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However, paleomagnetic data show that mantle plumes can also be associated with Large Low Shear Velocity Provinces (LLSVPs) [7] [8] and do move relative to each other. [9] The current mantle plume theory is that material and energy from Earth's interior are exchanged with the surface crust in two distinct and largely independent convective flows:
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]
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.
The resulting motion forms small clusters of small plumes right above the core-mantle boundary that combine to form larger plumes and then contribute to superplumes. The Pacific and African LLSVP, in this scenario, are originally created by a discharge of heat from the core (4000 K) to the much colder mantle (2000 K); the recycled lithosphere ...
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]
This is 0.087 watt/square metre on average (0.03 percent of solar power absorbed by Earth [23]), but is much more concentrated in areas where the lithosphere is thin, such as along mid-ocean ridges (where new oceanic lithosphere is created) and near mantle plumes. [24] Earth's crust effectively acts as a thick insulating blanket which must be ...
These are driven by magma intrusion and are associated with temperatures around 200–300 °C (392–572 °F) at more than 2 km (1.2 mi) depth while beyond the rift zones, particularly on the North American plate are found low-temperature geothermal fields related to local disturbances in the general heat flow from the mantle which have ...
The type of lava erupted was a mix of plume material and depleted upper mantle, similar to the type of lava found in the central Galapagos islands at the current time. From 14.5 million years to 12.5 million years ago: the Galapagos spreading centre moved south and the ridge overlay the southern edge of the hotspot.