Full-waveform tomography reveals iron spin crossover in Earth lower mantle

Laura Cobden; Jingyi Zhuang; Wenjie Lei; Renata Wentzcovitch; Jeannot Trampert; Jeroen Tromp

doi:10.48550/arXiv.2303.05476

Full-waveform tomography reveals iron spin crossover in Earth lower mantle

Laura Cobden, Jingyi Zhuang, Wenjie Lei, Renata Wentzcovitch, Jeannot Trampert, Jeroen Tromp

Research output: Working paper › Preprint › Academic

Abstract

Joint interpretation of bulk and shear wave speeds constrains the chemistry of the deep mantle. At all depths, the diversity of wave speeds cannot be explained by an isochemical mantle. Between 1000 and 2500 km depth, hypothetical mantle models containing an electronic spin crossover in (Mg,Fe)O provide a significantly better fit to the wave-speed distributions, as well as more realistic temperatures and silica contents, than models without a spin crossover. Below 2500 km, wave speed distributions are explained by enrichment in silica towards the core-mantle-boundary. This silica enrichment may represent the fractionated remains of an ancient basal magma ocean.

Original language	English
Publisher	arXiv
Pages	1-40
Number of pages	40
DOIs	https://doi.org/10.48550/arXiv.2303.05476
Publication status	Published - 9 Mar 2023

Keywords

physics.geo-ph

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10.48550/arXiv.2303.05476

2303.05476v1Submitted manuscript, 5.65 MB

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Full-waveform tomography reveals iron spin crossover in Earth's lower mantle
Cobden, L., Zhuang, J., Lei, W., Wentzcovitch, R., Trampert, J. & Tromp, J., 4 Mar 2024, In: Nature Communications. 15, 1, 10 p., 1961.
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AU - Trampert, Jeannot

AU - Tromp, Jeroen

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AB - Joint interpretation of bulk and shear wave speeds constrains the chemistry of the deep mantle. At all depths, the diversity of wave speeds cannot be explained by an isochemical mantle. Between 1000 and 2500 km depth, hypothetical mantle models containing an electronic spin crossover in (Mg,Fe)O provide a significantly better fit to the wave-speed distributions, as well as more realistic temperatures and silica contents, than models without a spin crossover. Below 2500 km, wave speed distributions are explained by enrichment in silica towards the core-mantle-boundary. This silica enrichment may represent the fractionated remains of an ancient basal magma ocean.

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PB - arXiv

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Full-waveform tomography reveals iron spin crossover in Earth lower mantle

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Full-waveform tomography reveals iron spin crossover in Earth's lower mantle

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