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A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. [2] Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hotspots, such as Hawaii or Iceland, and large igneous provinces such as the Deccan and Siberian Traps.
A schematic evolutionary diagram showing the impact of a mantle plume on the early lithosphere (dark blue) and surface proto-crust (brown). This initiated subduction and subsequent global plate tectonics within a previously unseparated lithosphere that had no lateral surface movement.Modified from [17]
If LLSVPs represent purely thermal unconformities, then they may have formed as large mantle plumes of hot, upwelling mantle. However, geodynamical studies predict that isochemical upwelling of a hotter, lower viscosity material should produce long, narrow plumes, [13] unlike the large, wide plumes seen in LLSVPs. It is important to remember ...
Mantle plumes were first proposed by J. Tuzo Wilson in 1963 [4] [non-primary source needed] and further developed by W. Jason Morgan in 1971. A mantle plume is posited to exist where hot rock nucleates [clarification needed] at the core-mantle boundary and rises through the Earth's mantle becoming a diapir in the Earth's crust. [5]
Simplified model of mantle convection: [1] Whole-mantle convection. Mantle convection is the very slow creep of Earth's solid silicate mantle as convection currents carry heat from the interior to the planet's surface. [2] [3] Mantle convection causes tectonic plates to move around the Earth's surface. [4]
A mantle plume rises from the core to the surface. P-T-t paths play an important role in the development of plume tectonics, supported by anticlockwise P-T paths. [11] [49] Plume tectonics are considered to be the dominant process forming the Archean crust with evidence from the study of the Archean cratonic blocks in the North China Craton.
It was later postulated that hotspots are fed by streams of hot mantle rising from the Earth's core–mantle boundary in a structure called a mantle plume. [6] Whether or not such mantle plumes exist has been the subject of a major controversy in Earth science, [4] [7] but seismic images consistent with evolving theory now exist. [8]
This is widely believed to have been supplied by a mantle plume impinging on the base of the Earth's lithosphere, its rigid outermost shell. [29] [30] [15] The plume consists of unusually hot mantle rock of the asthenosphere, the ductile layer just below the lithosphere, that creeps upwards from deeper in the Earth's interior. [31]