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Science Vocab Ch. 6
Plate Tectonics; Lessons 1 - 3
| Term | Definition |
|---|---|
| Pangaea | He proposed that all the continents were once part of a supercontinent called ... |
| Continental Drift | Wegener proposed the hypothesis of ..., which suggested that continents are in constant motion on the surface of Earth. |
| Mid-Ocean Ridge | The mountain ranges in the middle of the oceans are called ... |
| Seafloor Spreading | ... is the process by which new oceanic crust forms along a mid-ocean ridge and older oceanic crust moves away from the ridge. |
| Normal Polarity | Today's magnetic field, shown in Figure 8, is described as having ...-a state in which magnetized objects, such as compass needles, will orient themselves to point north. |
| Magnetic Reversal | Sometimes a ... occurs and the magnetic field reverses direction. |
| Reversed Polarity | The opposite of normal polarity is ...-a state in which magnetized objects would reverse direction and orient themselves to point south, as shown in Figure 8. |
| Plate Tectonics | The theory of ... states that Earth's surface is made of rigid slabs of rock, or plates, that move with respect to each other. |
| Lithosphere | The cold and rigid outermost rock layer is called the ... |
| Divergent Plate Boundary | A ... forms where two plates separate. |
| Transform Plate Boundary | A ... forms where two plates slide past each other. |
| Convergent Plate Boundary | ... form where two plates collide. |
| Subduction | The denser plate sinks below the more buoyant plate in a process called ... |
| Convection | You are probably already familiar with the process of ..., the circulation of material caused by differences in temperature and density. |
| Ridge Push | Rising mantle material at mid-ocean ridges creates the potential for plates to move away from the ridge with a force called ... |
| Slab Pull | As a slab sinks, it pulls on the rest of the plate with a force called ... |