What Best Describes the Relationship Between Earth's Crust & the Lithosphere? | Sciencing
What is the difference between the crust and lithosphere? oceanic) is the thin layer of distinctive chemical composition overlying the ultramafic upper mantle. You see some of the rocky crust, but that's only 1 percent of the Earth's mass. Beneath the crust is the dense, semisolid mantle, which accounts. The division in the lithosphere between the crust and the mantle is the difference in ductility between the two layers of the upper mantle.
Earth's Mantle Earth's mantle is thought to be composed mainly of olivine-rich rock. It has different temperatures at different depths.Layers of the Earth - Hindi
The temperature is lowest immediately beneath the crust and increases with depth. The highest temperatures occur where the mantle material is in contact with the heat-producing core.
This steady increase of temperature with depth is known as the geothermal gradient. The geothermal gradient is responsible for different rock behaviors, and the different rock behaviors are used to divide the mantle into two different zones. Rocks in the upper mantle are cool and brittle, while rocks in the lower mantle are hot and soft but not molten.
Earth's Internal Structure - Crust Mantle Core
Rocks in the upper mantle are brittle enough to break under stress and produce earthquakes. This solid portion of the Earth has been identified because it continually moves in slow motion.
Rearranging Rocks The lithosphere is the brittle solid-rock section of the planet, averaging about kilometers 62 miles deep. It is thinner under the oceans and thicker in mountain areas. The oceanic lithosphere is denser than that of the continents.
The rock of the lithosphere is divided into many uneven pieces called tectonic plates. Some, like those under the Pacific Ocean and Antarctica, are enormous; they are thousands of kilometers wide. Others extend just a few hundred kilometers. Extreme heat of the mantle makes the rock more flexible, so it moves more easily.
At subduction zones this mafic crust was prone to metamorphose into greenschist instead of blueschist at ordinary blueschist facies.
As plates diverge at these ridges, magma rises into the upper mantle and crust. As it moves away from the ridge, the lithosphere becomes cooler and denser, and sediment gradually builds on top of it.
Earth's Internal Structure
The youngest oceanic lithosphere is at the oceanic ridges, and it gets progressively older away from the ridges. The amount of melt produced depends only on the temperature of the mantle as it rises.
An example of this is the Gakkel Ridge under the Arctic Ocean. Thicker than average crust is found above plumes as the mantle is hotter and hence it crosses the solidus and melts at a greater depth, creating more melt and a thicker crust.
These boundaries can exist between oceanic lithosphere on one plate and oceanic lithosphere on another, or between oceanic lithosphere on one plate and continental lithosphere on another.