The petrological evolution of Earth’s solidifying magma ocean from experimental melting phase relations
Abstract
Understanding the crystallisation of silicate melts at lower mantle conditions is essential for constraining the petrological and chemical evolution of planetary magma oceans. In this study, we investigated the solidification of a pyrolitic melt through fractional crystallisation experiments in the laser-heated diamond anvil cell coupled with thermodynamic modelling. Fifteen experiments were conducted to establish the melting phase diagrams of pyrolite at four lower mantle pressures (53, 87, 107, 133 GPa). The data were then used to fit the parameters of a self-consistent thermodynamic model in the FeO-MgO-SiO 2 ternary, which was then applied to calculate the crystallisation sequences of a pyrolitic melt as it solidifies in the deep mantle down to the core-mantle boundary. We confirmed that bridgmanite is the first mineral to crystallise (liquidus phase) in a pyrolitic magma ocean in this entire pressure range, followed by ferropericlase and, in the final stage of crystallisation, calcium silicate perovskite. Our results reveal a strong enrichment of the residual melt in iron oxide, which grows with pressure showing that FeO becomes increasingly incompatible (with depth) in lower mantle phases. The resulting dense, iron-rich melts provide a petrological basis for their accumulation at the base of the mantle, giving rise to a basal magma ocean in the final stages of magma ocean solidification.
Related
- Coupled thermochemical evolution of the early Earth’s solid mantle and basal magma ocean: The role of melting and melt transport
- Statistical discrimination of Guatemalan jadeitite sources using LA-ICP-MS trace element and petrological data
- The most recent volcanic activity of the Manda Hararo rift segment (Central Afar, Ethiopia): new dating and petrological processes associated with the eruption sequences
- Experimental snowball earth viscosity drives the evolution of motile multicellularity
- Experimental evolution in sympatry leads to higher growth rates, but does not alleviate the costs of competition and reproductive interference
BibTeX
@article{gendre2026petrological,
title = {{The petrological evolution of Earth’s solidifying magma ocean from experimental melting phase relations}},
author = {Héloïse Gendre and James Badro and Charles-Édouard Boukaré and Sebastian Cozma and Cécile Hébert and Pau Toruella and Duncan T.L. Alexander and Nicolas Wehr and Stephan Borensztajn},
journal = {Earth and Planetary Science Letters},
year = {2026},
month = sep,
doi = {10.1016/j.epsl.2026.120159},
url = {https://hal.science/hal-05740203v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - The petrological evolution of Earth’s solidifying magma ocean from experimental melting phase relations
AU - Héloïse Gendre
AU - James Badro
AU - Charles-Édouard Boukaré
AU - Sebastian Cozma
AU - Cécile Hébert
AU - Pau Toruella
AU - Duncan T.L. Alexander
AU - Nicolas Wehr
AU - Stephan Borensztajn
PY - 2026
DA - 2026/09/15
JO - Earth and Planetary Science Letters
DO - 10.1016/j.epsl.2026.120159
UR - https://hal.science/hal-05740203v1
AB - Understanding the crystallisation of silicate melts at lower mantle conditions is essential for constraining the petrological and chemical evolution of planetary magma oceans. In this study, we investigated the solidification of a pyrolitic melt through fractional crystallisation experiments in the laser-heated diamond anvil cell coupled with thermodynamic modelling. Fifteen experiments were conducted to establish the melting phase diagrams of pyrolite at four lower mantle pressures (53, 87, 107, 133 GPa). The data were then used to fit the parameters of a self-consistent thermodynamic model in the FeO-MgO-SiO 2 ternary, which was then applied to calculate the crystallisation sequences of a pyrolitic melt as it solidifies in the deep mantle down to the core-mantle boundary. We confirmed that bridgmanite is the first mineral to crystallise (liquidus phase) in a pyrolitic magma ocean in this entire pressure range, followed by ferropericlase and, in the final stage of crystallisation, calcium silicate perovskite. Our results reveal a strong enrichment of the residual melt in iron oxide, which grows with pressure showing that FeO becomes increasingly incompatible (with depth) in lower mantle phases. The resulting dense, iron-rich melts provide a petrological basis for their accumulation at the base of the mantle, giving rise to a basal magma ocean in the final stages of magma ocean solidification.
SN - 0012-821X
ER -