6 papers
Characterizing Dislocation Substructures in Creep-Deformed Olivine Using Electron Channeling Contrast Imaging
M. Haroon Qaiser, Jessica White, David Wallis +1
Olivine is the dominant mineral in Earth's upper mantle and therefore controls mantle rheology and the mechanics of plate tectonics. The constitutive laws for dislocation-mediated…
The Effect of Pattern Quality on Measurements of Stress Heterogeneity and Geometrically Necessary Dislocation Density by High-Angular Resolution Electron Backscatter Diffraction
Harison S. Wiesman, David Wallis
We examine the effect of pattern quality on the output of high-angular resolution electron backscatter diffraction (HR-EBSD) analyses. Band contrast, as a proxy for pattern quality…
Microstructural evolution of Carrara marble during semi-brittle deformation
Tongzhang Qu, Nicolas Brantut, David Wallis +1
Fifteen marble samples were subjected to semi-brittle deformation through triaxial compression experiments, reaching axial strains of 0.5%, 1.0%, 2.0%, 4.0%, or 7.5% at temperature…
Microstructural and Micromechanical Evolution of Olivine Aggregates During Transient Creep
Harison S. Wiesman, Thomas Breithaupt, David Wallis +1
To examine the microstructural evolution that occurs during transient creep, we deformed olivine aggregates to different strains that spanned the initial transient deformation. Two…
Mild-to-wild plasticity of Earth's upper mantle
David Wallis, Kathryn M. Kumamoto, Thomas Breithaupt
The flow of Earth's upper mantle has long been considered to occur by slow and near-continuous creep. Such behaviour is observed in classical high-temperature deformation experimen…
Transient and steady-state dislocation creep of olivine controlled by dislocation interactions at the isostress endmember
David Wallis, Thomas Breithaupt, Taco Broerse
The rheological behaviour of olivine deforming by dislocation creep controls geodynamic processes that involve steady-state flow or transient viscosity evolution. Longstanding rheo…