Paleosecular Variation Constraints on Geomagnetic Field Morphology at ca. 1100 Ma

Abstract Paleosecular variation provides a statistical test of long‐term geomagnetic field morphology, but its behavior across Precambrian polarity regimes remains poorly constrained. We compile a virtual geomagnetic pole dispersion data set spanning 1130–1070 Ma and apply nonlinear Model G fitting to evaluate field structure across the interval associated with the Keweenawan Normal Superchron. The combined data set yields Model G parameters a = 12.54° and b = 0.225, consistent with a broadly geocentric axial dipole‐compatible field at ca. 1100 Ma. When the data set is divided into reversal‐rich pre‐superchron and predominantly single‐polarity superchron intervals, the superchron subset lacks high‐paleolatitude estimates, limiting constraints on the Model G latitude‐dependence parameter b . The split data sets allow a cautious comparison of latitude‐invariant scatter, but they do not resolve polarity‐related changes in field morphology. Our results support substantial axial‐dipole contribution at ca. 1100 Ma and show the present superchron data set cannot robustly test reversal‐dependent latitude structure.