Abstract:
Abundant paleopole information for the Pacific plate exists from the paleomagnetism of DSDP basalts and sediments, the magnetization of seamounts, the position of ancient equators inferred from marine geology, and the skewness of magnetic anomaly profiles. We have combined these data to obtain the apparent polar wander path for the Pacific plate since the Early Cretaceous, using non-linear least squares and maximum likelihood statistics. The data and their uncertainties are input and the best fit pole position, confidence limits and data importances are output. For the Late Cretaceous the amount of data available is great enough to permit tests for statistical stability and consistency between different types of data. The poles determined from the paleomagnetism of DSDP basalts and sediments show excellent internal consistency and are concordant with the paleomagnetism of upper Cretaceous seamounts. The pole determined from paleoequators is not well defined but is consistent with the DSDP paleomagnetism and seamount poles. This suggests that Tertiary paleo-equator data may be combined with the sparse Tertiary paleomagnetic data to obtain Cenozoic paleopoles. The pole inferred from the intersection of Late Cretaceous anomaly skewness lunes is not consistent with the other paleomagnetic poles. We speculate that the anomalous skewness from Late Cretaceous anomalies in the south Pacific may lie entirely in the Pacific plate anomalies and not in the Antarctic plate anomalies. Between the Early and Late Cretaceous the amount of polar wander is small and is consistent with slow northward motion of the Pacific plate. The latest Cretaceous pole is consistent with the fixed hotspot hypothesis.