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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.
There is an ongoing discussion about whether the hotspot is caused by a deep mantle plume or originates at a much shallower depth. [3] Recently, seismic tomography studies have found seismic wave speed anomalies under Iceland, consistent with a hot conduit 100 km (62 mi) across that extends to the lower mantle.
A hotspot's position on the Earth's surface is independent of tectonic plate boundaries, and so hotspots may create a chain of volcanoes as the plates move above them. There are two hypotheses that attempt to explain their origins. One suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core–mantle boundary. [2]
The HawaiĘ»i hotspot is a volcanic hotspot located near the namesake Hawaiian Islands, in the northern Pacific Ocean.One of the best known and intensively studied hotspots in the world, [1] [2] the Hawaii plume is responsible for the creation of the Hawaiian–Emperor seamount chain, a 6,200-kilometer (3,900 mi) mostly undersea volcanic mountain range.
The conventional opinion is that volcanic activity associated with the hotspot results from movement of the North American Plate over a fixed mantle plume. During the first major episodes of volcanic activity, the plume created the igneous intrusions of the Monteregian Hills in southern Quebec and the younger set of intrusions of the White ...
This implies that the Iceland hotspot may be much older than the earliest rifting of what is now the northernmost Northeast Atlantic. If this is true, then much of the rifting in the North Atlantic was likely caused by thinning and bulging of the crust as opposed to the more direct influence of the mantle plume which sustains the Iceland ...
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]
The Canary hotspot, also called the Canarian hotspot, is a hotspot and volcanically active region centred on the Canary Islands located off the north-western coast of Africa. Hypotheses for this volcanic activity include a deep mantle plume beginning about 70 million years ago.