# How much silicon is in the Earth's core, and how did it get there?

With some informal conversation with a peer of mine, he had suggested that there is evidence (which he couldn't find,but had remembered reading) that there was Silicon in the Earth's core. I referred to him to a rather famous paper by Micheal Drake which says:

"Further, there is no compelling experimental evidence that Si is extracted into the core under present core-mantle boundary conditions. For example, at the base of a high pressure/temperature terrestrial magma ocean, the metal/silicate partition coefficent for Si is approximately $10^{-3}$ to $10^{-2}$"

But since this paper was published 12 years ago, I am wondering if there is any compelling evidence that Si is in Earth's core, and at what concentration it might be? How might it have gotten there?

References

Drake, M., Righter, K., 2002. Determining the composition of the Earth. Nature 416, 39–44.

The only way presently is to simulate the conditions in the core, as has been performed in the article Oxygen and silicon contents of Earth's core from high pressure metal–silicate partitioning experiments (Ricolleau et al. 2011), whose results indicate that

that the oxygen metal–silicate partition coefficient increases with increasing oxygen fugacity, temperature and pressure, whereas the silicon metal-silicate partition coefficient increases with decreasing oxygen fugacity, increasing temperature and pressure.

The model also revealing that the approximate concentration of silicon in the core (outer core) is up to 11% wt%, depending on what model of core formation was used in the simulation. These results

in the core could satis!es the seismologically observed range of outer core density deficits.

In terms of how long the silicon is believed to have been in the core, in the article Silicon in the Earth’s core (Georg et al. 2007), similarities with the silicon content with the Moon led to their conclusion that

$Si$ was already incorporated as a light element in the Earth’s core before the Moon formed.