geologic time

8. along cylinder of ice
9. current era, mammals, humans and is the late life
10. broken into three parts and marks the beginning of earth
13. all the fossils ever discovered on earth.
15. divides earth's history into intervals.
17. finding the absolute age of a sample by determining the relative percentages of a radioactive parent isotope and a stable daughter isotope
18. scientist who studies earth's history.
20. the most recent division of the precambrian and longest geologic eon
21. traces or remains of an organism that lived long ago, most common preserved in sedimentary rock
22. determining an object is older or younger.

1. study of the origin, history and structure of earth.
2. scientist that studies fossil remains
3. principle that states that younger rocks lie above older rocks
4. determining the actual age of an event
5. solar system was forming
6. a break in the geologic record
7. fossilized structure, such as a feetprint
11. dinosaurs and is the middle life
12. an ordered arrangement of rock layers that is based on the relative age.
14. continental plates began to form in this eon
16. states that geologic processes that happened in the past can be explained by current geologic processes.
19. means ancient life and is the early life