The Earth — a Heat Engine

Abstract

The terrestrial mantle is continuously pervaded by slow movements (convection) which transfer the internal heat of the Earth to its surface and reheat the cold plates plunging along the subduction zones, which thus play a key role in the control of this circulation. The oceanic ridges are not necessarily located right above the zones of ascent of these convection cells. The hot-spots, areas of particularly strong volcanism, are fed by jets of hot mantle, the so-called plumes, in which rapid upward movements account for an important part of the heat transfer to the surface. Hotspots are located either on ridges, e. g. the Iceland ridge or within plates, e. g. Hawaii.