Extensive iron–water exchange at Earth’s core–mantle boundary can explain seismic anomalies

Kawano, Katsutoshi; Nishi, Masayuki; Kuwahara, Hideharu; Kakizawa, Sho; Inoue, Toru; Kondo, Tadashi

doi:https://doi.org/10.1038/s41467-024-52677-9

Extensive iron–water exchange at Earth’s core–mantle boundary can explain seismic anomalies

Kawano, Katsutoshi; Nishi, Masayuki; Kuwahara, Hideharu et al.

Nature Communications, 2024, 15, 8701

Number of Access:466（2025-08-17 19:38 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/98355

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Title	Extensive iron–water exchange at Earth’s core–mantle boundary can explain seismic anomalies
Creator	CreatorName Kawano, Katsutoshi
	NRID 1000010584120 1000010584120 researchmap permalink 7000015061 7000015061 Scopus Author ID 35272872100 35272872100 CreatorName Nishi, Masayuki
	NRID 1000050505394 1000050505394 CreatorName Kuwahara, Hideharu
	NRID 1000010846819 1000010846819 CreatorName Kakizawa, Sho
	NRID 1000000291500 1000000291500 CreatorName Inoue, Toru
	NRID 1000020252223 1000020252223 researchmap permalink read0191570 read0191570 Scopus Author ID 36092955800 36092955800 CreatorName Kondo, Tadashi
Description	Kawano K., Nishi M., Kuwahara H., et al. Extensive iron–water exchange at Earth’s core–mantle boundary can explain seismic anomalies. Nature Communications 15, 8701 (2024); https://doi.org/10.1038/s41467-024-52677-9.
Abstract	Seismological observations indicate the presence of chemical heterogeneities at the lowermost mantle, just above the core–mantle boundary (CMB), sparking debate over their origins. A plausible explanation for the enigmatic seismic wave velocities observed in ultra-low-velocity zones (ULVZs) is the process of iron enrichment from the core to the silicate mantle. However, traditional models based on diffusion of atoms and penetration of molten iron fail to account for the significant iron enrichment observed in ULVZs. Here, we show that the chemical reaction between silicate bridgmanite and iron under hydrous conditions leads to profound iron enrichment within silicate, a process not seen in anhydrous conditions. Our findings suggest that the interaction between the core and mantle facilitates deep iron enrichment over a few kilometres at the bottom of the mantle when water is present. We propose that the seismic signatures observed in ULVZs indicate whole mantle convection, accompanied by deep water cycles from the crust to the core through Earth’s history.
Publisher	Nature Research
Source Title	Nature Communications
Volume (Issue)	15
Page	8701
Date of Issued	2024-10-15
Language	English
Handle URL	https://hdl.handle.net/11094/98355
eISSN	20411723
Relation.isIdenticalTo	DOI (Publisher Version) https://doi.org/10.1038/s41467-024-52677-9
Access Rights	open access
CopyRight	This article is licensed under a Creative Commons Attribution 4.0 International License.
oaire:version	Version of Record
Category	学術雑誌論文 Journal Article

Resource Type	journal article
Local Type	Journal Article
DCTERMS.bibliographicCitation	Nature Communications. 2024, 15, p. 8701
DC.title	Extensive iron–water exchange at Earth’s core–mantle boundary can explain seismic anomalies
DC.creator	Kawano, Katsutoshi
	Nishi, Masayuki
	Kuwahara, Hideharu
	Kakizawa, Sho
	Inoue, Toru
	Kondo, Tadashi
DC.publisher	Nature Research
DC.language' scheme='DCTERMS.RFC1766	English
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2024-10-15
DC.identifier	https://doi.org/10.1038/s41467-024-52677-9
DC.description	Kawano K., Nishi M., Kuwahara H., et al. Extensive iron–water exchange at Earth’s core–mantle boundary can explain seismic anomalies. Nature Communications 15, 8701 (2024); https://doi.org/10.1038/s41467-024-52677-9.
DCTERMS.abstract	Seismological observations indicate the presence of chemical heterogeneities at the lowermost mantle, just above the core–mantle boundary (CMB), sparking debate over their origins. A plausible explanation for the enigmatic seismic wave velocities observed in ultra-low-velocity zones (ULVZs) is the process of iron enrichment from the core to the silicate mantle. However, traditional models based on diffusion of atoms and penetration of molten iron fail to account for the significant iron enrichment observed in ULVZs. Here, we show that the chemical reaction between silicate bridgmanite and iron under hydrous conditions leads to profound iron enrichment within silicate, a process not seen in anhydrous conditions. Our findings suggest that the interaction between the core and mantle facilitates deep iron enrichment over a few kilometres at the bottom of the mantle when water is present. We propose that the seismic signatures observed in ULVZs indicate whole mantle convection, accompanied by deep water cycles from the crust to the core through Earth’s history.
DC.rights	This article is licensed under a Creative Commons Attribution 4.0 International License.
DC.format	98355
citation_title	Extensive iron–water exchange at Earth’s core–mantle boundary can explain seismic anomalies
citation_author	Kawano, Katsutoshi
	Nishi, Masayuki
	Kuwahara, Hideharu
	Kakizawa, Sho
	Inoue, Toru
	Kondo, Tadashi
citation_publisher	Nature Research
citation_language	English
citation_date	2024-10-15
citation_journal_title	Nature Communications
citation_volume	15
citation_firstpage	8701
citation_doi	https://doi.org/10.1038/s41467-024-52677-9
citation_public_url	https://hdl.handle.net/11094/98355

Extensive iron–water exchange at Earth’s core–mantle boundary can explain seismic anomalies

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