Hotspot (geology)

A hotspot is a localized, long-lived region of unusually hot mantle that generates magma and can form volcanoes as a tectonic plate moves above it.

Mantle plume: A rising column of hot, buoyant solid material within a planet’s mantle. Plumes are a leading explanation for how some hotspots deliver excess heat beneath plates.
Hawaiian–Emperor seamount chain: A volcanic chain in the Pacific Ocean recording changes in the motion of the Pacific Plate. Its bend preserves evidence of a major change in plate-motion direction.
J. Tuzo Wilson: A Canadian geophysicist who helped establish plate tectonics and proposed fixed volcanic sources beneath moving plates. Wilson used Hawaiian volcanoes to propose a mechanism for age-progressive volcanic chains.
Mid-ocean ridge: A long underwater mountain chain where tectonic plates diverge and new oceanic crust forms. Ridge volcanism is driven by plate separation, unlike volcanism centered away from boundaries.
Hotspot drift: The movement of hotspot sources relative to one another or to a mantle reference frame. Measured drift complicates reconstructions that assume every hotspot remains stationary.
Decompression melting: Partial melting that occurs when hot rock rises and pressure falls without substantial cooling. Rising mantle can melt by decompression, supplying magma beneath a hotspot.
Hawaii hotspot: A volcanic source beneath the Pacific Plate responsible for the Hawaiian Islands and older seamounts. It is the classic example of volcanism attributed to a relatively fixed hotspot.
W. Jason Morgan: An American geophysicist who developed the mantle-plume hypothesis and its role in plate tectonics. Morgan formalized the idea that deep mantle plumes could produce hotspot tracks.
Subduction zone volcanism: Volcanism above a descending tectonic plate, commonly caused by water-assisted melting in the mantle wedge. It produces volcanic arcs through a distinct melting process rather than hotspot activity.
Deep mantle plume: A proposed rising column of hot mantle originating near the core–mantle boundary. Whether hotspots require deep-rooted plumes remains disputed.

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