Search results
Results From The WOW.Com Content Network
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.
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]
In this model, cold subducting oceanic lithosphere descends all the way from the surface to the core–mantle boundary (CMB), and hot plumes rise from the CMB all the way to the surface. [14] This model is strongly based on the results of global seismic tomography models, which typically show slab and plume-like anomalies crossing the mantle ...
Scientists discovered "deep mantle waves" causing interiors of continents to rise. Now we understand mantle processes and impacts on biodiversity and climate. The Continents Are Secretly Rising ...
Because of the perceived fixity of some volcanic sources relative to the plates, he proposed that this thermal boundary was deeper than the convecting upper mantle on which the plates ride and located it at the core-mantle boundary, 3,000 km beneath the surface. He suggested that narrow convection currents rise from fixed points at this thermal ...
Mantle convection is the result of a thermal gradient: the lower mantle is hotter than the upper mantle, and is therefore less dense. This sets up two primary types of instabilities. In the first type, plumes rise from the lower mantle, and corresponding unstable regions of lithosphere drip back into the mantle.
The mantle plume hotspot that is half the cause of Iceland's intense volcanism (the other half being the Mid-Atlantic Ridge) is believed to have been the cause of the largest mass extinction event ...
Because of the temperature difference between the Earth's surface and outer core and the ability of the crystalline rocks at high pressure and temperature to undergo slow, creeping, viscous-like deformation over millions of years, there is a convective material circulation in the mantle. [8] Hot material rises (in a mantle plume) while cooler ...