Chapter 26, Problem 9RQ

To determine

The difference between the asthenosphere and the lithosphere.

Answer to Problem 9RQ

The asthenosphere is plastic and it is the region that consists of the outer core and lower zone of the upper mantle. The lithosphere is the region above the asthenosphere, which consists of the entire crust and top part of the mantle.

Explanation of Solution

The asthenosphere is the region that consists of the part of the outer core and lower zone of the upper mantle. It has is solid and has some amounts of liquid from partial melting of mantle rocks. The asthenosphere is plastic as it flows more easily than the lower mantle.

The lithosphere is above the asthenosphere. It is a 100 km thick layer and consists of whole crust and uppermost part of the mantle. It is more rigid, brittle and does not flow. Its appearance is like riding on the top of asthenosphere like a raft in a pond. The lithosphere is broken into pieces, which are called plates.

Conclusion:

Therefore, the asthenosphere is plastic and it is the region that consists of the outer core and lower zone of the upper mantle. The lithosphere is the region above the asthenosphere, which consists of the entire crust and top part of the mantle.