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