PALEOMAGNETIC EVIDENCE FOR MOTION OF THE HAWAIIAN HOTSPOT DURING FORMATION OF THE EMPEROR SEAMOUNTS

The bend in the Hawaiian-Emperor chain is the best example of a change in plate motion recorded in a fixed-hotspot frame of reference. Alter natively, the bend might record primarily differences in motion of the Hawaiian hotspot relative to the Pacific lithosphere. New paleomagnet ic data from the Emperor chain support the latter view. Although the r ate of motion is difficult to constrain because of uncertainties posed by true polar wander and limited sampling of the chain, the best avai lable paleomagnetic data suggest Pacific hotspots may have moved at ra tes comparable to those of lithospheric plates (> 30 mm yr(-1)) in lat e Cretaceous to early Tertiary times (81-43 Ma). If correct, this requ ires a major change in how we view mantle dynamics and the history of plate motions. In the early to mid-Cretaceous (128-95 Ma), hotspots in the Atlantic moved at similar rates. These episodes during which grou ps of hotspots appear to move rapidly are separated by times of much s lower motion, such as the past 5 m.y. (C) 1997 Elsevier Science B.V.