This drawing shows the Earth's lithosphere (crust and upper mantle) on top of the asthenosphere.
Click on image for full size
The Earth's Crust, Lithosphere and Asthenosphere
Crust, the upper layer of the Earth, is not always the same. Crust under the oceans is only about 5 km thick while continental crust can be up to 65 km thick. Also, ocean crust is made of denser minerals than continental crust.
The tectonic plates are made up of Earth’s crust and the upper part of the mantle layer underneath. Together the crust and upper mantle are called the lithosphere and they extend about 80 km deep. The lithosphere is broken into giant plates that fit around the globe like puzzle pieces. These puzzle pieces move a little bit each year as they slide on top of a somewhat fluid part of the mantle called the asthenosphere. All this moving rock can cause earthquakes.
The asthenosphere is ductile and can be pushed and deformed like silly putty in response to the warmth of the Earth. These rocks actually flow, moving in response to the stresses placed upon them by the churning motions of the deep interior of the Earth. The flowing asthenosphere carries the lithosphere of the Earth, including the continents, on its back.
Shop Windows to the Universe Science Store!
You might also be interested in:
The main force that shapes our planet’s surface over long amounts of time is the movement of Earth's outer layer by the process of plate tectonics. This picture shows how the rigid outer layer of the...more
The expression “on solid ground” is often used to describe something as stable. Usually the solid ground underfoot seems very stable. But sometimes it is not. "The ground seemed to twist under us like...more
Meanwhile the seeds of continents called the "continental shields" began to take shape. The material which makes the continents is lighter and more bouyant than other crustal material, somewhat like the...more
Plates at our planet’s surface move because of the intense heat in the Earth’s core that causes molten rock in the mantle layer to move. It moves in a pattern called a convection cell that forms when...more
Many kinds of surface features are clues that our lithosphere is sliding. Two types of features can form when plates move apart. At mid ocean ridges, the bottom of the sea splits apart and new crust is...more
As the Earth cools, hot material from the deep interior rises to the surface. Hot material is depicted in red in this drawing, under an ocean shown in blue green. The hotter material elevates the nearby...more
Like the Earth's lithosphere, the Martian lithosphere is the not-so-rigid part of the crust of Mars which is cooler than the interior of Mars somewhat like the film on top of a cup of hot cocoa. On Earth,...more