described in [J. Phys. Condens. Matter 14 (2002) 11337], is discussed in detail to give the readers the chance to use this valuable and important new method.The results for natural San Carlos olivine up to 3 GPa pressure are compared with published data of several authors. The data for hot-isostatic-pressed anorthite solved discrepancies between published high-pressure and normal-pressure data for polycrystalline anorthite leading to v p ¼ 7.28 km/s, v s ¼ 3.93 km/s at ambient conditions and dv p =dp ¼ 0.027 km/s GPa, dv s =dp ¼ 0.001 km/s GPa. The obtained data sets correspond to published results within the accuracy of the method.As an example for unquenchable phase transitions we measured the elastic wave velocities at the high-pressure clinoenstatite (MgSiO 3 , HCEn) -low-pressure (LCEn) transition at high pressure, high temperature conditions in conjunction with in situ XRD. For ultrasonic interferometry experiments LCEn powder synthesized at ambient pressure was hot-isostatic-pressed at 0.4 GPa and 14008C for 2 h in MAX80 to obtain low-porosity samples. The elastic wave velocities v p and v s of the CEn sample were measured in situ using the classical interferometric technique as well as the recently developed ultrasonic data transfer function (DTF) technique for the elastic wave velocities as a function of pressure at 7008C. To compare the results, v p and v s were measured at 6.7 and 7.5 GPa using both interferometric techniques. The results correspond within the limits of less than 1%.

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“…The elastic constants variation as a function of the olivine Mg# was calculated by linear interpolation between the single-crystal elastic constant tensors measured in laboratory for fayalite, forsterite, and olivine with Mg# of 90, 91, and 93 (Kumazawa and Anderson, 1969;Suzuki et al, 1983;Webb et al, 1989;Isaak et al, 1993;Abramson et al, 1997). For orthopyroxene, clinopyroxene, and garnet, the single crystal elastic tensors of Chai et al (1997a), Collins andBrown (1998), andChai et al (1997b) at ambient pressure (P ) and temperature (T ) were used.…”

Section: Methodsmentioning

confidence: 99%

“…P wave www.solid-earth.net/5/45/2014/ Solid Earth, 5, 45-63, 2014 Table 2. Elastic constants in megabars (Mbar) calculated using Voigt-Reuss-Hill averaging and the elastic constants of enstatite (Chai et al, 1997a), diopside (Collins and Brown, 1998), garnet (Chai et al, 1997b), and olivine elastic tensors recalculated to account for the actual olivine Mg# in each sample, based on the single-crystal elastic constant tensors for fayalite, forsterite, and olivine with Mg# of 90, 91 and 93 (Kumazawa and Anderson, 1969;Suzuki et al, 1983;Webb et al, 1989;Isaak et al, 1993;Abramson et al, 1997). 3.…”

Section: Effect Of Compositional Variations On the Density And Isotromentioning

confidence: 99%

Petrophysical constraints on the seismic properties of the Kaapvaal craton mantle root

Baptiste

Tommasi

2014

Solid Earth

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Abstract.We calculated the seismic properties of 47 mantle xenoliths from 9 kimberlitic pipes in the Kaapvaal craton based on their modal composition, the crystal-preferred orientations (CPO) of olivine, ortho-and clinopyroxene, and garnet, the Fe content of olivine, and the pressures and temperatures at which the rocks were equilibrated. These data allow constraining the variation of seismic anisotropy and velocities within the cratonic mantle. The fastest P and S 2 wave propagation directions and the polarization of fast split shear waves (S 1 ) are always subparallel to olivine [100] axes of maximum concentration, which marks the lineation (fossil flow direction). Seismic anisotropy is higher for high olivine contents and stronger CPO. Maximum P wave azimuthal anisotropy (AV p ) ranges between 2.5 and 10.2 % and the maximum S wave polarization anisotropy (AV s ), between 2.7 and 8 %. Changes in olivine CPO symmetry result in minor variations in the seismic anisotropy patterns, mainly in the apparent isotropy directions for shear wave splitting. Seismic properties averaged over 20 km-thick depth sections are, therefore, very homogeneous. Based on these data, we predict the anisotropy that would be measured by SKS, Rayleigh (S V ) and Love (S H ) waves for five endmember orientations of the foliation and lineation. Comparison to seismic anisotropy data from the Kaapvaal shows that the coherent fast directions, but low delay times imaged by SKS studies, and the low azimuthal anisotropy with with the horizontally polarized S waves (S H ) faster than the vertically polarized S wave (S V ) measured using surface waves are best explained by homogeneously dipping (45 • ) foliations and lineations in the cratonic mantle lithosphere. Laterally or vertically varying foliation and lineation orientations with a dominantly NW-SE trend might also explain the low measured anisotropies, but this model should also result in backazimuthal variability of the SKS splitting data, not reported in the seismological data. The strong compositional heterogeneity of the Kaapvaal peridotite xenoliths results in up to 3 % variation in density and in up to 2.3 % variation of V p , V s , and V p /V s ratio. Fe depletion by melt extraction increases V p and V s , but decreases the V p /V s ratio and density. Orthopyroxene enrichment due to metasomatism decreases the density and V p , strongly reducing the V p /V s ratio. Garnet enrichment, which was also attributed to metasomatism, increases the density, and in a lesser extent V p and the V p /V s ratio. Comparison of density and seismic velocity profiles calculated using the xenoliths' compositions and equilibration conditions to seismological data in the Kaapvaal highlights that (i) the thickness of the craton is underestimated in some seismic studies and reaches at least 180 km, (ii) the deep sheared peridotites represent very local modifications caused and oversampled by kimberlites, and (iii) seismological models probably underestimate the compositional heterogeneity in the Kaapvaal man...

show abstract

The elasticity of the upper mantle orthosilicates olivine and garnet to 3 GPa

Cited by 126 publications

References 21 publications

The Seismic anisotropy of the Earth's mantle: From single crystal to polycrystal

The Seismic anisotropy of the Earth's mantle: From single crystal to polycrystal

Simultaneous determination of elastic and structural properties under simulated mantle conditions using multi-anvil device MAX80

Petrophysical constraints on the seismic properties of the Kaapvaal craton mantle root

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