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Identified mantle components are DMM (depleted mid-ocean ridge basalt (MORB) mantle), HIMU (high U/Pb-ratio mantle), EM1 (enriched mantle 1), EM2 (enriched mantle 2) and FOZO (focus zone). [ 22 ] [ 23 ] This geochemical signature arises from the mixing of near-surface materials such as subducted slabs and continental sediments, in the mantle ...
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]
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]
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 ...
The weak visibility of the postulated plume in tomographic images of the lower mantle and the geochemical evidence for eclogite in the mantle source have led to the theory that Iceland is not underlain by a mantle plume at all, but that the volcanism there results from processes related to plate tectonics and is restricted to the upper mantle ...
Some observations, such as a lack of age-progressive volcanism and the geochemical signatures of lavas which indicate a shallow source materials, are inconsistent with the plume model, and some scientists have argued that the Cape Verde Archipelago is a product rather of sub-lithospheric small-scale convection and instabilities arising from ...
The formation and development of plumes in the early mantle contributed to triggering the lateral movement of crust across the Earth's surface. [18] The effect of upwelling mantle plumes on the lithosphere can be seen today through local depressions around hotspots such as Hawaii. The scale of this impact is much less than that exhibited in the ...
CLIP formed as a large igneous province and now forms a thickened zone of oceanic crust between the North American and South American plates. [2] In some places the oceanic crust is 2–3 times as thick as normal oceanic crust (15–20 km (9.3–12.4 mi) vs 7 km (4.3 mi).