The late Ediacaran to early Cambrian was marked by significant biological and geochemical transformations, including the diversification of animal life, and an enigmatic paleomagnetic record. This study focuses on the Nama Group, a key geological unit for understanding the Ediacaran-Cambrian transition, yet hampered by limited paleogeographic constraints. Previous paleomagnetic studies identified complex remagnetization patterns but lacked a detailed examination of remanence carriers. To address this, we conducted field stability tests and employed advanced rock magnetic techniques on unweathered borehole core samples to complement paleomagnetic data. Thermal demagnetization identified three magnetic components. C1 is a present-day field viscous remanent magnetization (VRM) and was used for borehole core orientation. C2, carried by single domain (SD) pyrrhotite and SD magnetite, aligns with early Paleozoic remagnetization poles from West Gondwanaland and was likely acquired through a thermoviscous magnetization (TVRM) in magnetite and a thermoremanent magnetization (TRM) in pyrrhotite, suggesting regional uplift and cooling between 500-480 Ma. This quasi-synchronous remagnetization is supported by highly clustered paleomagnetic poles and thermochronological data. C3 is an anomalous component with significant inclination variation within the stratigraphy, carried by large pseudo-single domain (PSD) magnetites, possibly of primary, detrital origin. The pattern resembles findings from other cratons, suggesting an unstable geomagnetic field that could have persisted until ca. 540 Ma. This may represent one of the youngest occurrences of such extreme geomagnetic instability in the Ediacaran and provides the first evidence of this behavior in the Kalahari Craton, adding new support for a largely unstable geomagnetic field during this period.

Inclination is the angle of a magnetization vector from horizontal. Clastic sedimentary rocks often experience inclination shallowing whereby syn- to post-depositional processes result in flattened detrital remanent magnetizations relative to local geomagnetic field inclinations. The deviation of recorded inclinations from the true values presents challenges for reconstructing paleolatitudes. A widespread approach for estimating the flattening factor ($f$) compares the shape of an assemblage of magnetization vectors to that derived from a paleosecular variation model (the elongation/inclination [$E/I$] method). However, few studies exist that compare the results of this statistical approach with empirically determined flattening factors and none in the Proterozoic Eon. In this study, we evaluate inclination shallowing within 1.1 billion-year-old, hematite-bearing, interflow red beds of the Cut Face Creek Sandstone that is bounded by lava flows of known inclination. We found that detrital hematite remanence is flattened with f = 0.65{0.75}_{0.56}$ whereas the pigmentary hematite magnetization shares a common mean with the volcanics. Comparison of detrital and pigmentary hematite directions results in $f = 0.61^{0.67}_{0.55}$. These empirically determined flattening factors are consistent with those estimated through the $E/I$ method ($f = 0.64^{0.85}_{0.51}$) supporting its application in deep time. However, all methods have significant uncertainty associated with determining the flattening factor. This uncertainty can be incorporated into the calculation of paleomagnetic poles with the resulting ellipse approximated with a Kent distribution. Rather than seeking to find “the flattening factor,’ or assuming a single value, the inherent uncertainty in flattening factors should be recognized and incorporated into paleomagnetic syntheses.