1. The Geochronology of Hotspot Trails in the Pacific and the Timing of the Hawaii-Emperor Bend Anthony Koppers Scripps Institution of Oceanography, IGPP, San Diego, USA

2. Predictions of the “Fixed Hotspot” Hypothesis Related to Geochronology Constant Angular Plate Velocities –Linear Age Progressions –Consistency in Observed Local Plate Velocities between Multiple Seamount Trails on the Same Tectonic Plate Changes in Plate Motion Should Cause Similar and Synchronous Bends in Multiple Seamount Trails –Same Curvature of Seamount Trails –Same Timing

4. Do we have Different Kinds of Hotspots ? Are Different Processes Involved ? PRIMARY / STRONG Hotspot Trails that are Continuously Active with a Monotonous Age Progression, Flood Basalt Initiation, Deep Mantle 3 He/ 4 He Signature, Large Buoyancy Flux, Low Shear Wave Velocity in Mantle SECONDARY / WEAK Any Other Hotspot Trail that is Typically Short Lived TERTIARY Extensional Features, Like the Puka Puka Ridge Courtillet et al. 2003

5. What I will Cover in the Rest of this Talk … Louisville Seamount Trail as a Primary Hotspot Secondary Hotspots in the West Pacific The Timing of the Hawaii-Emperor Bends in the Gilbert Ridge

24. Conclusions ( I ) The elegant “hotspot” model may (still) explain the primary hotspots such as Hawaii and Louisville, if we allow for significant (inter) hotspot motion However, it seems unable to explain the age distributions and origins of secondary hotspots in the West Pacific

25. Conclusions ( II ) Hotspot motion, the structure of the overlying lithosphere and changing litho- spheric stress regimes may play an important role in the creation of the seamount trails However, no conclusive data exists at this moment to determine which of these processes is the best candidate …