Mantle Plume Theory
It is believed that a mantle plume underlies Iceland, of which the hotspot is thought to be the surface expression. This enhances the volcanism already caused by plate separation, both at the centre of the island and at the Reykjanes ridge to the southwest of Iceland's main volcanic zone. The plume is believed to be quite narrow, perhaps 100 km across, and extends down to at least 400–650 km beneath the Earth's surface, and possibly down to the core-mantle boundary.
Studies suggest that the hotspot is only 50-100 K hotter than its surroundings, which may not be a great enough difference to drive a buoyant plume.
It is suggested that the lack of a time-progressive track is because the plume may have been located beneath the thick Greenland craton for a significant time.
Other articles related to "mantle plume, mantle, plume":
... of the Monteregian Hills might be due either to failure of the New England mantle plume to pass through massive strong rock of the Canadian Shield, the lack of noticeable ... The other explanation for their origin is they formed above a mantle plume associated with the Canary or Azores hotspots in the Atlantic Ocean, based on the existence of older ...
... At the base of the lithosphere (the layer of crust and upper mantle that forms Earth's moving tectonic plates) ... is that a hot spot, an extremely hot plume of deep mantle material, is rising to the surface beneath the Columbia Plateau Province ... instability develops (for reasons not yet well understood) at the boundary between the core and mantle ...
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