Mantle plume

A mantle plume is theoretical upwelling of magma that occurs away from the boundaries of a continental plate.

Related Topics:
Magma - Continental plate

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Most volcanic and geothermal hotspots occur at the boundaries of two continental plates when one plate subducts under the other causing the mantle to melt. Volcanic and geothermal areas that occur away from the boundaries of plates cannot be explained by this process.

Related Topics:
Volcanic - Geothermal hotspots - Mantle

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In 1971, geophysicist, W. Jason Morgan proposed the theory of mantle plumes. In this theory, convection in the mantle slowly transports heat from the core to the Earth's surface. As magma in the lower mantle warms, it expands, becomes less dense and flows more readily. Plumes of hotter-than-average material rise through the mantle till it reaches the Earth's crust where is becomes a hotspot. The plumes originate at a thermal boundary layer. The only such layer known to exist in the deep mantle is the core-mantle boundary (D"), and thus Morgan-type plumes are generally assumed to rise from this layer. Due to the depth of such plumes, proving their existence is difficult and has led to some controversy over the theory.

Related Topics:
1971 - W. Jason Morgan - Convection - Boundary layer - Core

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