Plate Tectonics
Across
- 4. places where plates slide sideways past each other.
- 5. rupture in the crust that allows hot lava volcanic ash and gases to escape from a magma chamber below the surface
- 6. the rigid outer part of the earth consisting of the crust and upper mantle.
- 7. a region of the Earth's crust where tectonic plates meet and one plate moves underneath the other
- 12. the upper layer of the earth's mantle below the lithosphere in which there is relatively low resistance to plastic flow and convection is thought to occur.
- 13. a supercontinent that assembled approximately 335 million years ago
- 16. occurs when two tectonic plates move away from each other
- 18. the movement of fluid that results from convection.
- 19. the outermost layer of rock of which a planet consists especially the part of the earth above the mantle.
- 20. an extended break in a body of rock marked by the relative displacement and discontinuity of strata on either side of a particular surface.
Down
- 1. located at the juncture of crustal plates that form the floor of the Atlantic Ocean; it is considered a "slow-spreading" ridge
- 2. method of dating rocks by determining the proportions of radioactive isotopes
- 3. long narrow depressions on the seafloor that form at the boundary of tectonic plates where one plate is pushed or subducts beneath another.
- 8. an intensely hot area in the mantle below Earth's crust.
- 9. a theory explaining the movement of Earth’s plates over time
- 10. where new oceanic crust is formed through volcanic activity, gradually moves away from the ridge
- 11. one of the sections of the Earth's lithosphere that is in constant motion
- 14. observed that the continents of South America and Africa looked like they would fit together remarkably well—take away the Atlantic Ocean and these two massive landforms would lock neatly together.
- 15. sudden and violent shaking of the ground.
- 17. an area on Earth where two or more lithospheric plates collide