Science Crossword Puzzle

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Across
  1. 4. rock formed when magma forces its way into sedimentary rock and hardens below or on the earths surface
  2. 6. rock formation that forms on the earths surface
  3. 9. by which an unstable nucleus gives off nuclear radiation
  4. 10. of fossil that forms when sediments fill in the cavity left by a decomposed organism
  5. 11. dating/Any method of determining whether an event or object is older or younger than other events or objects
  6. 12. of time required for half of an original sample of radioactive material to decay or undergo radioactive transformation
  7. 14. disappearance of a species
  8. 17. turned to stone
  9. 20. time/Very long period of time the Earth has existed
Down
  1. 1. record/Historical sequence of life indicated by fossil found in layers of Earth's crust
  2. 2. element/Element whos atoms have an unstable nucleus, which decays
  3. 3. in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time
  4. 5. formed in a rock by a dissolved organism that leaves an empty shape, showing its outward space
  5. 7. fossil/Fossilized mark that formed in sedimentary rock by the movement of an animal on or within soft sediment
  6. 8. that geologic processes that occurred in the past can be explained by current geologic processes
  7. 13. core/Loong cylinder of ice obtained from drilling through ice caps or ice sheets: used to study past climates
  8. 15. or traces of past plant nd animal life that has been preserved in sedimentary rock
  9. 16. of sedimentary rocks
  10. 18. dating/Any method of measuring the age of an event or object in years
  11. 19. element/stable element into which a radioactive element breaks down