Toward finer resolution APWPs

Abstract

Our understanding of paleogeography through Earth history relies heavily on apparent polar wander paths (APWPs), which represent the time-dependent position of Earth’s spin axis relative to a given tectonic plate. However, there are a number of limitations associated with conventional approaches to APWP construction. First, the paleomagnetic record contains significant uncertainty in individual pole positions that is not propagated into APWPs. This traditional approach makes it difficult to incorporate age and positional uncertainty into synthesized paths and assigns equal weight to paleomagnetic poles with vastly different numbers of underlying sites. Second, the effective propagation of site-level uncertainties into the APWP requires a transformation that renders traditional parametric assumptions (i.e., Fisher statistics) on the pole level ineffective. Here, we overcome these limitations with a bottom-up Monte Carlo uncertainty propagation scheme that operates on site-level paleomagnetic data. To demonstrate our methodology, we present a large compilation of site-level Cenozoic paleomagnetic data from North America, which we use to generate a high-resolution APWP. We show that even in the presence of significant noise, polar wandering can be assessed with unprecedented temporal and spatial resolution.