Chapter 1 Plate Tectonics

1. a layer of molten iron and nickel that surrounds the inner core of Earth
7. a plate boundary where two plates move past each other in opposite directions
8. a dense sphere of solid iron and nickel at the center of Earth
11. a dark, igneous rock with a fine texture found in oceanic crust
14. the name of the single landmass that broke apart 200 million years ago and gave rise to today’s continents
16. a rigid layer made up of the uppermost part of the mantle and the crust
17. country that is being split apart at the Mid-Atlantic ridge
19. the force exerted on a surface divided by the area over which the force is exerted
21. a trace of an ancient organism that has been preserved in rock
23. a deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle
24. the amount of mass in a given space, mass per unit of volume (like g/cm3)
25. the process by which molten material adds new oceanic crust to the ocean floor
28. the theory that pieces of Earth’s lithosphere are in constant motion, driven by convection currents in the mantle
29. the transfer of heat by movement of a fluid
32. a well-tested concept that explains a wide range of observations
33. name of the ship that took rock samples from the deep ocean floor
34. the hypothesis that the continents slowly move across Earth’s surface

2. the transfer of heat within a material or between materials that are touching
3. the transfer of energy through space
4. the process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary
5. a section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental crust
6. a usually light-colored igneous rock that is found in continental crust
9. a plate boundary where two plates move toward each other
10. a break in the Earth’s crust where masses of rock slip past each other
12. vibrations that travel through Earth carrying the energy released during an earthquake
13. the layer of hot, solid material between Earth’s crust and core
15. first scientist to hypothesize about continental drift
18. the layer of rock that forms Earth’s outer surface
20. a deep valley that forms where two plates move apart
22. a device that determines the distance of an object under water by recording echoes of sound waves
26. An undersea mountain chain where new ocean floor is produce; a divergent plate boundary
27. a plate boundary where two plates move away from each other
30. the movement of a fluid caused by differences in temperature, that transfers heat from one part of the fluid to another
31. the soft layer of the mantle on which the lithosphere floats