Abstract The long‐term variation of the geomagnetic field is a key constraint for unraveling the geodynamo processes and the evolution of Earth's deep interior. However, the geomagnetic reversal pattern during the Ediacaran–Cambrian transition remains elusive. Here we present an integrated magneto‐ and cyclo‐stratigraphic study of a ∼1.8‐Myr‐long, late Ediacaran succession in Newfoundland, Canada. We obtained a reversal frequency of 10–12 Myr −1 , documenting a hyperactively reversing geodynamo during the late Ediacaran. Together with the updated reversal records and paleointensity data sets, we propose a >70‐Myr‐long interval of geomagnetic reversal hyperactivity before the Ordovician Reversed Superchron, forming a hyperactivity‐superchron couplet that recurs in the mid‐Paleozoic and Mesozoic. These findings suggest that the onset of the ∼200‐Myr‐long cycle in geomagnetic field behavior has occurred since at least ∼570 Ma, earlier than previously envisaged.
Shen et al. (2025) studied this question.