Predictions of the “Fixed Hotspot” Hypothesis Related to Geochronology
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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
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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
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Do we have Different Kinds of Hotspots ? Are Different Processes
Involved ?
• PRIMARY / STRONGHotspot Trails that are Continuously Active with a Monotonous Age Progression, Flood Basalt Initiation, Deep Mantle 3He/4He Signature, Large Buoyancy Flux, Low Shear Wave Velocity in Mantle
• SECONDARY / WEAKAny Other Hotspot Trail that is Typically Short Lived
• TERTIARYExtensional Features, Like the Puka Puka Ridge
Courtillet et al. 2003
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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
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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
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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 …