| Includes | Crust and rigid part of the upper mantle |
|---|---|
| Classification | Mechanics |
| Is organized into | Tectonic plates |
Definition and context
The lithosphere comprises the crust and part of the upper mantle, which behave rigidly in the context of tectonics. It is divided into plates. This is a classification by mechanical behavior, different from the division by composition.
Saying that a plate is only crust leaves out part of the system. It also leads one to imagine that the mantle begins as a liquid immediately beneath it. The lithosphere-asthenosphere model needs to take conditions and time scales into account. To read a cross-section of the Earth, we can first ask what criterion it uses to draw its boundaries. That question makes it possible to correctly place names that appear together in diagrams but do not describe the same kind of division.
What we know and its limits
Introductory reference sheet. Properties and applications depend on measurement conditions; consult the sources before making comparisons.
Follow the evidence
The original sources for exploring this explanation and its limits.
- This Dynamic Earth · Inside the Earth
U.S. Geological Survey
Earth's crust, mantle, core, and mechanical structure. - Are the tectonic plates floating on magma?
U.S. Geological Survey
Why the asthenosphere is not a global ocean of magma.
Image credits
Photo by Alfo Medeiros on Pexels · Original source · Pexels License