Preprints

Filtering by Subject: Mineral Physics

High-angular resolution electron backscatter diffraction as a new tool for mapping lattice distortion in geological minerals

David Wallis, Lars Hansen, T. Ben Britton, et al.

Published: 2019-04-18
Subjects: Earth Sciences, Geology, Mineral Physics, Physical Sciences and Mathematics

Analysis of distortions of the crystal lattice within individual mineral grains is central to the investigation of microscale processes that control and record tectonic events. These distortions are generally combinations of lattice rotations and elastic strains, but a lack of suitable observational techniques has prevented these components being mapped simultaneously and routinely in earth [...]

Core Formation and Geophysical Properties of Mars

Matthew C Brennan, Rebecca A Fischer, Jessica C. E. Irving

Published: 2019-02-25
Subjects: Earth Sciences, Geochemistry, Mineral Physics, Physical Sciences and Mathematics, Planetary Geophysics and Seismology, Planetary Sciences

The chemical and physical properties of the interiors of terrestrial planets are largely determined during their formation and differentiation. Modeling a planet’s formation provides important insights into the properties of its core and mantle, and conversely, knowledge of those properties may constrain formational narratives. Here, we present a multi-stage model of Martian core formation in [...]

Structure and elasticity of phlogopite under compression: Geophysical implications

Tanvi Chheda

Published: 2018-10-10
Subjects: Earth Sciences, Mineral Physics, Physical Sciences and Mathematics

We investigated the response of the crystal structure, lattice parameters, and unit-cell volume of hydrous layered silicate phlogopite at conditions relevant to subduction zone settings. We have used first principles simulation based on density functional theory to calculate the equation of state and full elastic constant tensor. Based on the generalized gradient approximation, the full single [...]

Segregation of bare and protonated Mg vacancies to dislocation cores in MgO

Richard Skelton, Andrew Walker

Published: 2018-09-27
Subjects: Earth Sciences, Mineral Physics, Physical Sciences and Mathematics

Water can be incorporated into the lattice of mantle minerals in the form of protons charge-balanced by the creation of cation vacancies. These protonated vacancies, when they interact with dislocations, increase strain rates by enhancing dislocation climb and, potentially, by reducing the Peierls barrier to glide. We use atomic scale simulations to investigate segregation of Mg vacancies to [...]

Atomistic simulations of Mg vacancy segregation to dislocation cores in forsterite

Richard Skelton, Andrew Walker

Published: 2018-09-27
Subjects: Earth Sciences, Mineral Physics, Physical Sciences and Mathematics

Interactions between dislocations in olivine and extrinsic cation vacancies created under hydrous or oxidizing conditions may influence the rheology of the Earths upper mantle. In this study, we use atomic-scale simulations to calculate segregation energies for bare and protonated Mg vacancies to M1 and M2 sites in the core regions of [100](010) and [001](010) edge dislocations, and [100] and [...]

Lubrication of dislocation glide in forsterite by Mg vacancies: insights from Peierls-Nabarro modeling

Richard Skelton, Andrew Walker

Published: 2018-07-26
Subjects: Condensed Matter Physics, Earth Sciences, Geophysics and Seismology, Mineral Physics, Physical Sciences and Mathematics, Physics

Dislocation glide is an important contributor to the rheology of olivine under conditions of high stress and low to moderate temperature, such as occur in mantle wedges. Interactions between point defects and dislocation core may alter the Peierls stress,

Tracking CO2 plumes in clay-rich rock by distributed fiber optic strain sensing (DFOSS): a laboratory demonstration

Yi Zhang, Ziqiu Xue, Hyuck Park, et al.

Published: 2018-04-26
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Fluid Dynamics, Geology, Geophysics and Seismology, Hydrology, Mineral Physics, Oil, Gas, and Energy, Optics, Physical Sciences and Mathematics, Physics

Monitoring the migration of pore pressure, deformation, and saturation plumes with effective tools is important for the storage and utilization of fluids in underground reservoirs, such as geological stores of carbon dioxide (CO2) and natural gas. Such tools would also verify the security of the fluid contained reservoir–caprock system. Utilizing the swelling strain attributed to pressure [...]

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