Geologic Time Vocab

4. the age of rocks and geologic features compared with other nearby rocks and features
7. the numerical age, in years, of a rock or object
9. a piece of an older rock that becomes a part of a new rock
10. principle that sediments are deposited in large, continuous sheets in all lateral directions
11. surfaces where rock has eroded away, producing a break, or gap, in the rock record
13. a chart that divides Earth’s history into different time units based on changes in the rocks and fossils
14. a method used by geologists to fill in the missing gaps in an area’s rock record by matching rocks and fossils from separate locations
15. principle that most rock-forming materials are deposited in horizontal layers

1. a principle stating that geologic processes that occur today are similar to those that occurred in the past
2. the principle that in undisturbed rock layers, the oldest rocks are on the bottom
3. a fossil representative of a species that existed on Earth for a short length of time, was abundant, and inhabited many locations
5. the principle that if one geologic feature cuts across another feature, the feature that it cuts across is older
6. the extinction of many species on Earth within a short period of time
8. the preserved remains or evidence of past living organisms
12. a rock or sediment layer with distinctive characteristics that make it easily identifiable in correlation