Science ocean floor & currents 7th grade

4. a depression of Earth's surface in which an ocean lies
6. huge pieces of lithosphere that slowly move on the asthenosphere and consist of the crust and the rigid, uppermost part of the mantle
8. melted or molten rock material beneath Earth's surface; cools slowly to form rocks with larger crystals
10. the process of forming something by forcing or pushing it out
11. a deep and narrow depression in the seafloor where the subducted plate moves into the asthenosphere
13. a mountain range that is found on the ocean floor
15. when two tectonic plates move away from each other

1. a dense, destructive mass of very hot ash, lava fragments, and gases ejected explosively from a volcano and typically flowing downslope at great speed
2. when two tectonic plates move towards each other, sometimes forming mountains
3. the formation of new areas of oceanic crust, which occurs through the upwelling of magma at midocean ridges and its subsequent outward movement on either side
5. the thin, solid, outermost layer of Earth; made of less dense silicates and is either continental (landmasses) or oceanic (ocean floors)
7. it causes a fault between two plates of the lithosphere, which will slide past one another
9. the process in which a denser plate is pushed downward beneath a less dense plate when plates converge; occurs at continental to oceanic boundaries and oceanic to oceanic boundaries
12. a hot liquid that comes from the mantle
14. an underwater mountain system formed by plate tectonics; the largest single volcanic feature on Earth