Linking the Late Cretaceous to Paleogene Pacific plate and the Atlantic bordering continents using plate circuits and paleomagnetic data

Abstract

Late Cretaceous to Paleogene paleomagnetic data from the Pacific plate (the Emperor Seamounts) can be compared with data from the Atlantic bordering continents through the use of plate circuit reconstructions. Here we summarize the uncertainties in all data sets and present formal tests. We report agreement between Late Cretaceous Pacific paleomagnetic data and predictions based on the estimates of non‐Pacific pole positions from synthetic apparent polar wander paths. This congruency points to the veracity of the plate circuits and the accuracy of the paleomagnetic estimates. In contrast to the agreement seen for the Late Cretaceous, small discrepancies are observed in the comparisons of the Pacific Paleogene data and predictions from synthetic apparent polar wander paths. Such a disparity in a younger time interval is unexpected, given the agreement of the Late Cretaceous data. The possibility that minor, temporally variable nondipole field components contribute to the discrepancy cannot be completely discounted. However, an alternative and more straightforward explanation is suggested by further comparisons of the mean non‐Pacific paleomagnetic data and the highest‐quality poles that contribute to the means. In particular, we note that (1) the Pacific Paleogene data are in full agreement with coeval poles from North America meeting strict reliability criteria and (2) the non‐Pacific Paleogene poles of synthetic apparent polar wander paths are dominated by results from the North Atlantic Igneous Province (NAIP), but taken as a whole, the NAIP data fail a paleomagnetic reversal test. Hence, minor discrepancies between Paleocene paleomagnetic data from the Pacific and Atlantic hemispheres may point to limitations of the latter, which incorporate a relatively large number of older, lower‐quality data. These findings call for renewed data collections utilizing comprehensive rock magnetic and paleomagnetic (demagnetization) procedures to improve resolution of Paleocene non‐Pacific data. The uncertainties of the Pacific paleolatitude data and the non‐Pacific reference poles are larger than the differences related to the use of the two alternative plate circuits (through East to West Antarctica and through Australia to the Lord Howe Rise) that link the Atlantic and Pacific hemispheres. While no preference can thus be given to either plate circuit, their overall consistency with paleomagnetic data suggests that they can be used to investigate long‐term motion of the Pacific plate since Late Cretaceous times.