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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.
The Iceland plume is a postulated upwelling of anomalously hot rock in the Earth's mantle beneath Iceland.Its origin is thought to lie deep in the mantle, perhaps at the boundary between the core and the mantle at about 2,880 km (1,790 mi) depth.
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]
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]
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 ...
The volcanism often attributed to deep mantle plumes is alternatively explained by passive extension of the crust, permitting magma to leak to the surface: the plate hypothesis. [24] The convection of the Earth's mantle is a chaotic process (in the sense of fluid dynamics), which is
Evidence for a plume origin includes the above age progression, seismic anomalies in the lower mantle under the Great Meteor Seamount (though these do not extend into the upper mantle as expected for a plume), [5] [6] and helium isotope ratios in groundwater in the Monteregian Hills which indicate a deep mantle source. [7]
The deep mantle plume hypothesis on Canary hotspot formation proposes how the current-day Canary islands rested above a province of tholeiitic magma during the Triassic Period. The province, known as the Central Atlantic Magmatic Province (CAMP), became active and extended over 10 million km 2 , developing into what scientists call today the ...