The Earth’s inner core is the youngest major feature of the Earth, slowly growing from the inside out at temperatures and pressures of ~6000K and 3.6 Mbar. The dynamics of this region are a consequence of its composition, mineralogy, and viscosity, while influencing the Earth’s magnetic field and moment of inertia. Recent seismic results show significant heterogeneous features, suggesting that it is undergoing a dynamic process of unknown origin.
This talk presents new methods for measuring transport properties under the high-pressure, high-temperature conditions of the Earth’s core, combining synchrotron-based X-ray experiments at high pressure and temperature with post-run focused-ion beam milling and transmission electron microscopy. Together with models for texture evolution in metals, the mechanism by which the inner core develops and maintains anisotropy appears to be a combination of preferential growth in equatorial regions combined with solid-state deformation in response to mass variations in the Earth’s mantle.