EarthRef.org Digital Archive (ERDA) -- Hotspot and Non-Hotspot Origins for the Age-Distribution of Volcanism in Pacific Seamount

Description
The Hawaiian-Emperor seamount chain is the type example of an age-progressive, hotspot-generated intraplate volcanic lineament. However, our current knowledge of the age distribution within this province is based largely on radiometric ages determined several decades ago. In this keynote presentation during the First SBN Workshop, Bob Duncan shows that major improvements in instrumentation, sample preparation methods and new material obtained by recent drilling warrant a re-examination of the age relations among the older Hawaiian volcanoes. Plateau and isochron age determinations (40Ar-39Ar incremental heating method) on whole rocks and feldspar separates from deep drilling sites (ODP Leg 197) in the Emperor seamounts, together with similarly modern data from dredged rocks from volcanoes near the prominent bend (47-49 Ma) in the lineament (Sharp and Clague, 2002), confirm the overall trend is increasing volcano age from south to north, consistent with the hotspot model. There are important departures from the earlier reported simple linear age progression, which are related to changes in Pacific plate motion and the rate of southward motion of the Hawaiian hotspot. Recent studies of dredged volcanic rocks from the Louisville seamount chain (Koppers et al. 2004) show many of the same features within an overall, age-progressive trend, illustrating the utility of a hotspot reference frame adjusted for slowly advected mantle plumes (Steinberger and O'Connell, 1998).

Project -- Meetings and Workshops -- SBN Workshops
The goal of the Seamount Biogeosciences Network (SBN) is to bring together all the diverse science disciplines involved in seamount research, to communicate about and discuss seamount science, and to explore innovative ways to network amongst the diverse communities working on seamounts.