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In fact, oceanic lithosphere is a thermal boundary layer for the convection [10] in the mantle. The thickness of the mantle part of the oceanic lithosphere can be approximated as a thermal boundary layer that thickens as the square root of time. [citation needed] Here, is the thickness of the oceanic mantle lithosphere, is the thermal ...
The age of the oceanic crust can be used to estimate the (thermal) thickness of the lithosphere, where young oceanic crust has not had enough time to cool the mantle beneath it, while older oceanic crust has thicker mantle lithosphere beneath it. [19] The oceanic lithosphere subducts at what are known as convergent boundaries. These boundaries ...
Oceanic: 5 – 10 km (3 – 6 mi) thick [4] and composed primarily of denser, more mafic rocks, such as basalt, diabase, and gabbro. The average thickness of the crust is about 15 – 20 km (9 – 12 mi). [5] Because both the continental and oceanic crust are less dense than the mantle below, both types of crust "float" on the mantle.
Lithosphere underlying ocean crust has a thickness of around 100 km (62 mi), whereas lithosphere underlying continental crust generally has a thickness of 150–200 km (93–124 mi). [5] The lithosphere and overlying crust make up tectonic plates, which move over the asthenosphere. Below the asthenosphere, the mantle is again relatively rigid.
Tectonic plates are pieces of Earth's crust and uppermost mantle, together referred to as the lithosphere. The plates are around 100 km (62 mi) thick and consist of two principal types of material: oceanic crust (also called sima from silicon and magnesium) and continental crust (sial from silicon and aluminium).
As a consequence, a powerful source generating plate motion is the excess density of the oceanic lithosphere sinking in subduction zones. When the new crust forms at mid-ocean ridges, this oceanic lithosphere is initially less dense than the underlying asthenosphere, but it becomes denser with age as it conductively cools and thickens.
T e is largely dependent on the thermal structure of the lithosphere, [4] its thickness and the coupling of crust with mantle. For the oceanic lithosphere with coupled crust and mantle, T e is usually taken to the base of the mechanical lithosphere (isotherm of 500 - 600 °C). This way it is also age dependent, as gradually thickens moving off ...
Oceanic lithosphere ranges in thickness from just a few km for young lithosphere created at mid-ocean ridges to around 100 km (62 mi) for the oldest oceanic lithosphere. [7] Continental lithosphere is up to 200 km (120 mi) thick. [ 8 ]