Across
- 5. how many years ago did continental drift start?
- 7. subduction occurs at ______ plate boundries
- 9. how many big tectonic plates are there?
- 10. how many different plate boundaries are there?
- 11. ______ rock is found closest to the mid- ocean trenches
- 12. what type of plate boundary is the San Andres Fault?
- 15. what current determines the speed and direction a plate moves?
Down
- 1. who was the first person to have made a complete theory of continental drift
- 2. all lands
- 3. what boundaries cause Volcanos,Mountains,Trenches,and earthquakes
- 4. what boundary causes earthquakes,Volcanos, mid-ocean trenches, and rift valleys
- 6. what boundary causes earthquakes
- 8. ______ rocks are found farthest from the mid- ocean ridge
- 13. the upper layer of the Earth's mantel below the lithosphere
- 14. the rigid outer part of the earth consisting of the upper mantel and the Earth's crust