Plate Tectonics

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.

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