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The Age of Things: Sticks, Stones and the Universe

The Age of Things: Sticks, Stones and the Universe. Correcting and Using Carbon 14. http://cfcp.uchicago.edu/~mmhedman/compton1.html. Last Time:. Current Carbon-14 Fraction Original Carbon-14 Fraction. R =. Carbon 14 All Carbon. Carbon-14 Fraction =. R . A personal aside:. R .

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The Age of Things: Sticks, Stones and the Universe

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  1. The Age of Things:Sticks, Stones and the Universe Correcting and Using Carbon 14 http://cfcp.uchicago.edu/~mmhedman/compton1.html

  2. Last Time: Current Carbon-14 Fraction Original Carbon-14 Fraction R = Carbon 14 All Carbon Carbon-14 Fraction = R

  3. A personal aside: R

  4. My Answer: This says the tree from which this sample was taken was fallen ~14000 yrs ago. However, (we) cannot judge this date as valid w/o adequate context: Does this date make sense in terms of other dates at the site? For a single date is not very reliable in these situations. Furthermore, is the sample contaminated? Could there be factors that would cause the date to be erroneous? Also the date has not been properly altered to take into account fluctuations in radiocarbon levels from year to year. Finally, even if the above factors were taken into account, we only know when the tree was cut down (when it stopped taking up CO2) we have no idea how long it might have sat around before being used in a fire. Therefore, unfortunately, we cannot tell when the fire occurred with the limited data given.

  5. Measured with radioactivity or AMS methods Current Carbon-14 Fraction Original Carbon-14 Fraction R = Measured using a contemporary reference sample R

  6. Warning! Astrophysicist Talking about Tree-Rings!

  7. Correcting Carbon-14 With Tree Rings

  8. Dendrochronology

  9. Calibrating Carbon-14 Dates with Tree Rings

  10. Calibrating Carbon-14 Dates with Tree Rings

  11. Current Carbon-14 Fraction Original Carbon-14 Fraction R = R Estimated Age Estimated Ratio

  12. Current Carbon-14 Fraction Original Carbon-14 Fraction R = R Estimated Age Actual Age Estimated Ratio Actual Ratio

  13. Atmospheric Carbon-14 fraction changes with time

  14. The Changing Magnetic field

  15. Calibrating Carbon-14 Dates with Tree Rings

  16. Calibrating Carbon-14 Dates with Tree Rings

  17. Calibrating Carbon-14 Dates with Tree Rings

  18. Calibrated Carbon-14 Dates

  19. Complications

  20. Complications

  21. The Early Americans

  22. Warning! Astrophysicist Talking About Archaeology

  23. Clovis Points

  24. The Land Bridge

  25. Glaciers around 12,000 BP Clovis Mammoth kills Clovis and the Ice-Free Corridor

  26. The “Clovis-First” Model

  27. Are there Sites earlier than Clovis?

  28. Meadowcroft

  29. The MeadowCroft Rockshelter

  30. Dates at Meadowcroft

  31. Dates at Meadowcroft 1775 AD 1265 AD 1025 AD - 660 AD 285 AD - 125 BC 340 BC - 870 BC 980 BC -1305 BC 1260 BC - 6060 BC 10,850 BC - 14,255 BC +

  32. Monte Verde

  33. A Coastal Route?

  34. What is really Important about Monte Verde

  35. Monte Alegre

  36. Temporal Relationships within a site

  37. Temporal relationships between sites

  38. Rather than: How did people get into the New World? Mammoth Hunters How did people live in the New World? Forest Foragers

  39. Next Time Potassium, Argon, Genes and Walking Upright

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