Gillian Foulger is a leading proponent of the plate hypothesis of volcanism, which posits that volcanism away from plate boundaries can be explained by extensional deformation of the lithosphere with melting of the upper mantle.  The plate hypothesis uses plate tectonic theory to explain all volcanism without invoking plumes or hot-spots that originate in the lower mantle.  She hosts a lively debate on whether mantle plumes exist at mantleplumes.org.

Gillian Foulger is Emerita Professor of Geophysics at Durham University.  A key prediction of the plate hypothesis is that the lithosphere should be extending wherever we see intra-plate volcanism.  She explains that many of the observations we already have can be reinterpreted as consistent with the plate hypothesis, and suggests new experiments that could clearly distinguish the competing hypotheses.

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