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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.
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 ...
One suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core–mantle boundary. [2] 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 ...
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]
Hot mantle materials rising up in a plume can spread out radially beneath the tectonic plate causing regions of uplift. [13] These ascending plumes play an important role in LIP formation. When created, LIPs often have an areal extent of a few million square kilometers and volumes on the order of 1 million cubic kilometers.
This model is strongly based on the results of global seismic tomography models, which typically show slab and plume-like anomalies crossing the mantle transition zone. Although it is accepted that subducting slabs cross the mantle transition zone and descend into the lower mantle, debate about the existence and continuity of plumes persists ...
Second, flow of hot mantle material encounters the base of the thin lithosphere and often results in melting and a new phase of volcanism. Delamination may thus account for some volcanic regions that have been attributed to mantle plumes in the past.
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]