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Exploration of Earth's Deep Interior by Merging Nanotechnology, Diamond-Anvil Cell Experiments, and Computational Crystal Chemistry

Pigott, Jeffrey Scott
http://rave.ohiolink.edu/etdc/view?acc_num=osu1435154850

Abstract Details

2015, Doctor of Philosophy, Ohio State University, Geological Sciences.
The structure, dynamics, and composition of Earth’s deep interior have direct control on plate tectonics and surface-to-interior exchange of material, including water and carbon. To properly interpret geophysical data of the Earth’s interior, accurate and precise measurements of the material properties of the constituent mineral phases are required. Additionally, experimentally derived data need to be augmented by computational chemistry and modeling of physical properties to elucidate the effect of compositional variations and deep storage of volatile components (e.g. H2O and CO2) within the crystalline phases. This dissertation uses in situ high pressure, high-temperature experiments in the laser-heated diamond anvil cell (LHDAC) coupled with synchrotron-based x-ray diffraction. The thermal expansion and bulk modulus of Ni and SiO2 are measured to P = ~110 GPa and T = ~3000 K. Nickel is a significant component of the Earth’s core and SiO2 is the fundamental building block of the Earth’s mantle and crust. We have designed the first controlled-geometry samples of Ni and SiO2, manufactured using nanofabrication techniques, and specifically tuned to reduce systematic errors in the measurement. Knowledge of the thermoelastic properties of Ni and SiO2 has implications for subduction rates, plume buoyancy, dynamics of the Earth’s convective heat engine, and planetary formation. Complimentary to the Ni/SiO2 experiments, the energetics of different hydrogen defect mechanisms in garnet (MgSiO3-Mg3Al2Si3O12) and associated geophysical properties (P- and S-wave velocities) are calculated using atomistic simulations and first-principles calculations to a depth of 700 km. Garnet accounts for as much as 40 percent of the rock volume at 500 km. By calculating and comparing the defect energies associated with charge-balanced substitutions of hydrogen for magnesium or silicon, the hydrogarnet defect has the lowest energy and is therefore predicted to be the most favorable in the garnet structure. The fundamental question of the planet’s water budget has implications for the formation history of the planet and the cycling of volatile compounds between the surface and the interior.
Wendy Panero (Advisor)
Berry Lyons (Committee Member)
Michael Barton (Committee Member)
David Cole (Committee Member)
130 p.
Earth; Geological
X-ray Diffraction, Focused Ion Beam, Nanofabrication, Diamond-Anvil Cell, High Pressure, Equation of State, Nickel, Stishovite, Hydrous Majorite, Defect Mechanisms, Force Field, Computer Simulation, Density Functional Theory

Recommended Citations

Citations

  • Pigott, J. S. (2015). Exploration of Earth's Deep Interior by Merging Nanotechnology, Diamond-Anvil Cell Experiments, and Computational Crystal Chemistry [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1435154850

    APA Style (7th edition)

  • Pigott, Jeffrey. Exploration of Earth's Deep Interior by Merging Nanotechnology, Diamond-Anvil Cell Experiments, and Computational Crystal Chemistry. 2015. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1435154850.

    MLA Style (8th edition)

  • Pigott, Jeffrey. "Exploration of Earth's Deep Interior by Merging Nanotechnology, Diamond-Anvil Cell Experiments, and Computational Crystal Chemistry." Doctoral dissertation, Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1435154850

    Chicago Manual of Style (17th edition)

osu1435154850
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© 2015, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.