What is Mantle Convection?

Information about Mantle Convection

Mantle convection is the slow creeping motion of Earth's rocky mantle in response to perpetual gravitationally unstable variations in its density. Material near the surface of Earth, particularly oceanic lithosphere, cools down by conduction of heat into the oceans and atmosphere, then thermally contracts to become dense, and then sinks under its own weight at convergent plate boundaries. This subducted material sinks to some depth in the Earth's interior where it is prohibited, by inherent density stratification, from sinking further. This stoppage creates a thermal boundary layer where sunken material soaks up heat via thermal conduction from below, and may become buoyant again to form upwelling mantle plumes.

Generally scientists who study mantle convection conduct their research at institutions or universities with well developed geology and/or oceanography departments.

Styles of convection

There is a current debate within the geophysics community as to whether convection is likely to be 'layered' or 'whole'. Geochemical studies of mid ocean ridge basalts (MORB) and tectonically emplaced upper mantle material have found it to be depleted in 'incompatible' elements such as U and Th; whereas material thought to be derived from the lower mantle i.e. ocean island basalts (OIB) is found to be enriched in incompatible elements. This suggests that the upper and lower mantle are not well mixed so that convection cells are layered with the boundary being between the upper and lower mantle at about 670 km depth. However, geophysicists have employed seismic tomography and have detected features reminiscent of slabs at subduction zones penetrating through the 670 km and down to at least 1800 km depth, this supports the whole mantle convection hypothesis.

US institutions (partial list)

See also

mantle is a ~2,900 km thick rocky shell comprising approximately 70% of Earth's volume. It is predominantly solid and overlies the Earth's iron-rich core, which occupies about 30% of Earth's volume.
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lithosphere (IPA: [ˈlɪθ.ə.sfiɹ], from the Greek for "rocky" sphere) is the solid outermost shell of a rocky planet. On the Earth, the lithosphere includes the crust and the uppermost mantle which is joined to the crust across the Mohorovičić
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Heat conduction or thermal conduction is the spontaneous transfer of thermal energy through matter, from a region of higher temperature to a region of lower temperature, and hence acts to even out temperature differences.
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Plate tectonics (from Greek τέκτων, tektōn "builder" or "mason") is a theory of geology that has been developed to explain the observed evidence for large scale motions of the Earth's lithosphere.
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mantle plume is an upwelling of abnormally hot rock within the Earth's mantle. As the heads of mantle plumes can partly melt when they reach shallow depths, they are thought to be the cause of volcanic centers known as hotspots and probably also to have caused flood basalts.
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mantle is a ~2,900 km thick rocky shell comprising approximately 70% of Earth's volume. It is predominantly solid and overlies the Earth's iron-rich core, which occupies about 30% of Earth's volume.
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Geodynamics is a subfield of geophysics dealing with dynamics of the Earth masses. Experts in geodynamics commonly use techniques such as geodetic GPS, InSAR, and seismology, to study the evolution of the Earth's Lithosphere, Mantle and Core.
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Plate tectonics (from Greek τέκτων, tektōn "builder" or "mason") is a theory of geology that has been developed to explain the observed evidence for large scale motions of the Earth's lithosphere.
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