<p>The radius of the Earth is 6371 km. The <a href="https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole" rel="nofollow noreferrer">deepest hole drilled</a> reached a depth of 12.262 km, which is a long way from the center of the Earth. We haven't even punched the crust and reached the upper mantle. Consequently, we haven't been able to directly sample the Earth's core to accurately determine its composition.</p>
<p>Its <a href="https://en.wikipedia.org/wiki/Earth%27s_inner_core#Composition" rel="nofollow noreferrer">composition</a> is based on inference,</p>
<blockquote>
<p>There is still no direct evidence about the composition of the inner core. However, based on the relative prevalence of various chemical elements in the Solar System, the theory of planetary formation, and constraints imposed or implied by the chemistry of the rest of the Earth's volume, the inner core is believed to consist primarily of an iron–nickel alloy.</p>
<p>At the known pressures and estimated temperatures of the core, it is predicted that pure iron could be solid, but its density would exceed the known density of the core by approximately 3%. That result implies the presence of lighter elements in the core, such as silicon, oxygen, or sulfur, in addition to the probable presence of nickel. Recent estimates (2007) allow for up to 10% nickel and 2–3% of unidentified lighter elements.</p>
<p>... the liquid outer core contains 8–13% of oxygen, but as the iron crystallizes out to form the inner core the oxygen is mostly left in the liquid.</p>
</blockquote>
<p>Subsequently, there is no list of the abundances of all the elements that exist in the Earth's core. Some of the lighter elements do not occur within the core.</p>

CC BY-SA 4.0
2023-11-19T00:29:51.907Z
2023-11-19T07:41:32.193Z
2023-11-19T07:41:32.193Z
Fred
<p>Is there a list giving an estimate of the abundance of every element of the periodic table in the Earth's Core - possibly differentiating by inner core and outer core?</p>
<p>I am specifically interested in estimates for extremely rare trace elements.</p>

CC BY-SA 4.0
2023-11-17T15:31:50.280Z
@Agerhell: What are the rules for crossposting? Is it possible to move a question?
catalyst
<geophysics>
Composition of Earth's Core
catalyst
# Composition of Earth's Core

(Asked by: username_0 on 2023-11-17)

Is there a list giving an estimate of the abundance of every element of the periodic table in the Earth's Core - possibly differentiating by inner core and outer core?

I am specifically interested in estimates for extremely rare trace elements.

**Tags:** geophysics

> **Comments:**
> **username_0**: @Agerhell: What are the rules for crossposting? Is it possible to move a question?  

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## 1 answers

### Answer by username_1 on 2023-11-19. Score: 3

The radius of the Earth is 6371 km. The [deepest hole drilled](https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole) reached a depth of 12.262 km, which is a long way from the center of the Earth. We haven't even punched the crust and reached the upper mantle. Consequently, we haven't been able to directly sample the Earth's core to accurately determine its composition.

Its [composition](https://en.wikipedia.org/wiki/Earth%27s_inner_core#Composition) is based on inference,

> There is still no direct evidence about the composition of the inner core. However, based on the relative prevalence of various chemical elements in the Solar System, the theory of planetary formation, and constraints imposed or implied by the chemistry of the rest of the Earth's volume, the inner core is believed to consist primarily of an iron–nickel alloy.
>
> At the known pressures and estimated temperatures of the core, it is predicted that pure iron could be solid, but its density would exceed the known density of the core by approximately 3%. That result implies the presence of lighter elements in the core, such as silicon, oxygen, or sulfur, in addition to the probable presence of nickel. Recent estimates (2007) allow for up to 10% nickel and 2–3% of unidentified lighter elements.
>
> ... the liquid outer core contains 8–13% of oxygen, but as the iron crystallizes out to form the inner core the oxygen is mostly left in the liquid.

Subsequently, there is no list of the abundances of all the elements that exist in the Earth's core. Some of the lighter elements do not occur within the core.


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