Two characteristics of Earth's crust are:
- Thickness and composition: Earth's crust varies in thickness from about 5 to 12 kilometers under the oceans (oceanic crust) to about 30 to 50 kilometers thick beneath the continents (continental crust). The continental crust is older, thicker, and less dense, composed mostly of felsic rocks like granite. The oceanic crust is younger, thinner, and denser, composed mainly of mafic rocks such as basalt and gabbro.
- Temperature increases with depth: The temperature within the Earth's crust rises as depth increases, at a rate of about 30 degrees Celsius for every kilometer below the surface. At the deepest regions of the crust, temperatures can range between about 200 to 400 degrees Celsius (400 to 750 degrees Fahrenheit).
These characteristics highlight the structural and thermal properties of Earth's outermost layer.