Martian core composition from experimental high-pressure metal-silicate phase equilibria - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Geochemical Perspectives Letters Année : 2022

Martian core composition from experimental high-pressure metal-silicate phase equilibria

H Gendre
James Badro
N Wehr
  • Fonction : Auteur
S Borensztajn
  • Fonction : Auteur

Résumé

Current Martian core composition models suggest an iron-rich core alloyed with 10 to 20 wt. % of sulfur. Although Mars is more oxidised than Earth, oxygen is usually discarded as a potential light element candidate, since its dissolution into iron is negligible at the pressures and temperatures prevailing during Mars's primitive differentiation. However, it has recently been shown that oxygen interacts with the sulfur in the metal, which dramatically increases its solubility. Here, we investigated this novel process by carrying out metal-silicate equilibration experiments between 2 and 12 GPa, and 1673 and 2473 K, using piston-cylinder and multi-anvil presses. The experimental results show that oxygen was systematically incorporated in the metallic phase alongside sulfur, and a thermodynamic model was developed to parametrise this interaction. The oxygen-sulfur interaction parameter arising from those thermodynamic equations was fitted and used in a multi-stage core modelling simulation. We found that a Martian core containing 14 to 19 wt. % S (maximum permissible concentration according to cosmochemical constraints) will also contain between 1.3 and 3.5 wt. % O. This would help to match the Martian core density estimate while being cosmochemically consistent.
Fichier principal
Vignette du fichier
GPL2216_noSI.pdf (1.74 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

hal-03841490 , version 1 (07-11-2022)

Identifiants

Citer

H Gendre, James Badro, N Wehr, S Borensztajn. Martian core composition from experimental high-pressure metal-silicate phase equilibria. Geochemical Perspectives Letters, 2022, 21, pp.42 - 46. ⟨10.7185/geochemlet.2216⟩. ⟨hal-03841490⟩
80 Consultations
43 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More