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The lower mantle, historically also known as the mesosphere, represents approximately 56% of Earth's total volume, and is the region from 660 to 2900 km below Earth's surface; between the transition zone and the outer core. [1] The preliminary reference Earth model (PREM) separates the lower mantle into three sections, the uppermost (660–770 ...
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] 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.
Mantle convection. 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]
Plates in the crust of Earth. Earth's crust is its thick outer shell of rock, referring to less than one percent of the planet's radius and volume. It is the top component of the lithosphere, a solidified division of Earth 's layers that includes the crust and the upper part of the mantle. [1] The lithosphere is broken into tectonic plates ...
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
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 Earth's mantle is a layer of silicate rock between the crust and the outer core. Its mass of 4.01 × 10 24 kg is 67% the mass of the Earth. [1] It has a thickness of 2,900 kilometres (1,800 mi) [1] making up about 84% of Earth's volume. It is predominantly solid, but in geological time it behaves as a viscous fluid.
The asthenosphere is a part of the upper mantle just below the lithosphere that is involved in plate tectonic movement and isostatic adjustments. It is composed of peridotite, a rock containing mostly the minerals olivine and pyroxene. [ 2 ] The lithosphere-asthenosphere boundary is conventionally taken at the 1,300 °C (2,370 °F) isotherm.