Search results
Results from the WOW.Com Content Network
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 ...
Convection within Earth's mantle is the driving force for plate tectonics. 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.
The silicate mantle of the Earth's moon is approximately 1300–1400 km thick, and is the source of mare basalts. [4] The lunar mantle might be exposed in the South Pole-Aitken basin or the Crisium basin. [4] The lunar mantle contains a seismic discontinuity at ~500 kilometers (310 miles) depth, most likely related to a change in composition. [4]
The internal structure of Earth. 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]
The following is a list of rock types recognized by geologists.There is no agreed number of specific types of rock. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe a rock type.
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
Geodynamics is a subfield of geophysics dealing with dynamics of the Earth.It applies physics, chemistry and mathematics to the understanding of how mantle convection leads to plate tectonics and geologic phenomena such as seafloor spreading, mountain building, volcanoes, earthquakes, faulting.
The remaining heat flow at the surface would be due to basal heating of the crust from mantle convection. Heat fluxes are negatively correlated with rock age, [1] with the highest heat fluxes from the youngest rock at mid-ocean ridge spreading centers (zones of mantle upwelling), as observed in the global map of Earth heat flow. [1]