| A | B |
|---|
| continental drift | Wegeners idea that continents slowly moved over the earth |
| Pangaea | supercontinent |
| Wegeners hypothesis | that the continets were once together |
| fossil | any trace of an ancient organism in pressed rock |
| climate change | used by wegener to support hypothesis |
| Sonar | devie that uses sound waves to measure distance |
| sea-floor spreading | mid ocean ridges continually add new material to the ocean floor |
| deep ocean trenches | deep underwater canyans |
| subduction | process where ocean floor sinks beneath a trench |
| size and shape of oceans | can be changed by subduction |
| atlantic ocean | is expanding because of subduction |
| divergent boundary | plates move apart |
| convergent boundary | plates come together |
| transform boundary | plates slip past each other |
| plate techtonics | combined theory about plate motions |
| satellites | used to measure plate movement |
| Faults | where plate boundaries meet |
| rift valley | crust diverges on land |
| Andes mtns | example of a convergen boundary |
| San Andreas fault | example of a transform boundary |
| mid ocean ridge | chain of mtns in the ocean |
| a mountain | formers when plates converge |
