Deep Origin of Hotspots--the Mantle Plume Model

Many volcanoes are associated with subduction zones or mid-ocean ridges, but other areas of unusually high volcanism (or hotspots) do not have such a direct connection to plate tectonic processes. DePaolo and Manga argue in their Perspective that some hotspots are caused by narrow upwelling plumes originating in the lower mantle, while others are caused by broad, hot upwellings or Yet others are not obviously associated with either deep plumes or superswells. Direct evidence for mantle plumes will require seismic imaging at higher resolution than is currently accessible. In a related Perspective, Foulger and Natland take the opposing view that hotspot volcanism is a by-product of plate tectonics and does not require deep plumes.