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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.
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 ...
That mantle plumes are much more complex than originally hypothesised and move independently of each other and plates is now used to explain such observations. [ 8 ] In 2020, Wei et al. used seismic tomography to detect the oceanic plateau, formed about 100 million years ago by the hypothesized mantle plume head of the Hawaii-Emperor seamount ...
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]
Magnetotelluric imaging has found higher conductivity in the upper mantle under the active area southeast of Tahiti consistent with anomalously hot rising material. [9] [10] There are two competing versions of the mantle plume model. One version posits a narrow, discreet plume feeding only the Society hotspot.
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]
Volcanic plume or volcanic plume may refer to: Eruption plume , a column of hot volcanic ash and gas emitted into the atmosphere during an explosive volcanic eruption Mantle plume , an upwelling of abnormally hot rock within the Earth's mantle, which can cause volcanic hotspots