click below
click below
Normal Size Small Size show me how
Plate Tectonics Ch 4
Life on earth
| Question | Answer |
|---|---|
| Asthenosphere | Plasticlike layer of Earth on which the lithospheric plates float and move around. |
| Continental drift | Wegener's hypothesis that all continents were once connected in a single large landmass that broke apart about 200 million years ago and drifted slowly to their current positions. |
| Convection current | Current in Earth's mantle that transfers heat in Earth's interior and is the driving force for plate tectonics. |
| Lithosphere | Rigid layer of Earth about 100 km thick, made of the crust and a part of the upper mantle. |
| Pangaea | Large, ancient landmass that was composed of all the continents joined together. |
| Plate | A large section of Earth's oceanic or continental crust and rigid upper mantle that moves around on the asthenosphere. |
| Plate tectonics | Theory that Earth's crust and upper mantle are broken into plates that float and move around on a plasticlike layer of the mantle. |
| Seafloor spreading | Hess's theory that new seafloor is formed when magma is forced upward toward the surface at a mid-ocean ridge. |