Crustal Melts at the Core-Mantle Boundary

Editors’ Highlights are summaries of recent papers by AGU’s journal editors.

Source: AGU Advances

Seismologists have long known that regions of the lowermost mantle distribute incoming seismic waves in all directions, and this scattering process is indicative of strong lateral gradients of wave speeds and density anomalies.

Thorne et al. [2024] utilize sophisticated, array-based analysis and waveform modeling to convincingly attribute regional bounds and properties to both previously and newly identified scattering regions at the core-mantle boundary. The interpretation is that the scatterers are associated with what has long been denoted as ultralow velocity zones (ULVZs). What is newly emerging is a view of the deep mantle where such features are due to partial melting, likely of subducted oceanic crust, brought down to the proximity of the core by subduction. ULVZs are not stationary or indicative of specific geographic regions, but rather global, dynamic features. Anomalies are being swept around by mantle flow and can constrain the dynamic evolution of the deep mantle. 

Citation: Thorne, M. S., Pachhai, S., Li, M., Ward, J., & Rost, S. (2024). Investigating ultra-low velocity zones as sources of PKP scattering beneath North America and the western Pacific Ocean: Potential links to subducted oceanic crust. AGU Advances, 5, e2024AV001265. https://doi.org/10.1029/2024AV001265

—Thorsten Becker, Editor, AGU Advances

Text © 2024. The authors. CC BY-NC-ND 3.0
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