Susannah M Dorfman

Susannah M Dorfman
Michigan State University | MSU · Department of Earth and Environmental Sciences

Ph.D.

About

52
Publications
6,025
Reads
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486
Citations
Introduction
I perform experiments on physics and chemistry of materials at high pressures (up to 2.5 Mbar) and temperatures (up to 6000 K) to understand planetary interiors.
Additional affiliations
August 2015 - present
Michigan State University
Position
  • Professor (Assistant)
February 2012 - June 2012
École Polytechnique Fédérale de Lausanne
Position
  • Research Assistant
Description
  • MATH 206 “Analysis IV” for Physicists: Led problem solving sessions in complex analysis.
November 2011 - June 2015
École Polytechnique Fédérale de Lausanne
Position
  • Postdoctoral Scientist
Description
  • Initiated laser-heated diamond anvil cell research program at EPFL; used electron microscopy to characterize chemistry and texture of samples recovered from lower mantle pressures and temperatures.
Education
September 2006 - January 2012
Princeton University
Field of study
  • Geosciences
September 2001 - June 2005
Massachusetts Institute of Technology
Field of study
  • Earth, Atmospheric and Planetary Sciences

Publications

Publications (52)
Article
Full-text available
Recent experimental measurements of the equation of state of perovskites and post-perovskites in the (Mg,Fe)SiO3 and (Mg,Fe,Al)(Fe,Al,Si)O3 systems over a wide range of iron contents are used to constrain the effects of Fe and Al on density and bulk modulus of these phases at deep mantle pressures. The density of Fe-bearing perovskite follows a lin...
Article
Natural and synthetic pyrope–almandine compositions from 38 to 100 mol% almandine (Alm38–Alm100) were studied by synchrotron X-ray diffraction in the laser-heated diamond anvil cell to 177 GPa. Single-phase orthorhombic GdFeO3-type perovskites were synthesized across the entire examined compositional range at deep lower mantle pressures, with highe...
Article
Full-text available
We have performed a series of co-compression experiments on Au, Pt, Mo, MgO and NaCl to extend internally consistent pressure calibration and characterize shear strength of pressure media to 2.5 Mbar. Measured unit cell volumes of calibrants show differences between existing pressure scales of ˜10% above 2 Mbar. A new comprehensive pressure scale i...
Article
Fe-rich natural orthopyroxenes with compositions of (Mg0.61Fe0.38Ca0.01)SiO3 (Fe#38) and (Mg0.25Fe0.74Ca0.01)SiO3 (Fe#74) were studied at pressures up to 155GPa and temperatures up to 3000K. Single-phase orthorhombic GdFeO3-type perovskite was synthesized by heating to ~2000 K at 63GPa for the Fe#38 composition and at 72GPa for the Fe#74 compositio...
Article
Full-text available
Elastic and plastic properties of materials and phase transitions at extreme conditions vary with both hydrostatic pressure and deviatoric stress. To generate and measure controlled deviatoric stress at pressures beyond those accessible with large volume differential and rotational presses and optical access for spectroscopy, experiments tested the...
Article
Strength, texture, and equation of state of hexagonal tungsten monocarbide (WC) have been determined under quasi-hydrostatic and non-hydrostatic compression to 66 GPa using angle-dispersive X-ray diffraction in the diamond anvil cell. Quasi-hydrostatic compression in a Ne pressure medium demonstrates that nanocrystalline WC is slightly less incompr...
Article
Full-text available
Both seismic observations of dense low shear velocity regions and models of magma ocean crystallization and mantle dynamics support enrichment of iron in Earth’s lowermost mantle. Physical properties of iron-rich lower mantle heterogeneities in the modern Earth depend on distribution of iron between coexisting lower mantle phases (Mg,Fe)O magnesiow...
Article
Full-text available
Large Low Shear Velocity Provinces (LLSVPs) in the lowermost mantle are key to understanding the chemical composition and thermal structure of the deep Earth, but their origins have long been debated. Bridgmanite, the most abundant lower-mantle mineral, can incorporate extensive amounts of iron (Fe) with effects on various geophysical properties. H...
Article
Full-text available
The stable forms of carbon in Earth’s deep interior control storage and fluxes of carbon through the planet over geologic time, impacting the surface climate as well as carrying records of geologic processes in the form of diamond inclusions. However, current estimates of the distribution of carbon in Earth’s mantle are uncertain, due in part to li...
Article
We investigate seismic discontinuities in the mantle transition zone (MTZ) by analyzing SS precursors recorded at global seismic stations. Our observations confirm the global existence of the 520-km discontinuity. Although substantial regional depth variations in the 520-km discontinuity are generally correlated with temperature in the mid-MTZ, the...
Article
The isotopic compositions of iron in major mantle minerals may record chemical exchange between deep-Earth reservoirs as a result of early differentiation and ongoing plate tectonics processes. Bridgmanite (Bdg), the most abundant mineral in the Earth’s lower mantle, can incorporate not only Al but also Fe with different oxidation states and spin s...
Article
Full-text available
Iron nitrides are possible constituents of the cores of Earth and other terrestrial planets. Pressure‐induced magnetic changes in iron nitrides and effects on compressibility remain poorly understood. Here we report synchrotron X‐ray emission spectroscopy (XES) and X‐ray diffraction (XRD) results for ε‐Fe7N3 and γ′‐Fe4N up to 60 GPa at 300 K. The X...
Article
Full-text available
Calcium carbonate (CaCO3) is one of the most abundant carbonates on Earth's surface and transports carbon to Earth's interior via subduction. Although some petrological observations support the preservation of CaCO3 in cold slabs to lower mantle depths, the geophysical properties and stability of CaCO3 at these depths are not known, due in part to...
Article
Full-text available
Electronic states of iron in the lower mantle's dominant mineral, (Mg,Fe,Al)(Fe,Al,Si)O3 bridgmanite, control physical properties of the mantle including density, elasticity, and electrical and thermal conductivity. However, the determination of electronic states of iron has been controversial, in part due to different interpretations of Mössbauer...
Preprint
33 Reactions involving carbon in the deep Earth have limited manifestation on Earth's surface, yet 34 they have played a critical role in the evolution of our planet. The metal-silicate partitioning 35 reaction promoted carbon capture during Earth's accretion and may have sequestered substantial 36 carbon in Earth's core. The freezing reaction invo...
Article
Full-text available
Reactions involving carbon in the deep Earth have limited manifestations on Earth’s surface, yet they have played a critical role in the evolution of our planet. The metal-silicate partitioning reaction promoted carbon capture during Earth’s accretion and may have sequestered substantial carbon in Earth’s core. The freezing reaction involving iron-...
Article
Full-text available
Here, the room temperature piezospectroscopic response of highly-fluorescent, ∼330 nm-thick pulsed laser deposited crystalline ruby (0.05 wt. % Cr³⁺ doped α-Al2O3) thin films on either (001)-oriented sapphire or (001)-oriented yttria-stabilized zirconia wafers was investigated and calibrated against biaxial film stress measurements obtained from a...
Article
Carbonate minerals are important hosts of carbon in the crust and mantle with a key role in the transport and storage of carbon in Earth's deep interior over the history of the planet. Whether subducted carbonates efficiently melt and break down due to interactions with reduced phases or are preserved to great depths and ultimately reach the core-m...
Article
Full-text available
Heterogeneity in Earth's mantle is a record of chemical and dynamic processes over Earth's history. The geophysical signatures of heterogeneity can only be interpreted with quantitative constraints on effects of major elements such as iron on physical properties including density, compressibility, and electrical conductivity. However, deconvolution...
Chapter
Diamond anvil cell (DAC) is a unique tool to study materials under static high pressures up to several hundreds of GPa comparable to the pressures in the earth and planets interior. By using laser heating the temperature of the material inside the cell can be raised to several thousand degrees. This allows us to reach to the pressure and temperatur...
Article
Valence and spin states of Fe were investigated in a glass of almandine (Fe3Al2Si3O12) composition to 91 GPa by X-ray emission spectroscopy and energy- and time-domain synchrotron Mössbauer spectroscopy in the diamond-anvil cell. Changes in optical properties, total spin moment and Mössbauer parameters all occur predominantly between 1 bar and ~30...
Article
Full-text available
Seismic tomography models reveal two large low shear velocity provinces (LLSVPs) that identify large-scale variations in temperature and composition in the deep mantle. Other characteristics include elevated density, elevated bulk sound speed, and sharp boundaries. We show that properties of LLSVPs can be explained by the presence of small quantiti...
Chapter
This chapter summarizes experimental and computational approaches to phase equilibria of the lower mantle and their uncertainties. It describes the thermodynamic properties of mantle materials in the context of modeling equilibria. Recent experimental data and the thermodynamic code developed by Stixrude and Lithgow-Bertelloni are applied to the ph...
Article
Spin transitions in (Mg,Fe)SiO3 bridgmanite have important implications for the chemistry and dynamics of Earth’s lower mantle, but have been complex to characterize in experiments. We examine the spin state of Fe in highly Fe-enriched bridgmanite synthesized from enstatites with measured compositions (Mg0.61Fe0.38Ca0.01)SiO3 and (Mg0.25Fe0.74Ca0.0...
Article
Full-text available
Angle-and energy-dispersive X-ray diffraction experiments in a radial geometry were performed in the diamond anvil cell on polycrystalline platinum samples at pressures up to 63 GPa. Observed yield strength and texture depend on grain size. For samples with 70-300-nm particle size, the yield strength is 5-6 GPa at ~60 GPa. Coarse-grained (~2-µm par...
Article
Polycrystalline ruby (α-Al2O3:Cr3+), a widely used pressure calibrant in high-pressure experiments, was compressed to 68.1 GPa at room temperature under non-hydrostatic conditions in a diamond anvil cell. Angle-dispersive X-ray diffraction experiments in a radial geometry were conducted at beamline X17C of the National Synchrotron Light Source. The...
Article
The equation of state and compression behavior of lithium fluoride, LiF, have been determined to 92 GPa by X-ray diffraction in a diamond anvil cell. A neon pressure-transmitting medium was used to minimize the effect of differential stress on the sample. Consistent results using multiple pressure standards were obtained. By fitting the pressure–vo...
Article
The compression behavior and stress state of nanocrystalline tungsten boride (WB) were investigated using radial x-ray diffraction (RXRD) in a diamond-anvil cell under non-hydrostatic compression up to 60.4 GPa. The compression properties and stress state are analyzed using lattice strain theory. Experiments were conducted at beamline X17C of the N...
Article
The formation and properties of the post-perovskite (CaIrO3-type) phase were studied in Fe-rich compositions along the pyrope–almandine ((Mg,Fe)3Al2Si3O12) join. Natural and synthetic garnet starting materials with almandine fractions from 38 to 90 mol% were studied using synchrotron X-ray diffraction in the laser-heated diamond anvil cell. Single-...
Article
Seismic tomography has characterized dense large low shear velocity provinces (LLVSPs) and ultra-low velocity zones (ULVZs) at the base of the Earth's lower mantle. The morphology and seismic properties of these regions indicate that chemical heterogeneity plays a major role in these features. It is therefore important to characterize how Fe enrich...
Article
Accurate pressure measurements are essential for experimental measurements of phase transitions and physical properties of materials under conditions of the Earth's deep interior. Pressure scales based upon shock compression experiments suffer from uncertainties at high compressions due to corrections for thermal effects. Independent pressure scale...
Article
Full-text available
Gd3Ga5O12 (GGG), which crystallizes in the garnet structure at ambient conditions, was observed to transform to a high-pressure phase at 88 GPa after laser heating at 1500 K. This new phase is stable at least up to 180 GPa, and can be preserved on decompression to 50 GPa. This phase is cubic and consistent with a perovskite structure of stoichiomet...
Article
Orthopyroxene ((Mg,Fe)SiO3) is one of the dominant phases in Earth's upper mantle - it makes up ~20% of the upper mantle by volume. At high pressures and temperatures, this phase undergoes several well-characterized phase transitions. However, when compressed at low temperature and high-pressure, orthopyroxene is predicted to exhibit metastable beh...
Article
Phase transitions and equations of state of the alkaline earth fluorides CaF2, SrF2, and BaF2 were examined by static compression to pressures as high as 146 GPa. Angle-dispersive x-ray diffraction experiments were performed on polycrystalline samples in the laser-heated diamond-anvil cell. We confirmed that at pressures less than 10 GPa all three...
Article
The garnet structure type is of fundamental importance in Earth [1] and materials science. High-pressure investigations of oxide garnets composed of transition and rare earth elements have revealed a range of interesting phenomena including pressure-induced amorphization, phase transitions, magnetic collapse, and potential transformation to superha...
Article
Fe and Al are important elements in Earth's mantle and they may be concentrated in lower mantle chemical heterogeneities associated with subducting slabs, mantle plumes, or core-mantle reaction products. We studied an almandine garnet composition to explore the stability and physical properties of phases in this system at high P-T. Previous multi-a...
Article
Fe and Al are two of the most abundant minor elements in the lower mantle and may have significant effects on the stability and elastic properties of the region's dominant phase, MgSiO3 perovskite. In order to predict the chemical and physical behavior of lower mantle chemical heterogeneities enriched in Fe and Al, we investigated perovskites synth...
Article
AX2 compounds include a wide range of oxides and salts of broad interest in geoscience, materials science and chemistry, such as SiO2 and CaF2, and have in common a sequence of phase transitions dependent on ionic size ratio and electronic properties (Leger and Haines, 1997). Shock compression studies have shown that CaF2 transforms to a highly inc...
Thesis
We explored two complementary mechanisms for change in porosity and permeability of geomaterials: thermal cracking and crack healing by diagenesis. A suite of thermal cracking experiments was performed on andesite plugs from the geothermal field in Awibengkok, Indonesia. Permeability (k) and specific storage capacity were measured by the oscillatin...

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