Past plate and mantle motion from new ages for the Hawaiian-Emperor Seamount Chain


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Wilfried.Jokat [ at ] awi.de

Abstract

Estimates of the relative motion between the Hawaiian and Louisville hotspots have consequences for understanding the role and character of deep Pacific-mantle return flow. The relative motion between these primary hotspots can be inferred by comparing the age records for their seamount trails. Our new 40Ar/39Ar ages for 18 lavas from 10 seamounts along the Hawaiian-Emperor Seamount Chain (HESC) show that volcanism started in the sharp portion of the Hawaiian-Emperor Bend (HEB) at �47.5 Ma and continued for �5 Myr (O’Connor et al., 2013). The slope of the along-track distance from the currently active Hawaiian hotspot plotted versus age is remarkably linear between �57 and 25 Ma in the central �1900 km of the seamount chain, including the HEB. This model predicts an age for the oldest Emperor Seamounts that matches published ages, implying that a linear age-distance relationship might extend back to at least 82 Ma. In contrast, Hawaiian age progression was much faster since at least �15 Ma and possibly as early as �27 Ma. Linear age-distance relations for the Hawaii-Emperor and Louisville seamount chains predict �300 km overall hotspot relative motion between 80 and 47.5 Ma, in broad agreement with numerical models of plumes in a convecting mantle, and paleomagnetic data. We show that a change in hotspot relative motion may also have occurred between �55 Ma and �50 Ma. We interpret this change in hotspot motion as evidence that the HEB reflects a combination of hotspot and plate motion changes driven by the same plate/mantle reorganization. O’Connor et al. (2013), Constraints on past plate and mantle motion from new ages for the Hawaiian-Emperor Seamount Chain, Geochem. Geophys. Geosyst., 14, 4564–4584, doi:10.1002/ggge.20267



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Conference (Conference paper)
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Not peer-reviewed
Publication Status
Published
Event Details
European Geosciences Union General Assembly 2014, 27 Apr 2014 - 02 May 2014, Vienna.
Eprint ID
35551
Cite as
O'Connor, J. , Steinberger, B. , Regelous, M. , Koppers, A. , Wijbrans, J. , Haase, K. , Stoffers, P. , Jokat, W. and Garbe-Schönberg, D. (2014): Past plate and mantle motion from new ages for the Hawaiian-Emperor Seamount Chain , European Geosciences Union General Assembly 2014, Vienna, 27 April 2014 - 2 May 2014 .


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