Across
- 2. weathering breakdown and alteration of rocks at or near Earth's surface as a result of chemical processes
- 5. Break in the geologic record created when rock layers are eroded or sediment is not deposited for a long period of time
- 6. dating Method of determining the absolute age of an object by comparing the relative percentages of a radioactive parent isotope and a stable daughter isotope
- 8. process in which carbonic acid reacts chemically with another substance
- 12. fossil Fossil that is used to establish the age of a rock layer because the fossil is distinct, abundant, and widespread, and the species that formed the fossil existed for only a short span of geologic time
- 13. Atom of a substance that has the same number of protons but a different number of neutrons as another atom of the same substance
- 14. record A historical sequence of life indicated by fossils found in layers of the Earth's crust
- 15. dating Any method of measuring the age of an event or object in years
- 17. the grinding and wearing away of Earth's surfaces through the mechanical action of other rock or sand particles
Down
- 1. of superposition States that layers of sedimentary rocks, younger rocks normally lie on top of older rocks if the layers have not been disturbed
- 3. Amount of time required for half of an original sample of radioactive material to decay or undergo radioactive transformation
- 4. Idea that geologic processes that occurred in the past can be explained by current geologic processes
- 6. dating Any method of determining whether an event or an object is older or younger than other events or objects
- 7. element Stable element into which a radioactive element breaks down
- 9. body of rock or sediment that allows the flow and stores groundwater
- 10. Time Very long period of time that Earth has existed
- 11. precipiation rain, snow, or sleet that contains a high concentration of acids
- 16. fossil Fossilized mark that formed in sedimentary rock by the movement of an animal on or within soft sediment