| Question |
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| Answer |
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| divergent |
boundary where 2 plates are moving away from each other; associated with mid-ocean ridges |
| convergent |
boundary where 2 plates are colliding; associated with deep-sea trenches, volcanoes, and mountains |
| transform |
boundary where 2 plates are sliding past one another; associated with faults and earthquakes |
| Wegener |
man who came up with the theory of continental drift |
| Hess |
man given credit for the theory of plate tectonics |
| basalt |
rock that covers most of the ocean floor |
| Pangaea |
name of the supercontinent 200 million years ago |
| continental drift |
theory stating the continents used to be joined in a single land mass and have since drifted to their current locations |
| subduction |
one tectonic plate is being forced under another tectonic plate |
| mid-ocean ridge |
chain of underwater mountains |
| deep-sea trench |
long, narrow depression on the ocean floor; occurs at convergent boundaries |
| plate tectonics |
theory that the Earth's crust is broken into plates which move in different directions at different speeds |
| lithosphere |
strong, rigid layer of Earth including the uppermost mantle and overlying crust |
| asthenosphere |
a weak plastic-like layer of the mantle situated below the lithosphere; convection currents happen here |
| seafllor spreading |
theory stating that new crust is made at mid-ocean ridges and old crust is destroyed at deep-sea trenches |
| rift valley |
long narrow depression that forms when continental crust separates at a divergent boundary |
| fault |
fracture in the Earth's crust; transform boundary |
500 Words
