Geologic Time

3. law that says rock fragments will be older than the layers they are found in
4. amount of time smaller than an eon but larger than a period
7. period of time in the Mesozoic era and the phanerozoic era
8. smallest amount of geologic time
11. amount of geological time smaller than an era but larger than an epoch
12. Largest amount of geological time
14. used to date rocks 10 millions years old
17. atoms of elements that give off radiation from their nuclei
18. law that says in sedimentary rocks the oldest are at the bottom and the youngest at the top

1. when layers of rock bend and curve due to convection and plate movement
2. age in which the order of events is known but not the dates
5. dating used to date things very far back in time
6. the rate at which radioactive isotopes decay
9. a place in the rock record where layers of rock are missing because of uplift and erosion
10. exposed rock layers at the earth's surface
13. a thin, widespread layer of volcanic ash that can be used to correlate a specific time
15. age in which the specific dates are known
16. 14 is found in all living things