Shock and shock-ramp compression of iron-rich (Mg,Fe)O at Earth's core conditions

Where Earth’s iron core and silicate mantle meet is a region of the Earth’s interior that is still poorly understood. Seismological results suggest the presence of ultra-low velocity zones (ULVZ’s) sitting directly atop the core. One possible explanation for these features is that they are regions of highly iron-enriched ferropericlase (Mg,Fe)O (Wicks et al. 2010), however the thermodynamic properties at near-core conditions are poorly constrained. Here we present the results of combined ab-initio calculations and shock measurements of (Mg,Fe)O containing 25 and 50 mol% Fe. The results are being used to design shock-ramp experiments on the Z machine at Sandia National Laboratories.

Wicks, J. K., Jackson, J. M., & Sturhahn, W. (2010) Very low sound velocities in iron‐rich (Mg, Fe) O: Implications for the core‐mantle boundary region. Geophysical Research Letters, 37(15).