* Continental Crust: This is the crust that makes up the continents. It is thicker than oceanic crust, ranging from 30 to 70 kilometers (19 to 43 miles) thick. It is also less dense and composed primarily of granite and other less dense, felsic rocks.

* Oceanic Crust: This is the crust that makes up the ocean floor. It is thinner than continental crust, typically only about 5 to 10 kilometers (3 to 6 miles) thick. It is denser than continental crust and composed mostly of basalt and gabbro, which are denser, mafic rocks.