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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 ...
Earth's inner core is the innermost geologic layer of the planet Earth. It is primarily a solid ball with a radius of about 1,220 km (760 mi), which is about 19% of Earth's radius [0.7% of volume] or 70% of the Moon 's radius. [32][33] The inner core was discovered in 1936 by Inge Lehmann and is generally composed primarily of iron and some nickel.
The core–mantle boundary (CMB) of Earth lies between the planet's silicate mantle and its liquid iron–nickel outer core, at a depth of 2,891 km (1,796 mi) below Earth's surface. The boundary is observed via the discontinuity in seismic wave velocities at that depth due to the differences between the acoustic impedances of the solid mantle ...
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.
Oxygen cycle refers to the movement of oxygen through the atmosphere (air), biosphere (plants and animals) and the lithosphere (the Earth’s crust). The oxygen cycle demonstrates how free oxygen is made available in each of these regions, as well as how it is used. The oxygen cycle is the biogeochemical cycle of oxygen atoms between different ...
Earth's crust and mantle, Moho discontinuity between bottom of crust and solid uppermost mantle. The Mohorovičić discontinuity (/ ˌ m oʊ h ə ˈ r oʊ v ɪ tʃ ɪ tʃ / MOH-hə-ROH-vih-chitch; Croatian: [moxorôʋiːtʃitɕ]) [1] – usually called the Moho discontinuity, Moho boundary, or just Moho – is the boundary between the crust and the mantle of Earth.
In ecology, stratification refers to the vertical layering of a habitat; the arrangement of vegetation in layers. [1][2] It classifies the layers (sing. stratum, pl. strata) of vegetation largely according to the different heights to which their plants grow. The individual layers are inhabited by different animal [3] and plant communities ...
Several hypotheses have been proposed for the origin and persistence of LLSVPs, depending on whether the provinces represent purely thermal unconformities (i.e. are isochemical in nature, of the same chemical composition as the surrounding mantle) or represent chemical unconformities as well (i.e. are thermochemical in nature, of different chemical composition from the surrounding mantle).