Unit 4

2. a geological feature is younger than the rock layers it cuts through
4. sedimentary rock layers are initially deposited in a continuous, unbroken sheet across a wide area
10. a method used to determine the age of an object or event by comparing it to others, establishing an order of events rather than providing a specific numerical age
11. the principle that a quantum system can exist in multiple states at once until it is measured
15. a technique used to determine the age of materials by measuring the decay of radioactive isotopes within them
16. a geological and ecological boundary separating the state's hard, rocky Piedmont region from the sandy Coastal Plain
17. the original, unstable radioactive isotope that undergoes radioactive decay to form a more stable "daughter" isotope
18. The more stable isotope that is created from the parent isotope's decay.

1. sedimentary rock layers are deposited in horizontal or near-horizontal layers due to gravity
3. a fossil from an organism that lived for a short, well-defined geologic time period and was geographically widespread
5. a method used in archaeology and geology to find the actual age of an object in years
6. a gap or break in the geologic rock record, caused by a period of erosion or a pause in sediment deposition, followed by renewed deposition
7. a radioactive isotope of carbon that emits beta radiation and has a half-life of 5730 years, decaying to nitrogen-14
8. the time it takes for half of a substance to undergo a process
9. the most common, naturally occurring, and stable isotope of uranium
12. preserved remains, impressions, or traces of once-living things from past geological ages
13. the scientific principle that the same natural laws and processes that operate today have always operated throughout the past and will continue to operate in the future
14. formed from pre-existing rocks or organic matter that accumulate as sediment, which is then compacted and cemented together over time