listing possible hotspots, distinction is made between primary hotspots coming from deep within the mantle (possibly originating from the core/mantle boundary), creating large volcanic provinces with linear tracks (Easter Island, Iceland, Hawaii, Afar, Louisville, Reunion, Tristan confirmed, Galapagos, Kerguelen and Marquersas likely) and secondary hotspots derived from mantle plumes (Samoa, Tahiti, Cook, Pitcairn, Caroline, MacDonald confirmed, up to about 20 possible) at the upper/lower mantle boundary that do not form large volcanic provinces but form island chains. Īt any place where volcanism is not linked to a constructive or destructive plate margin, the concept of a hotspot has been used to explain its origin. Whether or not such mantle plumes exist is the subject of a major controversy in Earth science. It was later postulated that hotspots are fed by narrow streams of hot mantle rising from the Earth's core–mantle boundary in a structure called a mantle plume. Tuzo Wilson, who postulated in 1963 that the formation of the Hawaiian Islands resulted from the slow movement of a tectonic plate across a hot region beneath the surface. The origins of the concept of hotspots lie in the work of J. Partial melting begins above the fusion point. Schematic diagram showing the physical processes inside the Earth that lead to the generation of magma. The alternative plate theory is that the mantle source beneath a hotspot is not anomalously hot, rather the crust above is unusually weak or thin, so that lithospheric extension permits the passive rising of melt from shallow depths. One suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core–mantle boundary. There are two hypotheses that attempt to explain their origins. A hotspot's position on the Earth's surface is independent of tectonic plate boundaries, and so hotspots may create a chain of volcanoes as the plates move above them. Examples include the Hawaii, Iceland, and Yellowstone hotspots. In geology, hotspots (or hot spots) are volcanic locales thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle. Lower diagram illustrates a hotspot track caused by the lithosphere's movement. Diagram showing a cross section through the Earth's lithosphere (in yellow) with magma rising from the mantle (in red).
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