Research

My research is currently focused on understanding the properties of hydrous phases stable at the extreme conditions of Earth's interior, as well as those of other bodies. I am predominantly an experimentalist but am also interested in the application of sophisticated statistical techniques and modeling to extract the most information possible from experimental data. The primary experimental techniques I use are synchrotron-based nuclear resonant spectroscopy and X-ray diffraction, performed at high pressure in the diamond anvil cell. Please read below for some examples of my past and present work!

High-Pressure Oxyhydroxides and water content of the lower mantle

CrystalStructure
The crystal structure of (Al,Fe)-phase H (Al0.84Fe3+0.07Mg0.02Si0.06OOH), with disordered hydrogen bonds at ambient conditions.

The recent discovery of hydrous phases which may be stable at the high pressures of Earth's lower mantle and along cold slab geotherms has cast doubt on the understanding of the lowermost mantle as a dry region of Earth's interior. Additionally. transport of these hydrous phases to the base of the lowermost mantle may explain the enigmatic anti-correlation of positive bulk sound velocities and negaticve shear-wave velocity anomalies at the edges of large, low shear-velocity provinces (LLSVPs). I am working to understand how such phases may alter seismic velocities of a hydrous, metabasalt in the lower mantle and whether high-pressure oxyhydroxides could reliably be discerned via seismic imaging.

Specifically, I am studying (Al,Fe)-phase H (left), an intermediate composition in the (δ-AlOOH)-(ε-FeOOH)-(MgSiO2(OH)2) system using various spectroscopic techniques employed at synchrotron facilities. Using X-ray diffraction and synchrotron Moessbauer spectroscopy, I have constrained the equation of state of this composition as well as the effect of a Fe3+ spin crossover on its compressibility (see publications below). Sound velocities of this composition will be constrained using nuclear resonant inelastic X-ray scattering (NRIXS). I also hope to better understand the crucial process of hydrogen bond symmetrization in this phase, with implications for the retention of hydrogen at high pressures and temperatures

Publications

Strozewski, B., et al. (2023) Equation of State and Spin Crossover of (Al,Fe)-phase H. Journal of Geophysical Research: Solid Earth, 128, doi:10/1029/2022JB026291

Micromechanical testing to constrain crustal rheology

Deformation of the lithosphere is a critical process in the evolution of Earth's surface and likely the development of plate tectonics, a convective process unique to Earth. Quartz is an abundant mineral in Earth's crust whose mechanical behavior plays a significant role in the deformation of the continental lithosphere. In this work, we constrained flow laws for quartz applicable to high-stress and moderate temperature conditions in Earth's crust, using nanoindentation. Nanoindentation is an experimental technique which uses a nanometer scale diamond tip to press into the sample with a defined peak load and load curve. The design of the tip suppresses fracture within the indent, allowing for constraints on the viscoplastic deformation of the sample, in this case quartz. Interestingly, examination of several samples of varying water (i.e. hydroxyl) content did not reveal a substantial weakening of quartz with increasing water content at this scale of deformation.

Publications

Strozewski, B., et al. (2021). Viscoplastic rheology of α-quartz investigated by nanoindentation. Journal of Geophysical Research: Solid Earth, 126, https://doi.org/10.1029/2021JB022229
CrystalStructure
Hardness values of synthetic and natural specimens of quartz, constrained using nanoindentation. This plot shows the apparent lack of influence that hydroxyl concentration had on nanoindentation strength in these experiments, as well as the decreasing hardness of quartz with increasing temperature (dashed lines).

Collaborations and Co-authored Publications

Pardo, O.S., Dobrosavljevic, V., Sturhahn, W., Toellner, T., Strozewski, B., and Jackson, J.M. (2023) Lattice dynamics, sound velocities, and atomic environments of szomolnokite at high pressure. Physics and Chemistry of Minerals. https://doi.org/10.1007/s00269-023-01255-4