Hotspot (geology)

An example of mantle plume locations suggested by one recent group.

World map showing the locations of prominent hotspots. 1) Divergent plate boundaries 2) Transform plate boundaries 3) Convergent plate boundaries 4) Plate boundary zones 5) Selected prominent hotspots

Diagram showing a cross section though the Earth's lithosphere (in yellow) with magma rising from the mantle (in red).

In geology, a hotspot or hot spot is a portion of the Earth's surface which experiences volcanism. This may be caused by a rising mantle plume or some other cause. Hotspots may be far from tectonic plate boundaries.

A volcanic hotspot is where lava pushes up from under the mantle and creates a volcano. The earth's plates move along and another volcano is created later. This creates a chain of volcanoes, such as in Hawaii.

Discussion

J. Tuzo Wilson suggested in 1963 that volcanic chains like the Hawaiian Islands result from the slow movement of a tectonic plate across a fixed hot spot deep beneath the surface of the planet. Hotspots are thought to be caused by a narrow stream of hot mantle convecting up from the Earth's core–mantle boundary called a mantle plume, although some geologists prefer upper-mantle convection as a cause.

Geologists have identified some 40–50 such hotspots around the globe. Those under Hawaii, Réunion, Yellowstone, Galápagos Islands, are the most active at present.