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Chapter 7 Vocabulary
Term | Definition |
---|---|
Pangaea | when all the continents were one subcontinent |
continental drift | suggestion that continents are in constant motion on the surface of Earth |
mid-ocean ridge | the mountain ranges in the middle of the oceans |
seafloor spreading | the process by which new oceanic crust forms along a mid-ocean ridge and older oceanic crust moves away from the ridge |
normal polarity | a state in which magnetized objects, such as compass needles, will orient themselves to point north |
magnetic reversal | occurs and causes the magnetic field to reverse direction |
reversed polarity | a state in which magnetized objects would reverse direction and orient themselves to point south |
plate tectonics | theory that states that Earth's surface is made up of rigid slabs of rock, or plates, that move with respect to each other |
lithosphere | the cold and rigid outermost rock layer |
divergent plate boundary | forms where two plates separate |
transform plate boundary | forms where two plates slide past each other |
convergent plate boundary | forms where two plates collide |
subduction | a process where the denser plate sinks below the more buoyant plate |
convection | the circulation of material caused by differences in temperature and density |
ridge push | when rising mantle material at mid-ocean ridges creates the potential for plates to move from the ridge |
slab pull | when a slab sinks, it pulls on the rest of the plate |