Across
- 3. Any method of measuring the age of an event or object in years
- 4. The scientific study of the origin, history, and structure of Earth and the processes that shape Earth
- 7. A method of determining the absolute age of an object by comparing the relative percentages of a radioactive (parent) isotope and a stable (daughter) isotope
- 9. 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
- 11. The process in which 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; usually to study past climates
- 13. A principle that states that younger rocks lie above
- 14. The trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock
Down
- 1. The standard method used to divide Earth’s long natural history into manageable parts
- 2. A break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time
- 5. A principle that geological processes that occurred in the past can be explained by current geological processes.
- 6. The time required for half of a sample of a radioactive isotope to break down by radioactive decay to form a daughter isotope
- 8. The weather conditions in an area over a long period of time
- 10. A fossilized structure, such as a footprint or a coprolite, that formed in sedimentary rock by animal activity on or within soft sediment
- 11. Any method of determining whether an event or object is older or younger than other objects and events