Earth Vocabulary

4. line: A break in Earth's crust where slabs of rock slip past each other.
5. Floor Spreading: Process by which new oceanic crust is formed at mid-ocean ridges.
6. dating: Method of measuring the age of an object in years.
9. Places where tectonic plates are moving apart.
13. Core: The solid innermost layer of the Earth.
16. Supercontinent that existed millions of years ago.
17. Process by which one tectonic plate sinks beneath another.
18. Places where tectonic plates slide past each other.
19. Rocks formed by the accumulation and cementation of mineral and organic particles.
21. Rocks that have been changed by heat and pressure.
25. Currents: Circular currents in the mantle caused by the magma being heated by the core.
26. Deep underwater troughs created by one plate subducting under another.
27. Drift: Theory that continents have moved over geologic time.

1. Tectonics: Theory explaining the movement of the Earth's plates.
2. The soft layer of the mantle on which the lithosphere floats.
3. The outermost layer of Earth.
7. Principle stating that in undisturbed layers of rock, the oldest rocks are on the bottom.
8. Openings in Earth's crust from which molten rock, ash, and gases erupt.
10. Large landforms that rise prominently above their surroundings.
11. dating: Method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock.
12. The rigid outer layer of the Earth, including the crust and upper mantle.
14. Rocks formed from the cooling and solidification of magma or lava.
15. Core: The liquid layer of the Earth's core that lies beneath the mantle.
20. Process by which rock, sand, and soil are broken down and carried away.
22. Ridge: Underwater mountain ranges formed by plate tectonics.
23. Places where tectonic plates are coming together.
24. The breaking down of rocks and other materials on the Earth's surface.