Detecting dipolarity of the geomagnetic field in the paleomagnetic record
Jun 13, 2023
Variations in paleomagnetic field strength are key to constraining Earth’s thermal history and characterizing the geodynamo’s energy state. Yet, such inferences strongly depend on the robustness of the absolute paleointensity database. Investigating the correlation between field strength and geomagnetic inclination offers an efficient tool to isolate robust datasets and infer geomagnetic changes. We show that the Cretaceous Normal Superchron, a ~40 Myr interval of stable polarity, may not be associated with enhanced dipolarity of the geodynamo. For times older than 130 Ma, the obtained correlation strength is compatible with the geocentric axial dipole hypothesis, but we stress that seeking distinct dynamo regimes during the Precambrian is currently premature due to the sparsity of high-quality field determinations passing strict selection criteria.