Summary:
- Crust, mantle, and core differ from each other in chemical composition.
- Earth’s crust is a thin, brittle outer shell.
- The crust is made of rock.
- This layer is thinner under the oceans and much thicker in mountain ranges.
- There are two kinds of crust.
- Oceanic crust is thinner and denser than continental crust.
- Continental crust is much thicker than oceanic crust.
- It is 35 kilometers (22 miles) thick on average.
- All three major rock types—igneous, metamorphic, and sedimentary—are found in the crust.