Emplacement of a mantle plume

Mantle plumes initiate at the core-mantle boundary and rise through the convective mantle. Upon approaching the more rigid lithosphere, they spreads laterally under the lithosphere. They may also thermally erode to base of the lithosphere and spread higher up. This is equivalent to put a hot layer, a few tens of kilometre thick, underneath or within the colder lithosphere. In the Archaean, the Earth was warmer and plumes were most likely more numerous. The graphs below document the thermal impact of a mantle plume assuming that the plume's head spreads into a 50km thick layer with a temperature of 1700ºC. The three graphs show the results for various depth of emplacement.

Learn more by reading the following paper: Rey et al, 2003