Is the Origin of Hawaii as Fixed as its Plume

In 2002, paleolatitude data led researchers from the Ocean Drilling Program to investigate whether the Hawaiian Emperor Bend resulted from a moving hotspot and/or true polar wander as opposed to forming solely as a result of plate movement. In 1963 J. Tuzo Wilson had proposed that the bend was caused by a change in direction of plate movement over the hotspot. With new findings and more extensive evidence, scientists are re-evaluating mantle plumes and plate movements. In 1995, researchers cored basalts from the Detroit Seamount. Researchers drilled as many seamounts as possible to determine their paleolatitude; basalt storage of magnetic minerals provides fairly accurate historical evidence of Earth’s past magnetic fields. The Detroit Seamounts basalts suggest that the bend did not form where Hawaii is presently located, at 19 degrees latitude; it must have formed between 30-35 degrees latitude. This suggests that true polar wander and plate movement contributed to the formation of the Hawaiian Emperor Bend. The data collected from the drilling supports the notion that between 80-45 millions ago, when the Emperor Seamount was forming, the Hawaiian hotspot was moving south between 30-20 degrees latitude but halted, and subsequently the plate began shifting north to northwest, which explains the bend (Pinsker, 2003). On the other hand, researcher Warren Sharp from the Berkeley Geochronology Center has reconstructed the time of the bend to have occurred 46-49 million years ago. This would have been during the Cretacious period when true polar wander was present because of plate movement around the Pacific basin (ODP Publications, 2003). If the theory that all hotspots are fixed is true, then the Pacific plate would have been moving towards the northern rim of the Pacific, meaning that the Pacific basin would have undergone the same effects as the bend (Pinsker, 2003). However other seamount formations of the Pacific plate did not undergo this effect (i.e. the Pitcairn Islands). Despite some geologists’ rebuttal of the theory of moving hotspots, these findings have real significance in reconstructing the history of the north Pacific: unveiling the consequences of mantle convection, moving plates, and the possibility of moving mantle plumes.