Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Solid Earth
Seismologists have long detected unusual structures deep beneath continents at mid-lithospheric depths (80–120 kilometers), but their cause has remained uncertain.
In a new study, Zhang et al. [2025] use state-of-the-art computer simulations that combine first-principles (or fundamental assumption) calculations with machine learning to discover a new form of calcium carbonate, an important carbon-bearing mineral in Earth’s deep interior. This newly identified phase undergoes remarkable elastic softening under mid-lithospheric conditions, greatly reducing seismic wave speeds. Even trace amounts of such carbonate could explain the puzzling seismic signals and anomalous electrical properties observed beneath ancient continental regions.
These findings suggest that carbonates play a far more important role in shaping continental structure than previously recognized. Moreover, the results demonstrate that advanced computational methods can uncover unexpected aspects of the deep carbon cycle and the long-term stability of continental roots.
Citation: Zhang, P., Man, L., Yuan, L., Wu, X., & Zhang, J. (2025). Ultra-low-velocity disordered CaCO3 may explain mid-lithospheric discontinuities. Journal of Geophysical Research: Solid Earth, 130, e2025JB031906. https://doi.org/10.1029/2025JB031906
—Jun Tsuchiya, Editor, JGR: Solid Earth
Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.
Related