| A | B |
|---|
| Name the two types of the Earth's crust. | continental and oceanic |
| Continental crust is thicker/thinner than oceanic crust. | thicker (16-43 miles vs. 4-7 miles for oceanic) |
| Is oceanic crust denser than continental crust? | yes |
| No oceanic crust is more than ___ years old. | 200 million years |
| Some continental rocks are more than ____ years old. | 4 billion years old |
| The crust and the upper mantle form a strong structural unity called the ___ | lithosphere. |
| The lithosphere is made of the crust and the ___ | uppermost mantle. |
| The asthenosphere is a warm, deformable layer of the ___ | upper mantle just below the lithosphere. |
| The oceanic lithosphere has a top layer of ___ | oceanic crust, which ranges from 4-7 miles in thickness. |
| Oceanic crust is underlain by about 25 to 60 miles of ... | the uppermost mantle layer. |
