History of Earth + Geologic Time

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Across
  1. 1. ________ are subdivided into epochs.
  2. 3. A farmer and naturalist from the 1700's who first came up with an explanation for the Earth being older than 6,000 years.
  3. 6. _______ are subdivided into smaller units of time called eras.
  4. 8. The principle that when a piece of an older rock becomes part of a new rock, the rock containing the pieces is younger than the pieces.
  5. 13. Dinosaurs were abundant during the _________ era.
  6. 14. _______ are subdivided into periods.
  7. 17. When younger sedimentary layers are deposited on older igneous or metamorphic rock layers that have been eroded.
  8. 18. A principle that states that geologic processes that occur today are similar to those that have occurred in the past.
  9. 19. ________ age is the age of rocks and geologic features compared with other rocks and geologic features nearby.
  10. 20. ______ time scale is a model of Earth’s history from its origin 4.6 billion years ago to the present
  11. 22. A surface where rock has eroded away, producing a break, or gap, in the rock record.
  12. 23. Original __________ is the principle that most rock-forming materials are deposited in horizontal layers.
  13. 24. The preserved remains or evidence of ancient living things.
  14. 25. Rocks or sediment layers that are used as a marker to correlate rock layers
Down
  1. 2. The principle that in undisturbed rock layers, the oldest rocks are on the bottom.
  2. 4. Matching rocks and fossils from separate locations
  3. 5. Ice Age glaciation occurred during the ___________ era.
  4. 7. During the ___________ era, primitive fish and sharks first made their appearance.
  5. 9. _______ fossils represent species that existed on Earth for a short length of time, were abundant, and inhabited many locations.
  6. 10. Early bacteria and algae first came around in the __________ era.
  7. 11. When younger sedimentary layers are deposited on top of older, horizontal sedimentary layers that have been eroded.
  8. 12. Lateral ____________ is the principle that if one geologic feature cuts across another feature, the feature that it cuts across is older.
  9. 15. ____________ relationships is the principle that if one geologic feature cuts across another feature, the feature that it cuts across is older.
  10. 16. An idea that Earth’s history is a series of disastrous events that occurred over short periods of time.
  11. 21. ___________ unconformity occurs when sedimentary layers are deposited on top of tilted or folded sedimentary layers that have been eroded.