Sediment thickness anomalies suggest ~1 degree movement of Pacific hotspots in the Miocene

What is it about?

Working out the detailed paleolatitude history of the Pacific tectonic plate is complicated by potential movement of the hotspots that are commonly used as a reference to measure the plate movement. Furthermore, paleomagnetic estimates are limited and have large uncertainties. The location of the paleo-equator was estimated in the present article from anomalously thick sediment found in seismic reflection traverses of the equatorial Pacific sediment bulge, combined with geochemical tracers of high equatorial productivity (Al, Ba and P measurements on cores). The significance of this location is complicated by how sharply varying the sedimentation can be expected to have been about the equator, thus needing independent verification for example from paleomagnetic measurements. Nevertheless, at face value a comparison with hotspots-based reconstructions suggests that the Pacific hotspots moved ~1 degree northward prior to 9.3 Ma and then subsequently reversed that movement towards the present day.

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