CSEDI: Experimental Constraints on Dynamic Processes in Earth's Core

Case Western Reserve University, Cleveland OH

Investigators

Abstract

The transport properties of iron alloys are central to the understanding of dynamic processes in the Earth's core, including convective motions in the outer core (which drive the geodynamo) and solid-state deformation in the inner core, which may be responsible for the observed seismic anisotropy. To better understand these processes the PIs propose to conduct experimental studies of diffusional transport in iron at high pressure (up to 27 GPa). Rates of diffusion of several chemical species (Fe, S, O, and Os) will be measured in both liquid iron and in high-pressure solid phases (fcc and hcp). The experiments will extend to significantly higher pressures than have been examined previously and will provide a more secure basis for extrapolating diffusion rates and diffusion-related properties to the conditions of the core. The results will lead to a better understanding of inner core rheology and mechanisms for producing anisotropic textures; the viscosity and role of compositional convection in the outer core; and the spatial distribution of osmium isotopes and other chemical species within the core.