vocab #3

5. The trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock
6. is A principle that geologic processes that occurred in the past can be explained by current geologic processes
7. is Any method of determining whether an event or object is older or younger than other events or objects
8. A fossilized structure, such as a footprint or a coprolite, that formed in sedimentary rock by animal activity on or within soft sediment
10. A method of determining the object by comparing the relative percentage of a radioactive isotope and stable isotope
12. An ordered arrangement of rocks layers that is based on the relative ages of the rocks and in which the oldest rocks are at the bottom
14. The weather conditions in an area over a long period of time

1. The process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element
2. A principle that states the younger rocks lie above older rocks if the layers have not been disturbed
3. Any method of measuring the age of an event or object in years
4. The time required for half of a sample of a radioactive isotope to break down by radioactive decay to form a daughter isotope
9. The scientific study of the origin, history, and structure of the earth and the processes that shape the earth
11. The standard method used to divide earth’s long natural history into manageable parts
13. A break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time
15. A long cylinder of ice obtained from drilling through ice caps or ice sheets; used to study past climate