Search results
Results from the WOW.Com Content Network
Simplified model of mantle convection: [1] Whole-mantle convection. Mantle convection is the very slow creep of Earth's solid silicate mantle as convection currents carry heat from the interior to the planet's surface. [2] [3] Mantle convection causes tectonic plates to move around the Earth's surface. [4] The Earth's lithosphere rides atop the ...
Earth's mantle is a layer of silicate rock between the crust and the outer core. It has a mass of 4.01 × 10 24 kg (8.84 × 10 24 lb) and makes up 67% of the mass of Earth. [1] It has a thickness of 2,900 kilometers (1,800 mi) [1] making up about 46% of Earth's radius and 84% of Earth's volume.
Note: In chondrite model (1), the light element in the core is assumed to be Si. Chondrite model (2) is a model of chemical composition of the mantle corresponding to the model of core shown in chondrite model (1). [1] A photograph of Earth taken by the crew of Apollo 17 in 1972. A processed version became widely known as The Blue Marble. [2] [3]
Directly above the core–mantle boundary is a 200-kilometer (120 mi) thick layer of the lower mantle. This layer is known as the D″ ("D double-prime" or "D prime prime") or degree two structure. [6] LLSVPs were discovered in full mantle seismic tomographic models of shear velocity as slow features at the D″ layer beneath Africa and the ...
Earth's internal heat travels along geothermal gradients and powers most geological processes. [3] It drives mantle convection, plate tectonics, mountain building, rock metamorphism, and volcanism. [2] Convective heat transfer within the planet's high-temperature metallic core is also theorized to sustain a geodynamo which generates Earth's ...
Mantle convection occurs at rates of centimeters per year, and it takes on the order of hundreds of millions of years to complete a cycle of convection. Neutrino flux measurements from the Earth's core (see kamLAND ) show the source of about two-thirds of the heat in the inner core is the radioactive decay of 40 K , uranium and thorium.
The slab affects the convection and evolution of the Earth's mantle due to the insertion of the hydrous oceanic lithosphere. [3] Dense oceanic lithosphere retreats into the Earth's mantle, while lightweight continental lithospheric material produces active continental margins and volcanic arcs , generating volcanism . [ 4 ]
In practice, the RBL is defined by the depth at which the viscosity of the mantle rocks drops below ~.. [5] However, mantle material is a non-Newtonian fluid, i.e. its viscosity depends also on the rate of deformation. [6] This means that the LAB can change its position as a result of changes in the stresses.