How carbon dating done


Confined as they are in these crystals, many scientists believe that the ratio of parent radioactive uranium to daughter lead atoms in zircons can be used to calculate the ages of the crystals. These tiny zirconium silicate crystals can survive seemingly intact despite erosion, changes in environment, and metamorphic conditions that radically alter most rocks. Therefore, the oldest zircons are considered to be the best indicators of what the early earth was like.

Both 13 C and 14 C are present in nature. The former accounts for about 1% of all carbon. The abundance of 14 C varies from % (one part per trillion, a small, but measurable, level) down to zero. The highest abundances of 14 C are found in atmospheric carbon dioxide and in products made from atmospheric carbon dioxide (for example, plants). Unlike 12 C and 13 C, 14 C is not stable. As a result it is always undergoing natural radioactive decay while the abundances of the other isotopes are unchanged. Carbon-14 is most abundant in atmospheric carbon dioxide because it is constantly being produced by collisions between nitrogen atoms and cosmic rays at the upper limits of the atmosphere.


How carbon dating done

How carbon dating done



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