Journal Article

PUBDB-2023-04601

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Compressibility of ferropericlase at high-temperature: Evidence for the iron spin crossover in seismic tomography

Trautner, V. (Corresponding author)Extern* ; Stackhouse, S.Extern* ; Turner, A. R. ; Koelemeijer, P. ; Davies, D. R.Extern* ; Méndez, A. S. J.DESY* ; Satta, N.Extern* ; Kurnosov, A.Extern* ; Liermann, H.-P.XFEL.EU*DESY* ; Marquardt, H.Extern*

2023
Elsevier Amsterdam [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.epsl.2023.118296  doi:10.3204/PUBDB-2023-04601

Abstract: The iron spin crossover in ferropericlase, the second most abundant mineral in Earth's lower mantle, causes changes in a range of physical properties, including seismic wave velocities. Understanding the effect of temperature on the spin crossover is essential to detect its signature in seismic observations and constrain its occurrence in the mantle. Here, we report the first experimental results on the spin crossover-induced bulk modulus softening at high temperatures, derived directly from time-resolved x-ray diffraction measurements during continuous compression of (Mg$_{0.8}$Fe$_{0.2}$)O in a resistive-heated dynamic diamond-anvil cell. We present new theoretical calculations of the spin crossover at mantle temperatures benchmarked by the experiments. Based on our results, we create synthetic seismic tomography models to investigate the signature of the spin crossover in global seismic tomography. A tomographic filter is applied to allow for meaningful comparisons between the synthetic models and data-based seismic tomography models, like SP12RTS. A negative anomaly in the correlation between Vs variations and Vc variations (S-C correlation) is found to be the most suitable measure to detect the presence of the spin crossover in tomographic models. When including the effects of the spin crossover, the misfit between the synthetic model and SP12RTS is reduced by 63%, providing strong evidence for the presence of the spin crossover, and hence ferropericlase, in the lower mantle. Future improvement of seismic resolution may facilitate a detailed mapping of spin state using the S-C correlation, providing constraints on mantle temperatures by taking advantage of the temperature sensitivity of the spin crossover.

Note: Creative Commons licence Attribution 4.0 International (CC BY 4.0)

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Contributing Institute(s):

1. DOOR-User (DOOR ; HAS-User)
2. Experimentebetreuung PETRA III (FS-PET-D)

Research Program(s):

1. 631 - Matter – Dynamics, Mechanisms and Control (POF4-631) (POF4-631)
2. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
3. DEEP-MAPS - Deep Earth Mantle Phase Transition Maps: Studied by Time-Resolved Experiments (864877) (864877)

Experiment(s):

1. PETRA Beamline P02.2 (PETRA III)

Appears in the scientific report 2023

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection ; Zoological Record

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