Radiocarbon dating artifacts - RADIOCARBON DATING


The different isotopes of carbon do not differ appreciably in their chemical properties. This resemblance is used in chemical and biological research, in a technique called carbon labeling : carbon-14 atoms can be used to replace nonradioactive carbon, in order to trace chemical and biochemical reactions involving carbon atoms from any given organic compound.

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.

Radioactive dating enables geologists to record the history of the earth and its events, such as the dinosaur era, within what they call the geologic time scale. In this method, the carbon sample is first converted to carbon dioxide gas before measurement in gas proportional counters takes place. Radiocarbon dating can only be used to date items back to as far as about 50,000 years old.


Radiocarbon dating artifacts

Radiocarbon dating artifacts