Across
- 2. Any method of determining whether an event or object is older or younger that other events or objects.
- 4. The scientific study of origin, history, and structure of Earth and the process that shape Earth.
- 7. A principal that states younger rocks lie above older rocks if the layers have not been disturbed.
- 9. The weather conditions in an area over a long period of time
- 10. A break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time.
- 11. A long cylinder of ice obtained from drilling through ice caps or ice sheets used to study past climates.
- 13. The time required for half of a sample of a radioactive isotope to break down by radioactive decay to form a daughter isotope.
- 14. Any method of measuring the age of an event or object in years.
- 15. A principle that Geologic processes that occurred in the past can be explained by current geologic processes.
Down
- 1. An ordered arrangement of rock layers that is based on the relative ages of rocks in which the oldest rocks are at the bottom.
- 3. The trace or remains of an organism that lived long ago are most commonly preserved in sedimentary rock.
- 5. The standard method used to divide Earth’s long natural history into manageable parts.
- 6. The process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element
- 8. A method if determining the absolute age of an object by comparing the relative percentages of a radioactive isotope
- 12. A Fossilized structure such as a footprint or coprolite that formed in sedimentary rock by an animal on or within soft sediment.