Intraplate processes
The first formulation of plate tectonics argued that volcanic and seismic events are concentrated at plate boundaries, but it soon became clear that the inside plates are unique tectonic and magmatic processes, which were also interpreted within the framework of this theory. Among intraplate processes of the special place occupied the long-term effects of basaltic magmatism in some areas, the so-called hot spots.
Hotspots
At the bottom of the oceans are numerous volcanic islands. Some of them are located in chains with consistently changing age. A classic example of such a submarine ridge became Hawaiian underwater ridge. He rises above the ocean surface in the form of the Hawaiian Islands, from which the north-west is a chain of seamounts with continuously increasing age, some of which, such as Midway, come to the surface. At a distance of about 3000 km from Hawaii, a chain of little turns north and is called the Imperial range. He was suspended in the deep-sea trenches in front of the Aleutian island arc.
To explain this amazing structure was assumed that under the Hawaiian Islands are a hot spot - the place where the surface rises hot mantle flow, which moves over them proplavlyaet oceanic crust. Such points are found on Earth set. Mantle flow, which causes them, was named plume. In some cases it is assumed only a deep origin of matter plumes up to the boundary core - mantle.