Geologic Time and Relative Dating

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Across
  1. 3. states that an inclusion is younger than the rock it cuts across
  2. 6. When a layer of sedimentary rock overlies a layer of igneous or metamorphic rock, such as granite or marble, the eroded surface is easier to identify
  3. 7. when 75% or more of organisms disappear from the fossil record in a short time frame
  4. 9. A record of Earth’s history from its origin 4.6 bya (billion years ago) to the present
  5. 12. eras are divided into these increments of time, typically tens of millions of years
  6. 14. When a horizontal layer of sedimentary rock that overlies another horizontal layer of sedimentary rock that has been eroded
  7. 15. the order in which geologic events occurred
  8. 17. buried surfaces of erosion - the rock immediately above the unconformity is sometimes considerably younger that the rock immediately below it
  9. 18. The matching of rock outcrops or fossils exposed in one geographical region to similar outcrops or fossils exposed in other geographic regions
  10. 19. When rock layers are deposited over wide geographic areas as a result of a large meteorite strike, volcanic eruption, or other brief event
Down
  1. 1. In undisturbed horizontal sedimentary layers, the oldest layer is at the bottom and the youngest layer is at the top
  2. 2. When horizontal layers of sedimentary rock are deformed during mountain building or other geologic events, involving compressional forces, they are uplifted and tilted
  3. 4. the three earliest eons grouped together, which forms 90% of geologic time
  4. 5. States that geological processes occurring today have been occurring since Earth formed 4.6 billion years ago
  5. 8. The principle that sedimentary rocks are deposited in horizontal or nearly horizontal layers due to the geological forces
  6. 10. smallest divisions of geologic time on the geologic timescale in class
  7. 11. States that the fragments, called inclusions, in a rock layer must be OLDER than the rock layer that contains them
  8. 13. Next largest units of time in the geologic time scale
  9. 16. Largest of the units of time in the geologic time scale and encompasses all the other units of time