Earth's Tectonic Plates

2. The oldest continental crust is about 4 ___ yrs old.
4. Causes the plates to move within Earth's mantle.
5. Plates move by _____ spreading.
7. Noticed that South America and Africa appeared to fit together like a puzzle.
8. ____ material is heather above the core.
10. A large chunk of lithosphere.
14. Some rocks contain little ____.
15. Plate move around Earth's surface at a rate of a few ____ a year.

1. Were once joined and the moved apart.
3. ___ is divided into plates.
6. A device capable of measuring the magnetic field.
9. ____ polar wonder is a phenomenon that the magnetic pole has seemed to moved.
10. The magnetic ___ reverses from time to time.
11. The point on Earth's surface directly above the place where an earthquake occurs.
12. Measures the ground shaking.
13. Rocks on the seafloor that were at the mid-ocean ridges.