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The highest pressure of the upper mantle is 24.0 GPa (237,000 atm) [13] compared to the bottom of the mantle, which is 136 GPa (1,340,000 atm). [12] [16] Estimates for the viscosity of the upper mantle range between 10 19 and 10 24 Pa·s, depending on depth, [17] temperature, composition, state of stress, and numerous other factors. The upper ...
Estimates for the viscosity of the upper mantle range between 10 19 and 10 24 Pa·s, depending on depth, [25] temperature, composition, state of stress, and numerous other factors. Thus, the upper mantle can only flow very slowly.
The transition zone is the part of Earth's mantle that is located between the lower and the upper mantle, most strictly between the seismic-discontinuity depths of about 410 to 660 kilometres (250 to 410 mi), but more broadly defined as the zone encompassing those discontinuities, i.e., between about 300 and 850 kilometres (190 and 530 mi) depth. [1]
If you want to understand the geology of our home planet, studying the mantle is a great place to start. Separating the planet’s rocky crust and the molten outer core, the mantle makes up 70 ...
The asthenosphere (from Ancient Greek ἀσθενός (asthenós) 'without strength') is the mechanically weak [1] and ductile region of the upper mantle of Earth. It lies below the lithosphere, at a depth between c. 80 and 200 km (50 and 120 mi) below the surface, and extends as deep as 700 km (430 mi). However, the lower boundary of the ...
Scientists using an ocean drilling vessel have dug the deepest hole ever in rock from Earth's mantle - penetrating 4,160 feet (1,268 meters) below the Atlantic seabed - and obtained a large sample ...
The thickness of the lithosphere is thus considered to be the depth to the isotherm associated with the transition between brittle and viscous behavior. [2] The temperature at which olivine becomes ductile (~1,000 °C or 1,830 °F) is often used to set this isotherm because olivine is generally the weakest mineral in the upper mantle. [3]
The depth to the base of the CBL can be determined from the amount of forsterite within samples of olivine extracted from the mantle. This is because partial melting of primitive or asthenospheric mantle leaves behind a composition that is enriched in magnesium, with the depth at which the concentration of magnesium matches that of the ...