Geology Review

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Across
  1. 2. fossils- formed when a mold fossil fills up with sediment
  2. 7. The geologic age of a fossil organism, rock or geologic feature or event defined relative to other organisms, rocks, or features or events rather than in terms of years
  3. 9. fossils from the remains of plants, animals and other organisms are converted into a carbon or carbon-containing residue
  4. 10. A break or fracture in the ground that occurs when the Earth's tectonic plates move or shift and are areas where earthquakes are likely to occur.
  5. 12. Atoms of the same element that have the same number of protons but different numbers of neutrons
  6. 13. A group of extinct segmented hard shelled marine arthropods that lived over 520 million years ago
  7. 15. A gap in the sequence of rock layers; The surface where new rock layers meet a much older rock surface beneath them
  8. 16. fossils formed when an object is placed into soft mud and is removed by decomposition or physical sources
  9. 17. Rocks that are subjected to high heat and pressure which causes a profound change in form
  10. 18. fossils of A plant, animal or other organism that is perfectly preserved for many years
  11. 21. A radioactive isotope which is present in organic materials and is the basis for radiocarbon dating
  12. 22. An interval of time known as the age of the reptiles from about 252 to 66 million years ago
  13. 23. The process of becoming extinct where a species comes to an end or dies out
  14. 24. Fossils that are used to define and identify geologic time periods
  15. 25. A sample of ice removed from an ice sheet most commonly in the polar ice caps of Antarctica; provides information on climate from different periods (up to almost one million years) that can be used for research.
  16. 26. Rock that has formed through the deposition and solidification of material, especially material transported by water
  17. 27. The true age of a rock or fossil
Down
  1. 1. The time taken for the radioactivity of a specified isotope to fall to half its original value
  2. 3. fossils that are Evidence of plants, animals, and other organisms in the form of preserved footprints, tracks, burrows, borings, and feces left behind rather than the actual organism’s remains
  3. 4. An era that spans about 65 million years ago also known as the age of the mammals
  4. 5. The era of time prior to 600 million years ago, covering 90 % of Earth’s history divided into three eras: Hadean, Archaean, and Proterozoic
  5. 6. Rock formations from magma that cools and solidifies within the crust of the planet
  6. 8. A system that divides Earth’s history into intervals of time defined by major events or changes on Earth.
  7. 11. A geological law that states in any undisturbed sequence of rock layers the youngest layer is on the top and the oldest layer is on the bottom
  8. 14. One of the three main rock types and formed through the cooling and solidification of magma or lava
  9. 19. The rate of decay of unstable isotopes can be used to estimate the absolute ages of fossils and rocks
  10. 20. The era, which ran from about 542 million years to 251 millions years ago, known for great change on Earth with plants becoming widespread and the first vertebrate animals colonizing land. Also known for the breaking up of a supercontinent and the formation of another