Application of High Precision 40Ar/39Ar Geochronology to Volcanoes of the Hawaiian-Emporeror Chain

Berkeley Geochronology Center, Berkeley CA

Investigators

Abstract

Award is for 40 Ar/39 Ar incremental heating re-dating of previously-collected lava samples from the Hawaiian-Emperor seamount chain to more precisely determine its volcanic evolution. This seamount chain represents the "trace" of excess volcanism associated with the Hawaiian plume, showing how the Pacific Plate has moved relative to the plume, most likely of deep mantle origin. Previous whole-rock K-Ar dates of these samples are too imprecise to address fundamental questions about whether the Hawaiian plume, the most important and largest plume on earth, is fixed relative to the earth's mantle. The more precise 40 Ar/39 Ar incremental heating dates will allow for more precise resolution of plume location and Hawaiian-Emperor volcanism and edifice-building with time, resolution needed to accurately compare the Hawaiian-Emperor chain end with other tectonic features of the Pacific plate and to fundamentally address the issue of whether this plume has moved relative to the mantle in its history.