Absolute migration of Pacific basin mid-ocean ridges since 85 Ma and tectonics in the circum-Pacific region

Abstract

We have investigated the absolute migration of mid-ocean ridges in the Pacific basin since 85 Ma and their tectonic implications. Our results indicate that ridges in the northern and central Pacific basin and those in the southern Pacific basin underwent different tectonic histories. The northern and central Pacific basin ridges do not show any change in absolute migration direction at the time of the Hawaii-Emperor chain bend, while the southern Pacific basin ridges changed their absolute migration direction at Chron 21 (the time of the bend). These results imply that tectonic events in southern Pacific basin may be more localised. The migration of the southern Pacific basin ridges may record the reorganisation of the southern Pacific triple junction or an episode of Cenozoic East-West separation of Antarctica and the initiation of seafloor spreading in the Adare basin, or a combination of the two events. Furthermore, the clockwise rotation of the Pacific plate since Chron 34 ended at Chron 6, after which the Pacific plate has migrated in a north-westerly direction without rotating. © 2011 The Royal Society of New Zealand.