The elusive mantle plume
Jeroen Ritsema a;Ã
, Richard M. Allen b
Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, USA
Department of Geology and Geophysics, University of Wisconsin, Madison, WI 53706, USA
Received 3 November 2002; received in revised form 18 November 2002; accepted 20 November 2002
Mantle plumes are hypothetical hot, narrow mantle upwellings that are often invoked to explain hotspot volcanism
with unusual geophysical and geochemical characteristics. The mantle plume is a well-established geological structure
in computer modeling and laboratory experiments but an undisputed seismic detection of one has yet to be made.
Vertically continuous low shear velocity anomalies in the upper mantle, expected for plumes, are present beneath the
Afar, Bowie, Easter, Hawaii, Iceland, Louisville, McDonald, and Samoa hotspots but not beneath the other 29
hotspots in Sleep's 1990 catalog. Whether and how plumes form remain fundamental multi-disciplinary research
questions. Should they exist, detection of whole-mantle plumes will depend on deployments of dense (50^100 km
station spacing), wide-aperture ( s 1000 km) seismic networks to maximize model resolution in the transition zone and
uppermost lower mantle since plume impingement upon the 660-km phase transition leaves a unique seismic imprint.
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