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Chapter 7
Lessons 1,2,&3
Term | Definition |
---|---|
Pangaea | ancient super continent, composed of land that forms today’s continents |
continental drift | hypothesis that continents are in constant motion |
magnetic reversal | event in which the magnetic field reverses direction |
mid-ocean ridge | mountain range located on the seafloor in the middle of the ocean |
normal polarity | today’s magnetic field; magnets orient themselves to point north |
reversed polarity | magnetic field in which magnets orient themselves to point south |
seafloor spreading | new oceanic crust forms at a mid-ocean ridge as old oceanic crust moves away |
plate tectonics | theory that Earth’s surface is made of rock plates that move with respect to each other |
lithosphere | cold rigid outermost rock layer of earth |
divergent plate boundary | where two tectonic plates separate |
transform plate boundary | where two plates slide by each other |
convergent plate boundary | where two plates collide |
subduction | sinking of a denser plate below a more buoyant plate at a convergent plate boundary |
convection | circulation of material caused by differences in temperature and density |
ridge push | force created by rising mantle of ocean ridges that creates potential for plates to move away from the ridge |
slab pull | force created by sinking of a plate, or slab, that pulls on the rest of the plate |