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On Earth, the Rayleigh number for convection within Earth's mantle is estimated to be of order 10 7, which indicates vigorous convection. This value corresponds to whole mantle convection (i.e. convection extending from the Earth's surface to the border with the core). On a global scale, surface expression of this convection is the tectonic ...
Earth heat transport occurs by conduction, mantle convection, hydrothermal convection, and volcanic advection. [15] Earth's internal heat flow to the surface is thought to be 80% due to mantle convection, with the remaining heat mostly originating in the Earth's crust, [16] with about 1% due to volcanic activity, earthquakes, and mountain ...
The pressure at the bottom of the mantle is ≈140 GPa (1.4 Matm). [24] The mantle is composed of silicate rocks richer in iron and magnesium than the overlying crust. [25] Although solid, the mantle's extremely hot silicate material can flow over very long timescales. [26] Convection of the mantle propels the motion of the tectonic plates in the
David A. Bercovici (born in September 1960) is an American geophysicist. He is primarily known for his theoretical explanations of why planet Earth has plate tectonics.He is also known for his development of models of how the Earth's mantle recycles and stores water and how such hydrological processes are involved in Earth's geochemical history.
The volcanism often attributed to deep mantle plumes is alternatively explained by passive extension of the crust, permitting magma to leak to the surface: the plate hypothesis. [23] The convection of the Earth's mantle is a chaotic process (in the sense of fluid dynamics), which is
The catastrophe is defined as when the mean mantle temperature exceeds the mantle solidus so that the entire mantle melts. Using the geochemically preferred Urey ratio of U r = 1 / 3 {\displaystyle Ur=1/3} and the geodynamically preferred cooling exponent of beta = 1 / 3 {\displaystyle {\text{beta}}=1/3} the mantle temperature reaches the ...
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.
Geodynamic mantle convection models have included compositional distinctive material. The material tends to get swept up in ridges or piles. [ 10 ] When including realistic past plate motions into the modeling, the material gets swept up in locations that are remarkably similar to the present day location of the LLSVPs. [ 18 ]
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