Seismic and mineralogical evidence for an iron-rich mega ultralow-velocity zone beneath Hawai'i
File(s)
Published version
Author(s)
Kim, Doyeon
Song, Jung-Hun
Dobrosavljevic, Vasilije V
Lekić, Vedran
Type
Journal Article
Abstract
Mantle plumes beneath major oceanic hotspots appear to be rooted in unusually large structures near the core-mantle boundary, which have dramatically reduced seismic wave speeds. The origin of these large ultralow-velocity zones, referred to as mega-ULVZs, remains uncertain partly due to lack of constraints on the relative reduction in shear vs. compressional wavespeeds (RS/P). This ratio can give clues into the compositional makeup of the mega-ULVZs. Through joint seismic analysis of core-diffracted P- and S-waves beneath Hawai'i, we constrain RS/P of its mega-ULVZ to 1–1.3. Mineralogical modeling reveals that iron enrichment via solid iron-rich magnesiowüstite ((Mg,Fe)O) matches this seismic constraint, independent of modeled ULVZ thickness. Enrichment of metallic iron-rich magnesiowüstite likely enhances the thermal conductivity of mega-ULVZs and provides a mechanism to drive localized plume upwelling. Higher reported RS/P values for smaller ULVZs near subduction zones may therefore indicate different processes at play controlling ULVZ formation across the diverse core-mantle boundary landscape.
Date Issued
2026-01-20
Date Acceptance
2025-12-16
Citation
Science Advances, 2026, 12 (5), pp.1-10
ISSN
2375-2548
Publisher
American Association for the Advancement of Science (AAAS)
Start Page
1
End Page
10
Journal / Book Title
Science Advances
Volume
12
Issue
5
Copyright Statement
© 2026 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY).
License URL
Publication Status
Published
Date Publish Online
2026-01-28