Fifty years ago, the wide-spread acceptance of plate tectonic theory spawned generations of scientists eager to understand plate motions and their influence over the geologic processes that affect life at Earth’s surface. Earth’s tectonic plates are characterized by interiors that may be stable over billions of years. However, the actively deforming boundaries between plates are subject to modification over much shorter time scales through the growth of mountains, the creation or recycling of lithosphere, and the transformation of landscapes by volcanic, seismogenic, and hydrologic processes. Earth’s particular style of plate tectonics appears to be unique in the solar system and undoubtedly contributes to some of the basic differences between the evolution of Earth and the other terrestrial planets. However, many fundamental questions about plate tectonics persist. What are the patterns of underlying mantle flow and what can we learn from these flow patterns about the convective forces that drive plate tectonics? What are the rheological properties of the rocks that make up the crust and mantle? How do plates form narrow, dynamic boundaries? How does plate tectonics begin in the first place?
I use geologic observations and experimental methods to study how rocks deform. My strategy is to use the micro- to meso-scale structures (~10-9-101m) of naturally deformed, highly sheared rocks from plate boundaries to assess the relative importance of specific deformation processes in Earth. I design rock deformation experiments to test the sensitivity of these processes to temperature, pressure, grain-size, chemical composition, and the magnitude of strain. Experimental data are then used to model how materials deform in parts of the Earth or other planetary interiors that are inaccessible to direct observation. I am particularly interested in the complex feedbacks between rheology and microstructure in the materials that make up the crust and mantle. Through my research, I seek to provide physically meaningful connections between geodynamic theory and models, seismological data, and direct geological observations.
Looking for PhD programs?
If you are interested in structural geology, rock mechanics, or geodynamics, and enjoy working with your hands, please send me an email. I would be happy to discuss my research program and graduate education at Washington University.
- Cross A.J., Skemer P. (2019) Rates of dynamic recrystallization in geologic materials. Journal of Geophysical Research: Solid Earth, 10.1029/2018JB016201
- Boneh Y., Wallis D., Hansen L.N., Krawczynski M., Skemer P. (2017) Oriented grain growth and modification of ‘frozen anisotropy’ in the lithospheric mantle. Earth and Planetary Science Letters, 474:368-374, https://doi.org/10.1016/j.epsl.2017.06.050
- Bercovici D., Skemer, P. (2017) Grain damage, phase miing and plate-boundary formation. Journal of Geodynamics, 108:40-55, http://dx.doi.org/10.1016/j.jog.2017.05.002
- Skemer P., Chaney M.M., Emmerich A.L., Miller K.J., Zhu W. (2017) Network topology of olivine – basalt partial melts. Geophysical Journal International, 210:284-290, doi:10.1093/gji/ggx160
- Cross A.J., Skemer P. (2017) Ultramylonite generation via phase mixing in high strain experiments. Journal of Geophysical Research: Solid Earth, doi: 10.1002/2016JB013801
- Hansen L.N., Conrad C.P., Boneh Y., Skemer P., Warren J.M., Kohlstedt D.L. (2016) Viscous anisotropy of textured olivine aggregates: 2. Micromechanical model . Journal of Geophysical Research: Solid Earth, doi: 10.1002/2016JB013240
- Rahl J.M., Skemer P. (2016) Microstructural evolution and rheology of quartz in a mid-crustal shear zone. Tectonophysics, http://dx.doi.org/10.1016/j.tecto.2016.05.022
- Kranjc K., Rouse Z., Flores K., Skemer P. (2016) Low temperature plastic rheology of olivine determined by nanoindentation. Geophysical Research Letters, 43, doi: 10.1002/2015GL065837
- Skemer P., Hansen L.N. (2016) Inferring upper-mantle flow from seismic anisotropy: An experimental perspective. Tectonophysics, http://dx.doi.org/10.1016/j.tecto.2015.12.003
- Boneh Y., Morales L.F.G, Kaminski E., Skemer P. (2015) Modeling olivine CPO evolution with complex deformation histories—Implications for the interpretation of seismic anisotropy in the mantle. G3, doi:10.1002/2015GC005964
EPS 104: Freshman Seminar: Geology in the Field
EPS 201: Earth and the Environment
EPS 361/460: Structural Geology
EPS 496: Undergraduate Field Geology
EPS 580: Deformation of Planetary Materials