geological time scale

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Across
  1. 3. any feature that cuts across a sequence of rocks, younger than everything it cuts.
  2. 4. any rock or fragment that’s included inside another rock is older then the rock which is included
  3. 5. the science of the study of earth
  4. 6. forms of life which existed during limited periods of geologic time
  5. 7. the technique scientists use of determining the absolute age of a material
  6. 9. The amount of time it takes for half of a remaining isotope to decay to a daughter product.
  7. 10. a gap in the rock record
Down
  1. 1. The oldest rocks are on the bottom and the youngest rocks are on the top.
  2. 2. an igneous rock that forms when magma cools and hardens after cutting through existing rock layers
  3. 8. assigning actual dates (in years before