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Updated: May 16, 2025
06:04
Simulation of the Planetary Interior Differentiation Processes in the Laboratory
Published on: November 15, 2013
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Percolative sulfide core formation in oxidized planetary bodies.
Samuel D Crossley1,2,3, Jacob B Setera4, Brendan A Anzures5
1NASA Johnson Space Center, 2101 NASA Parkway, Houston, TX, 77058, USA. crossley@arizona.edu.
Nature Communications
|April 4, 2025
Summary
Planetary core formation may involve sulfide melts migrating before rock melting, especially in oxidized bodies. This process explains noble metal distributions in meteorites and suggests sulfide cores for planets like Mars.
Area of Science:
- Planetary Science
- Geochemistry
- Mineral Physics
Background:
- Planetary core formation models typically assume metal-silicate separation after silicate melting.
- Oxidized conditions and abundant sulfur favor iron-nickel sulfide stability over metal.
- This is particularly relevant for bodies forming in the outer solar system.
Purpose of the Study:
- To investigate percolative sulfide melt migration in primitive, oxidized mineral assemblages.
- To determine the role of sulfide fractionation in noble metal distribution.
- To assess implications for the core composition of oxidized planetary bodies.
Main Methods:
- Partial melting experiments using meteorite samples.
- Experiments with partially molten synthetic sulfides.
- Analysis of noble metal (Os, Ru, Ir, Pd, Pt) trace element proportions.
Main Results:
- Percolative sulfide melt migration observed in primitive, oxidized mineral assemblages prior to silicate melting.
- Fractionation of liquid sulfide from solid residues yields distinct noble metal proportions.
- These proportions match those found in oxidized meteoritic residues (brachinites) and their complementary melts.
Conclusions:
- Provides robust evidence for percolative sulfide melt fractionation in meteorites.
- Suggests that sulfide-dominated cores are expected in oxidized planetary bodies.
- This mechanism offers a new perspective on planetary core formation, including for Mars.
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