1. Chapter 9: View of Earth’s Past Megan Darvish June 1

2. Geologic Column Represents a timeline of Earth’s history Invented in the 19 th century Oldest rock at top bottom Newest rock at the top Distinguished by the type of rock and kinds of fossils Fossils in more recent layers are modern day plants/animals

3. Using a Geologic Column Uses ages of rock layers Radiometric dating Compare two similar rocks together; if matched, probably from same time period

4. Divisions of Time Marked by climate, Earth’s surface, and types of organisms So long scientists use abbreviations Separated into periods/eras

5. Major Elements of Column Precambrian Tertiary Mesozoic Permian Cenozoic Carboniferous Paleozoic Devonian Cretaceous Silurian Jurassic Ordovician Triassic Cambrian Quatemary

6. Law of Superposition States that older rock layers will sink to the bottom of the strata due to age. Intrusions are youngest, most often.

7. Eon Period in time marked by major events Precambrian Eon Lasted approx. 4,058 million years Cambrian Eon From when the Precambrian Eon ended until present day

8. Era Important time periods within an eon Paleozoic Lasted 251 million years Mesozoic Lasted 65.5 million years Cenozoic Present day

9. Period Cambrian- 542 million years Ordovician- 488 million years Silurian- 444 million years Devonian- 416 million years Carboniferous (includes Pennsylvanian and Mississippian)- 677 million years Permian- 299 million years Triassic- 251 million years

10. Period Jurassic- 200 million years Cretaceous- 146 million years Tertiary- 183.5 million years Quaternary- approx. 1.8 million years

11. Epoch Only in the Cenozoic Era Longer than an age; shorter than a period Divided into ages- events of distinct fossils in the fossil record 7 total 5 in the Tertiary Period 2 in the Quaternary Period

12. Epoch Tertiary: Paleocene- 65.5 million years Eocene- 55.8 million years Oligocene- 33.9 million years Miocene- 23 million years Pliocene- 5.3 million years

13. Epoch Quaternary: Pleistocene- 1.8 million years Holocene-.0115 million years

14. When do I live? Cenozoic Era Quaternary Period