Volcanic belts are found above zones of unusually high temperature (700 to 1,400 °C (1,292 to 2,552 °F)) where magma is created by partial melting of solid material in the Earth's crust and upper mantle.
It contains over 150 volcanic belts (now deformed and eroded down to nearly flat plains) that range from 600 to 1,200 million years old.
[citation needed] These are zones of variably metamorphosed mafic to ultramafic volcanic sequences with associated sedimentary rocks that form what are known as greenstone belts.
In a sense, subduction zones are the opposite of divergent boundaries, areas where material rises up from the mantle and plates are moving apart.
Canadian geologist John Tuzo Wilson came up with the idea 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, thought to be caused by a narrow stream of hot mantle convecting up from the mantle-core boundary called a mantle plume.
[8] Geologists have identified some 40-50 such hotspots around the globe, with Hawaii, Réunion, Yellowstone, Galápagos, and Iceland overlying the most currently active.