Across
- 1. This principle states that layers of rock are superimposed, or laid down one on top of another.
- 10. The "Age of Early Life" continents formed and our modern atmosphere developed, while early life evolved and flourished during this time.
- 13. _____ ________ occurs when the nucleus of a radioactive atom spontaneously transforms into an atomic nucleus of a different, more stable isotope.
- 17. The "Age of Reptiles" Pangaea began separating into the modern continents, and the modern Rocky Mountains rose during this time.
- 18. The mineralized sediment that fills the mold recreates the shape of the remains.
- 19. The preserved remains of plants and animals whose bodies were buried in sediments, such as sand and mud.
- 20. The mineralized impression of the organism left in the sediment is called a ______.
- 21. The process of forming something by forcing or pushing it out, especially through a small opening.
Down
- 2. The "Age of Ancient Life" Fish diversified and marine organisms were very abundant during this time.
- 3. The "Age of Mammals" North America's characteristic landscapes began to develop during this time.
- 4. A type of geologic contact caused by a period of erosion or a pause in sediment accumulation, followed by the deposition of new sediments.
- 5. The “calendar” for events in Earth history.
- 6. This occurs when the organic matter is completely replaced by minerals and the fossil is turned to stone.
- 7. The time required for one-half of the radioactive (parent) isotopes in a sample to decay to radiogenic (daughter) isotopes.
- 8. The action or process of forcing a body of igneous rock between or through existing formations, without reaching the surface.
- 9. The approximate age determination of rocks, fossils or minerals made by comparing whether the material is younger or older than other surrounding material.
- 11. The measurement of geologic age in years.
- 12. A fossil that provides indirect evident evidence of ancient plants or animals, such as footprints, nests, burrows, or feces.
- 14. It is a type of fossil found in any rock when organic material is compressed, leaving only a carbon residue or film.
- 15. A mineral is used in geology to determine the degree of metamorphism a rock has experienced.
- 16. An event or a time that begins a new period or development.
- 19. A fracture or zone of fractures between two blocks of rock