chapter 13

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chapter 13
2011-11-02 20:21:37

geological time
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  1. about how billions of years ago was rocks formed on earth?
  2. what is relative dating?
    system of reasoning that is used to determine the chronological sequence or order f a series of gerologic events
  3. what is radiometric dating?
    • numerical dating
    • uses radioactive decay of radioactive isotopes within minerals to calculate chronological age
  4. explain the pleozoic eon:
    • about 550 million years ago= start
    • tranformed single cell to multi cellular life
    • simple to diverse
  5. explain mesazoic eon:
    • middle life
    • dinosaur extinct
  6. explain cenozoic eon:
    whats happening now
  7. when did archbishops james ussher say was exact date of earth creation?
    nightfall preceding 23 october 4004 BC
  8. in 1700 what what did technique philosopher, naturalist and geologist use to get theories of deep time?
    relative dating
  9. in 1900 what did geologist use to get the age of the earth?
    • radiometric dating
    • 4.55-4.6 by
  10. what are the five funadmental geologic events ordered by relative dating?
    • intrusion-igneous rock
    • erosion-removal of rocks
    • deposition-sediment being deposited
    • faulting
    • rock deformation
  11. what are the seven stratigraphic principles used in relative dating?
    • principle superposition
    • principle of original horizontality
    • principle or original lateral continuity
    • principle of cross cutting relationships
    • principle of inclusions
    • principle of unconformities
    • principle of faunal succession (evolution)
  12. eplain principle superposition:
    youngest rock on top and oldest on bottom
  13. explain principle original lateral continuity
    • laterally continous
    • erosion cutting downward
  14. explain principle of original horizontality:
    horizontal strata on top and deformed strata on bottom
  15. explain principle of cross cutting relationships
    • igneous dike cuts across- has to be younger
    • most useful
  16. explain principle of inclusion
    • intrusion
    • granite at surface expoed to weathering
    • sandstone deposited on granite
    • older
  17. explain principle of unconformity
    rock layers deposited, folded, eroded and covered with new depostion
  18. which period is the beginning of the peleozoic?
  19. which period is beginning of the mesozoic?
  20. what is radioactive decay
    one neutron decays and turn into something else
  21. radiometric dating uses _______ to estimate age of geologic samples
    radioactive decay
  22. what is half life
    time it takes to have half of original atoms
  23. what provides important isotopic clocks
    • potassium argon
    • carbon
  24. what is the key point about why patssium-argon are useful
    used to date igneous rocks
  25. how many isotopes are there
  26. which isotope is most common
    carbon 12
  27. about how many years old is the oldest mineral
    about 4.4 bya
  28. about how old is the oldest rock
    about 4.2 bya