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- Title
A diamond-bearing core-mantle boundary on Mercury.
- Authors
Xu, Yongjiang; Lin, Yanhao; Wu, Peiyan; Namur, Olivier; Zhang, Yishen; Charlier, Bernard
- Abstract
Abundant carbon was identified on Mercury by MESSENGER, which is interpreted as the remnant of a primordial graphite flotation crust, suggesting that the magma ocean and core were saturated in carbon. We re-evaluate carbon speciation in Mercury's interior in light of the high pressure-temperature experiments, thermodynamic models and the most recent geophysical models of the internal structure of the planet. Although a sulfur-free melt would have been in the stability field of graphite, sulfur dissolution in the melt under the unique reduced conditions depressed the sulfur-rich liquidus to temperatures spanning the graphite-diamond transition. Here we show it is possible, though statistically unlikely, that diamond was stable in the magma ocean. However, the formation of a solid inner core caused diamond to crystallize from the cooling molten core and formation of a diamond layer becoming thicker with time. A diamond layer that becomes thicker with time is generated from carbon exsolution at the core-mantle boundary of Mercury, owing to cooling of its metallic core and potentially the silicate magma ocean.
- Subjects
CORE-mantle boundary; PLANETARY interiors; SIDEROPHILE elements; MERCURY; MERCURY (Planet); DIAMONDS; LIQUIDUS temperature
- Publication
Nature Communications, 2024, Vol 15, Issue 1, p1
- ISSN
2041-1723
- Publication type
Article
- DOI
10.1038/s41467-024-49305-x