An Experimental Investigation of the Relative Strength of the Silica Polymorphs Quartz, Coesite, and Stishovite

Hunt, Simon A.; Whitaker, M. L.; Bailey, E. Fiona; Mariani, Elisabetta; Stan, Camelia; Dobson, David P.

doi:10.1029/2018gc007842

Cited by 13 publications

(8 citation statements)

References 89 publications

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“…Two‐layered samples of post‐spinel and bridgmanite aggregate were stacked along the compression column together for deformation. As the same stress and chemical condition of deformation (e.g., oxygen fugacity, water fugacity), we can have a direct comparison of the relative strengths of the sample by the strain contrast (e.g., Hunt et al., 2019; Li et al., 2007). To avoid the deformation of sample during cold compression, crushable Al 2 O 3 pistons were set at the two ends of the sample column.…”

Section: Methodsmentioning

confidence: 99%

Deformation of Post‐Spinel Under the Lower Mantle Conditions

Hunt

Tsujino

et al. 2022

JGR Solid Earth

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To study the viscosity of bridgmanite and ferropericlase aggregate, uniaxial compression deformation experiments on pre‐synthesized post‐spinel phase and bridgmanite two‐layered samples were conducted under top lower mantle pressure and 1773 K utilizing DT‐Cup apparatus. Up to the strain of 0.25 ± 0.05, the observed comparable strain of the bridgmanite and post‐spinel samples suggests the bridgmanite dominates the bulk viscosity of the post‐spinel without strain localization in periclase. The microstructures of the deformed post‐spinel samples show evidence of a similar strain of periclase with the bulk strain without strain partitioning. Texture analyses of bridgmanite indicate a dominant slip plane (100), with a steady state fabric strength achieved within the strain of 0.12 ± 0.01. The current experiment has provided no evidence about an onset of strain localization of ∼30 vol.% periclase at 0.25 strain. Our observations provide direct experimental verification of bridgmanite controlled rheology under low strain magnitude, which should be considered in geodynamical models which include mantle compositional and rheological evolution in the lower mantle.

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Section: Methodsmentioning

confidence: 99%

Deformation of Post‐Spinel Under the Lower Mantle Conditions

Hunt

Tsujino

et al. 2022

JGR Solid Earth

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“…The GGBFS also shows the presence of crystals of coesite (100%), a polymorph of crystalline silicon dioxide. 36 The PKS contains kaolinite (77%) and quartz (22.6%). A Nicolet FTIR device was used to collect spectra data within the 400–4000 cm –1 range.…”

Section: Methodsmentioning

confidence: 99%

“…The diffractogram (Figure ) shows that the GGBFS is highly amorphous, showing a hump at 25–35°, 2θ°. The GGBFS also shows the presence of crystals of coesite (100%), a polymorph of crystalline silicon dioxide . The PKS contains kaolinite (77%) and quartz (22.6%).…”

Section: Methodsmentioning

confidence: 99%

Effect of Elevated Temperature on the Microstructure of Metakaolin-Based Geopolymer

2022

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Currently, geopolymer is being considered as a future oil-well cement. For wellbore applications, geopolymers are initially tested at specific temperature conditions. However, an oil-wellbore may experience a sudden increase in temperature which may adversely affect geopolymer systems designed for low to moderate temperature conditions. In this work, the effect of elevated temperatures on the microstructure of the geopolymer was simulated. Metakaolin-based geopolymer systems cured at 163 °F for 48 h were subjected to a temperature ramp of 194 °F and 248 °F for 24 h. X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetry analysis techniques were used to study the microstructural changes. The analytical techniques show the formation of new crystalline phases when the geopolymer cured at 163 °F was suddenly exposed to higher temperatures. These crystalline phases, for instance, gobbinsite and anorthite, observed in the microstructure have the potential to cause thermal stress, weaken the system, and ultimately affect the geopolymer’s ability to effectively isolate the formation and support the casing.

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“…In addition to bridgmanite, ferropericlase and ringwoodite, stishovite is also present in our sample. While only a small fraction of the aggregate by volume (Table 1), stishovite is comparatively stiff (Hunt et al, 2019) to ringwoodite (Miyagi et al, 2009) and could thus also behave similarly to Ca-silicate perovskite.…”

Section: Presence Of Ringwooditementioning

confidence: 99%

Does Heterogeneous Strain Act as a Control on Seismic Anisotropy in Earth’s Lower Mantle?

et al. 2020

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Plastic deformation and texture development in minerals of the lower mantle can result in seismic anisotropy, and studying deformation of lower mantle materials is therefore important for interpreting lower mantle flow. Most previous deformation experiments documenting texture development at lower mantle pressures have been conducted on single-phase samples and/or at room temperature. However, real rocks deform at high temperature and are poly-phase and deformation is therefore likely different from that of a single phase. Here we report on high temperature diamond anvil cell deformation experiments on a multiphase assemblage of bridgmanite, ferropericlase, and ringwoodite compressed from ∼28 to ∼39 GPa and resistively heated at a constant temperature of 1,000 K. We employ the elasto-viscoplastic self-consistent method to model both texture and lattice strain of bridgmanite as a function of deformation mechanisms. Simulations indicate deformation of bridgmanite is accommodated by about half of slip activity on (100)[010] with the remainder split between (100)[001] and/or (100)〈011〉. Texture in bridgmanite is consistent with most seismic observations in the lowermost mantle. Although there is texture development in both bridgmanite and ringwoodite, ferropericlase does not develop coherent texture throughout the course of the experiment. Analysis of lattice strains suggests that the lack of coherent texture development in ferropericlase is due to heterogeneous plastic deformation resulting from microstructural interactions imposed by other phases. Variations in texturing of bridgmanite and ferropericlase could therefore cause laterally varying, complex anisotropy. Our models for binary mantle-like mixtures of bridgmanite and ferropericlase show that changes in strain and texture partitioning can explain the range of observed lower mantle anisotropies.

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An Experimental Investigation of the Relative Strength of the Silica Polymorphs Quartz, Coesite, and Stishovite

Cited by 13 publications

References 89 publications

Deformation of Post‐Spinel Under the Lower Mantle Conditions

Deformation of Post‐Spinel Under the Lower Mantle Conditions

Effect of Elevated Temperature on the Microstructure of Metakaolin-Based Geopolymer

Does Heterogeneous Strain Act as a Control on Seismic Anisotropy in Earth’s Lower Mantle?

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