Join us for our ESG Seminar Series speaker, Dr, Lowell Miyagi. Dr. Miyagi is a Professor in the Department of Geology and Geophysics at the University of Utah. Dr. Miyagi is a high pressure mineral physicist who studies how minerals deform at the pressure and temperature conditions of the core and deep mantle of Earth in order to understand the dynamic processes occurring with the Earth.

Dr. Lowell Miyagi
University of Utah
Department of Geology and Geophysics

Deformation of Minerals at Extreme Conditions: What can we learn about Earth’s interior?

The dynamic processes of Earth’s deep interior controls large scale surface processes (e.g. plate tectonics) and plays a vital role in our planet’s evolution as a habitable planet. Seismology provides the most direct observation of the Earth’s deep interior structure.  If these observations are combined with information on the physical properties of the appropriate mineral phases at high pressures and temperatures, seismic data can be used to infer the composition and dynamics of the Earth’s deep interior.

In the late 60’s it was realized that anisotropic propagation of seismic waves in the upper mantle is due to crystallographic preferred orientation (texture) of minerals that develops during mantle convection.  For upper mantle rocks the relationship between deformation geometry, texture development, and seismic anisotropy are well understood, and the use of anisotropy to study upper mantle flow has revolutionized our understanding of mantle processes.  However, our understanding of deeper regions of the Earth’s interior such as the lower mantle and inner core, are less well understood. Natural samples from these depths are not available and experimental deformation of these rocks and minerals is technically challenging.

High pressure and temperature deformation devices such as the diamond anvil cell and multi anvil press allow us to subject rocks and minerals to extreme conditions experienced in the Earth’s deep interior.  By combining ultra-high pressure and temperature deformation experiments with numerical models, we can study the deformation behavior of rocks and minerals in the Earth’s deep interior.  This talk will discuss mechanical properties and deformation mechanisms of rocks and minerals in the Earth’s interior, as well as the implications for understanding large scale flow, mantle convection and the evolution of the inner core.