Acoustic and electrical properties of Fe-Ti oxides with application to the deep lunar mantle

Pommier, Anne; Walter, Michael J.; Hao, Ming; Yang, Jing; Hrubiak, Rostislav

doi:10.1016/j.epsl.2024.118570

Cited by 4 publications

(1 citation statement)

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“…A basal magma ocean could potentially drive a dynamo if it is unstable to convection and has relatively sufficient electrical conductivity due to its molten nature and particularly high Ti and Fe content (Elkins-Tanton et al, 2011;Khan et al, 2014;van Kan Parker et al, 2012;Ziegler & Stegmen, 2013). The electrical conductivity of molten Fe-S alloy-peridotite system or ilmenite can reach 10 4 S/m (Pommier et al, 2024;Yoshino et al, 2004). If KREEP materials sank to the lunar CMB and their electrical conductivity ranged from 10 3 S/m to 2 × 10 4 S/m, a basal magma ocean would generate a magnetic field strength of 12-40 μT (Scheinberg et al, 2018).…”

Section: Lunar Dynamo and Magnetic Fieldmentioning

confidence: 99%

Thermal and Dynamo Evolution of the Lunar Core Based on the Transport Properties of Fe‐S‐P Alloys

Zhai,

Yin,

Zhai

2024

Geophysical Research Letters

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Paleomagnetic analyses have suggested that the lunar magnetic field underwent a significant change from 4.25 to 3.19 Ga, indicating the rapid transition of the lunar dynamo mechanism. We used the van der Pauw (vdP) method to measure the electrical resistivity of Fe‐S‐P alloys under conditions relevant to the lunar core and estimated the thermal conductivity of the Fe‐S‐P lunar core. These values were incorporated into thermal and dynamo models to investigate the evolution of the lunar core. Our model indicates that the inner core began to grow as early as 4.35 Ga, the solidification regime switched at 3.50 Ga, and the thermal dynamo ceased between 3.78 and 3.51 Ga. The cessation of the dynamo could be due to a low buoyancy flux and insufficient entropy dissipation. Thermal and compositional dynamos cannot sustain the ancient strength of the Moon's magnetic field, and require other energy sources.

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