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Chapter 3 Vocab
| Term | Definition |
|---|---|
| Continental Drift | The hypothesis that the continents slowly move across Earth's surface. |
| Pangaea | The name of the single landmass that began to break apart 200 million years ago and gave rise to today's continents. |
| Fossil | The preserved remains or traces of an organism that lived in the past. |
| Mid-ocean Ridge | An undersea mountain chain where new ocean floor is produced; a divergent plate boundary. |
| Sea-flooring spreading | The process by which molten material adds new oceanic crust to the ocean floor. |
| Deep-ocean Trench | A deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle. |
| Subduction | The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at the convergent boundary. |
| Plate | A section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust. |
| Divergent Boundary | A plate boundary where two plates move away from each other. |
| Convergent Boundary | A plate boundary where two plates move toward each other. |
| Transform Boundary | A plate boundary where two plates move past each other in opposite directions. |
| Plate Tectonics | The theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle. |
| Fault | A break in Earth's crust along which rocks move. |
| Rift Valley | A deep valley that forms where two plates move apart. |