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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.
Permanent uplift can occur when igneous material is injected into the crust, and circular or elliptical structural uplift (that is, without folding) over a large radius (tens to thousands of km) is one characteristic of a mantle plume. [3] [4]
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.
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]
Uplift of the Sierra Nevada mountain range in California and the Colorado Plateau has occurred on the flanks as a result of the loss of high density lower lithosphere. Eclogite xenoliths found within the crust in the region support the metamorphic phase change associated with the density inversion in the lower crust. [ 3 ]
Based on the environmental correlations and current topographic locations of the Jurassic Upper Limestone and Cretaceous Upper Sandstone, the net rock uplift of the Ethiopian Plateau would be 2.2 km (1.4 mi) since c. 150 Mya. The thinned Ethiopian lithosphere could have resulted in ponding from mantle plume and subsequent uplift.
Epeirogenic uplift is a long-wavelength form of uplift and be split up into two separate categories, which is transient and permanent. Permanent epeirogenic uplift is possibly mainly produced by magmatic underplating, [10] while transient uplift is more involved with mantle convection. [9]
Hot mantle materials rising up in a plume can spread out radially beneath the tectonic plate causing regions of uplift. [13] These ascending plumes play an important role in LIP formation. When created, LIPs often have an areal extent of a few million square kilometers and volumes on the order of 1 million cubic kilometers.