Across
- 3. A system of chronological dating that relates geological strata to time, used by geologists to describe the timing and relationships of events in Earth's history.
- 4. Determining the age of a fossil or rock relative to another by examining its position in layers of rocks or strata.
- 7. The theory explaining the movement of the Earth's plates that has caused the formation and break-up of continents and oceans over millions of years.
- 10. The study of rock layers (strata) and the sequence of events they reflect.
- 11. A division of geological time into which eras are subdivided.
- 13. The history of life as documented by fossils, the remains or imprints of organisms from earlier geological periods preserved in sedimentary rock.
- 14. A period in Earth's history when a large number of species die out in a relatively short time.
- 15. The gradual movement of continents across Earth’s surface through geological time.
Down
- 1. Rock formed by the accumulation and compaction of sediment, often containing fossils.
- 2. Large plates of Earth's lithosphere that move over the asthenosphere.
- 5. A major division of geologic time, smaller than an eon.
- 6. The largest division of geologic time, spanning hundreds of millions of years.
- 8. A smaller division of geological time; a subdivision of a period.
- 9. A method used to date rocks and other objects based on the known decay rate of radioactive isotopes.
- 12. Remains or impressions of ancient organisms preserved in rock.