Abstract
A conspicuous 60° bend of the Hawaiian-Emperor Chain in the north-western Pacific Ocean has variously been interpreted as the result of an abrupt Pacific plate motion change in the Eocene (∼47 Ma), a rapid southward drift of the Hawaiian hotspot before the formation of the bend, or a combination of these two causes. Palaeomagnetic data from the Emperor Seamounts prove ambiguous for constraining the Hawaiian hotspot drift, but mantle flow modelling suggests that the hotspot drifted 4–9° south between 80 and 47 Ma. Here we demonstrate that southward hotspot drift cannot be a sole or dominant mechanism for formation of the Hawaiian-Emperor Bend (HEB). While southward hotspot drift has resulted in more northerly positions of the Emperor Seamounts as they are observed today, formation of the HEB cannot be explained without invoking a prominent change in the direction of Pacific plate motion around 47 Ma.
Highlights
Most geodynamic models predict a drift of the hotspot to the south, and several recent studies argue that a rapid southward motion of the Hawaiian hotspot that ceased at B47 Ma can explain the formation of the Hawaiian-Emperor Bend (HEB) without requiring a significant change in the Pacific plate motion around that time[12,14,23,24]
Kinematic models without a significant change in Pacific plate motion around the time of the bend formation necessitate a large westward component in the total hotspot drift (Fig. 4) that is not supported by geodynamic models (Fig. 5)
The southward hotspot drift that is predicted by these numerical models lacks a significant component of westward motion, reflecting simple flow geometry beneath the northern Pacific region, which is governed by the persistent large-scale upwelling above the Pacific
Summary
The palaeolatitudes from the Emperor Seamounts (Detroit, Suiko, Nintoku and Koko) provide us with a direct record of the southward hotspot motion (B0.42°/Ma) relative to the Earth’s spin axis (Fig. 2), but translating the latitude offsets (15–2°)
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