What is the lithosphere?
The lithosphere is the solid outer layer of the Earth. This is the part that you, and I, and every other person on Earth stands on every day. But it’s not just us! This is the part of Earth that we build our schools, stores and homes upon!
Geologists examine the characteristics of the lithosphere and the processes that formed it. These processes are still continuing to shape it today.
The lithosphere is one of the five great characteristics that make Earth what it is! The others are: the biosphere (living things), the cryosphere (frozen regions), the hydrosphere (liquid water), and the atmosphere (air surrounding). These five characteristics work together to make Earth the great planet that it is!
What is the Relationship Between the Crust and the Lithosphere?
What is it made of?
The lithosphere is the most rigid, and rocky of Earth’s layers. The rocks that make up this layer are considered “elastic”, which means they are able to bend. Yet, they are not considered “viscous”, which is a thick and sticky liquid. But, the magma in the asthenosphere is viscous.
Interactions between the Lithosphere and the Mantle
There is a spot where the athenosphere and lithosphere come together. We call it the lithosphere-asthenosphere boundary. We will call it LAB for short. Geologists study the LAB to find the difference in ductility of the two layers. Ductility is a solid material’s ability to stretch under pressure. The asthenosphere is a lot more ductile than the lithosphere.
Both the elasticity and ductility of the lithosphere depend on the temperature, stress, and curve of the Earth. It’s separated into about a dozen rigid plates. We call these tectonic plates.
Scientists believe that what causes the movement of these plates is slow convection currents. You can find these far into the mantle. The convection currents are created by the interior being radioactively heated. They form columns of magma, called plumes.
Lithospheric Events and Plate Distribution
You’re probably wondering why the continents have not moved all around from this. Well, this is because the movement is so tiny, it almost can go unnoticed. The plates move at a rate of only several inches per year!
There are seven major tectonic plates that make up the lithosphere. But there are many other minor plates too.
Despite it being heated, the lithosphere is also the coolest layer of the Earth. Some scientists believe the radioactive heat has to do with the “plastic” mantle below it. It’s called plastic because it’s like the plastic we use every day. When it heats it can be shaped.
The lithosphere is really thick, sixty miles on average! If you were to drive through it, it would take you about an hour!
For more information, watch this video:
Other Great Resources:
Kids Fun Science: http://www.kids-fun-science.com/lithosphere.html
Easy Science for Kids: http://easyscienceforkids.com/all-about-lithosphere/