Plate Tectonics Vocab

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Across
  1. 4. the study of changes in Earth's magnetic field, as shown by patterns of magnetism in rocks that have formed over time
  2. 6. the theory that proposes the Earth's outer shell consists of individual plates that interact in numerous ways. These plates can produce volcanoes, earthquakes, mountains, and the crust
  3. 8. the thin, rocky, outer layer of Earth
  4. 10. a chain of volcanic islands generally located a few hundred kilometers from a trench where subduction of one oceanic slab beneath another is occurring
  5. 12. a boundary by which two plates move together
  6. 14. one of the numerous rigid sections of the lithosphere that moves as a unit over the asthenosphere
  7. 16. a mechanism that contributes to plate motion in which cool, dense oceanic crust sinks into the mantle and pulls the lithosphere along
  8. 17. the motion of matter from changes in temperature
  9. 19. the solid innermost layer of Earth (1220 km in radius)
  10. 20. a boundary where two plates slide past each other without creating nor destroying the lithosphere
  11. 22. a proposed supercontinent that began to break about 200 million years ago and formed today's landmasses
  12. 23. a layer beneath the mantle (2260 km thick) containing liquid iron and generating Earth's magnetic field
  13. 24. a mechanism that may contribute to plate motion; it involves the oceanic lithosphere sliding down the oceanic ridge due to gravity
  14. 25. The rigid outer layer of Earth, including the crust and upper mantle
Down
  1. 1. the process by which oceanic crust sinks beneath a trench back to the mantle al a colliding plate boundary
  2. 2. mountains formed in part by volcanic activity caused by the subduction of oceanic lithosphere beneath a continent
  3. 3. The 2890 km thick layer of Earth below the crust
  4. 5. a region where the rigid plates are moving apart, typified by the oceanic ridges
  5. 7. a mass of hotter than normal mantle material that ascends toward the surface, where it can lead to igneous activity
  6. 9. deep faulted structure found along the axes of divergent plate boundaries (can develop on seafloor or land)
  7. 11. the process which plate tectonics produce new oceanic lithospheres at the ocean ridges
  8. 13. Ocean Trench / topographic depression of the sea floor
  9. 15. a hypothesis that states the continents were once a supercontinent but, are now moving
  10. 18. A sound navigation and ranging tool that calculates ocean depth by recording the time of an energy pulse
  11. 21. a weak plastic layer of the mantle below the lithosphere