Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: AGU Advances
Most evidence for plate motions in the geological past comes from remnant magnetization of crustal rocks. These indicate progressive changes in latitude with respect to the magnetic dipole. While such paths are often only apparent since relative motions can be explained by continental drift, there is a component of true polar wander. Since spin organizes the convecting core’s geodynamo, polar wander implies motions of the whole Earth with respect to the planet’s rotation axis.
Vaes and van Hinsbergen [2025] provide a reanalysis of paleomagnetic data and find wander rates of approximately 3 centimeters per year, consistent with a smooth response of the moments of inertia to density anomalies shifting within mantle convection. The data cannot rule out faster motions on timescales shorter than approximately 10 million years ago, and there are uncertainties such as due to the non-unique absolute motions of the entire lithosphere with respect to the deep mantle. However, the polar motion paths appear controlled by the connected system of subduction and lowermost mantle anomalies, substantiating earlier suggestions. This system also controls core heat flow, and with it perhaps the nature of the dynamo.
Moreover, some of the deep anomalies have distinct geochemical signatures as seen from plume-sourced hotspots. The geographic links of such reservoirs with the Wilson cycle arise from polar wander as well as absolute and relative plate motions, and the associated interactions remain to be fully integrated in planetary evolution models. Such work is crucial for better estimates of paleoclimate as well as an integrative view of continental geology within the core and mantle components of the Earth system.
Citation: Vaes, B., & van Hinsbergen, D. J. J. (2025). Slow true polar wander around varying equatorial axes since 320 Ma. AGU Advances, 6, e2024AV001515. https://doi.org/10.1029/2024AV001515
—Thorsten Becker, Editor, AGU Advances
Text © 2024. The authors. CC BY-NC-ND 3.0
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