Last Layers of Terrestrial Magma Ocean Solidification

• Magma ocean solidifies from the bottom up

• Last 0.3% of mantle not solidified by model

• Leftover “exotic” mix of oxides in melt

– CaO (50%), FeO (27%), Al2O3 (20%), SiO2

(3%), MgO (1%)

– Enriched in Nd, Sm, U, Th too!

• What happens to the leftover material?A. Springmann, 12.470, May 14 2009

Exotic Oxide Solidification

• Create a melt with appropriate composition

• Use multi-anvil press (Takahashi 1993)

to conduct melting experiments

– X-ray mapping to determine stable

mineral phases of resulting solid

compositions

– Mass spectrometry to measure

incompatible element concentrations

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Bigger Questions

• What solidifies out of this melt?

– Apatite, magnetite, crustal perovskite, post-perovskite,

hematite, corundum, uranium oxides, or something

else?

– Densities?

– Incompatible element enrichment?

• D” layer implications

– Match incompatible element predictions from Carlson &

Boyet (2008)?

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