Inner core composition paradox revealed by sound velocities of Fe and Fe-Si alloy.

ABSTRACT: Knowledge of the sound velocity of core materials is essential to explain the observed anomalously low shear wave velocity (V_S) and high Poisson's ratio (σ) in the solid inner core. To date, neither V_S nor σ of Fe and Fe-Si alloy have been measured under core conditions. Here, we present V_S and σ derived from direct measurements of the compressional wave velocity, bulk sound velocity, and density of Fe and Fe-8.6 wt%Si up to ~230 GPa and ~5400 K. The new data show that neither the effect of temperature nor incorporation of Si would be sufficient to explain the observed low V_S and high σ of the inner core. A possible solution would add carbon (C) into the solid inner core that could further decrease V_S and increase σ. However, the physi

SUBMITTER: Huang H 

PROVIDER: S-EPMC8807611 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature