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Kilometer-scale structure on the core–mantle boundary near Hawaii

Li, Zhi; Leng, Kuangdai; Jenkins, Jennifer; Cottaar, Sanne

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Authors

Zhi Li

Kuangdai Leng

Sanne Cottaar



Abstract

The lowermost mantle right above the core-mantle boundary is highly heterogeneous containing multiple poorly understood seismic features. The smallest but most extreme heterogeneities yet observed are ‘Ultra-Low Velocity Zones’ (ULVZ). We exploit seismic shear waves that diffract along the core-mantle boundary to provide new insight into these enigmatic structures. We measure a rare core-diffracted signal refracted by a ULVZ at the base of the Hawaiian mantle plume at unprecedentedly high frequencies. This signal shows remarkably longer time delays at higher compared to lower frequencies, indicating a pronounced internal variability inside the ULVZ. Utilizing the latest computational advances in 3D waveform modeling, here we show that we are able to model this high-frequency signal and constrain high-resolution ULVZ structure on the scale of kilometers, for the first time. This new observation suggests a chemically distinct ULVZ with increasing iron content towards the core-mantle boundary, which has implications for Earth’s early evolutionary history and core-mantle interaction.

Citation

Li, Z., Leng, K., Jenkins, J., & Cottaar, S. (2022). Kilometer-scale structure on the core–mantle boundary near Hawaii. Nature Communications, 13(1), https://doi.org/10.1038/s41467-022-30502-5

Journal Article Type Article
Acceptance Date Apr 28, 2022
Online Publication Date May 19, 2022
Publication Date 2022
Deposit Date Aug 1, 2022
Publicly Available Date Mar 29, 2024
Journal Nature Communications
Publisher Nature Research
Peer Reviewed Peer Reviewed
Volume 13
Issue 1
DOI https://doi.org/10.1038/s41467-022-30502-5

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Publisher Licence URL
http://creativecommons.org/licenses/by/4.0/

Copyright Statement
This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.




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