A weighted least-squares fit of the Australian apparent polar wander path for the last 100 Myr

Abstract

Summary. Recent versions of the Australian apparent polar wander path (APWP) for the late Mesozoic and Tertiary show considerable variation. Re-examination of the Australian igneous data suggests that they are more reliable than assumed by some recent authors. The trajectory of the Australian APWP is defined by fitting the position of a set of poles including both igneous and laterite/overprint data. This allows the dated igneous poles to be used to determine age as a function of distance along the trajectory. Both the trajectory and the age are fitted by means of weighted least-squares regression, and are given approximate confidence limits. Age is best fitted in the Australian case as a linear function of distance along the APWP. This result contrasts with that of Idnurm, who suggested a variable rate of polar wander during the Tertiary. The new APWP is in better agreement with hot-spot data. Dating of New Caledonian laterites by the new APWP gives a result consistent with geological evidence, while dating by reference to Idnurm's path does not. Large non-dipole components or significant true polar wander are not needed to explain the Australian Tertiary APWP.