Plate motion and a dipolar geomagnetic field at 3.25 Ga

Alec R. Brenner, Roger R. Fu, Andrew R.C. Kylander-Clark, George J. Hudak, Bradford J. Foley

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


The paleomagnetic record is an archive of Earth’s geophysical history, informing reconstructions of ancient plate motions and probing the core via the geodynamo. We report a robust 3.25-billion-year-old (Ga) paleomagnetic pole from the East Pilbara Craton, Western Australia. Together with previous results from the East Pilbara between 3.34 and 3.18 Ga, this pole enables the oldest reconstruction of time-resolved lithospheric motions, documenting 160 My of both latitudinal drift and rotation at rates of at least 0.55°/My. Motions of this style, rate, and duration are difficult to reconcile with true polar wander or stagnant-lid geodynamics, arguing strongly for mobile-lid geodynamics by 3.25 Ga. Additionally, this pole includes the oldest documented geomagnetic reversal, reflecting a stably dipolar, core-generated Archean dynamo.

Original languageEnglish (US)
Article numbere2210258119
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number44
StatePublished - Nov 1 2022

All Science Journal Classification (ASJC) codes

  • General


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