Bridgmanite's ferric iron content determined Earth's oxidation state

Title data

Wang, Fei ; Wang, Lin ; Fei, Hongzhan ; Miyajima, Nobuyoshi ; McCammon, Catherine ; Frost, Daniel J. ; Katsura, Tomoo:
Bridgmanite's ferric iron content determined Earth's oxidation state.
In: Nature Geoscience. Vol. 18 (2025) . - pp. 670-674.
ISSN 1752-0908
DOI: https://doi.org/10.1038/s41561-025-01725-0

Official URL:

Abstract in another language

Bridgmanite, a magnesium-rich silicate perovskite, is the most prevalent mineral in Earth’s lower mantle and contains substantial quantities of ferric (oxidized) iron, even in equilibrium with iron metal. Mixing of oxygen-rich material from the lower mantle could have raised the oxidation state of the upper mantle to its present level after the more reducing conditions during core formation. However, it remains unclear how the lower-mantle oxygen content was established to achieve this level. Here we use high-pressure and temperature multi-anvil experiments at known oxygen fugacities to show that the bridgmanite ferric iron content is independent of pressure but decreases with temperature. Using these data, we build a thermodynamic model to calculate the ferric iron content of the lower mantle as bridgmanite crystallized from a reduced magma ocean in the early Earth. We determine that this ferric iron content would have been sufficient to explain the current upper mantle’s ferric iron content after whole mantle mixing.

Further data

Item Type:	Article in a newspaper
Refereed:	Yes
Institutions of the University:	Research Institutions > Central research institutes > Bavarian Research Institute of Experimental Geochemistry and Geophysics - BGI
Result of work at the UBT:	Yes
DDC Subjects:	500 Science > 550 Earth sciences, geology
Date Deposited:	02 Jun 2026 07:16
Last Modified:	02 Jun 2026 07:16
URI:	https://eref.uni-bayreuth.de/id/eprint/97809