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