Unit 2

4. a crack or a fracture in earth's lithosphere along which movement occurs
7. a vent in Earth's crust through which molten rock flows
9. a deep, underwater trough created by one plate subducting under another plate at a convergent plate boundary
10. the boundary between two plates that move away from eachother
11. a large mass of ice, formed by snow accumulation on land, that moves slowly across earth's surface
14. magma that erupts onto earth's surface
15. a naturally occurring solid composed of minerals, rock fragments, and sometimes other materials such as organic matter
16. the process that occurs when one tectonic plate moves under another tectonic plate
17. long narrow mountain range on the ocean floor; formed by magma at divergent plate boundaries

1. a violent, whirling column of air in contact with the ground
2. the mechanical and chemical processes that change Earth's surface over time
3. the boundary between two plates that slide past each other
5. the process by which new oceanic crust forms along a mid-ocean ridge and older oceanic crust moves away from the ridge
6. 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
8. the boundary between two plates that move toward each other
12. the laying down or settling of eroded material
13. vibrations caused by the rupture and sudden movement of rocks along a break or a crack in earth's crust