This project is aimed at improving our knowledge of the motion of the Pacific plate, the tectonic plate that lies beneath most of the Pacific Ocean basin, relative to the earth's spin axis over the past 80 million years. The motion relative to the spin axis is determined from the magnetization of the seafloor acquired when it was formed by seafloor spreading. The direction of magnetization will be inferred from an analysis of skewness or shape-symmetry of small spatial variations of the magnetic field observed above Pacific plate seafloor. The results will be applied to several important geologic and geodynamic problems. For example, estimates of Pacific plate motion relative to the spin axis will be compared with motion of the Pacific plate relative to hotspots, such as the Hawaiian hotspot, which leave trails of volcanoes on the Pacific plate. Differences between these two can be used to infer the motion of the hotspots relative to the spin axis, which has important implications for geodynamic processes such as true polar wander and mantle convection.
