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As in everything scientific,

Radiocarbon Dating has its Limitations.

 

• The first limitation is size.  Although new dating techniques have been developed which only use very small samples for dating, it is always better to have a larger sample.  Purification and distillation of the sample removes some of its matter, therefore very small samples can be deteriorated to nothing.
• Secondly, contamination of the sample is a significant problem.  Great care must be taken while handling the samples to avoid contamination with more recent carbon.  The area in which the sample was found must also be carefully examined to determine if the sample may have been mixed with samples of carbon from a later or earlier period.
• The third limitation of radiocarbon dating is that since the decay of carbon is logarithmic it has critical upper and lower limits.  Radiocarbon dating can not date recent objects or very old objects (over 50,000 years).  In less than approximately 50 years not enough C-14 has decayed for there to be a measurable difference.  Likewise after 50,000 years (or approximately 9 half lives) there is not enough C-14 left in the sample to be measured.  This makes it difficult to obtain accurate readings.  The older, and younger samples have larger errors in their readings.  The following table highlights the error relative the the age of the sample.

 

Age (yr)	Radiocarbon date rounded to	Error (± value)
0 - 1000	nearest 10	nearest 5 up
1000 - 10000	nearest 10	nearest 10 up
10000 - 25000	nearest 50	nearest 10 up
>25000	nearest 100	nearest 50 up

• The fourth limitation is the one that has fueled radiocarbon dating skeptics the most.  Radiocarbon dating assumes that the ratio of C-14 to C-12 in the atmosphere is constant, which it is not.  Originally it was thought that this was true, but recently it has been proven that this ratio has fluctuated inductively throughout the earth's history.  This fluctuation is caused by the changes in the amount of cosmic radiation that hits the earth.  For example, because of the recent decrease in the earth's ozone layer the amount of C-14 in our atmosphere is expected to be significantly different from the amount 20 or 30 years ago.  However, in the past 15-20 years dates obtained by radiocarbon dating are being calibrated in attempt correct this flaw.
• Lastly, radiocarbon dating is not 100% accurate.  It is the most common and widely-used dating technique.  Much more trustworthy dates are obtained when used in connection with other dating techniques.  It is also advised to, when possible, take several samples from the same area to be tested and use the dates from these to obtain an estimate. 

 

Although radiocarbon dating has its limitations it is still undoubtedly an indispensable tool in many fields, and has dated many major historic events.  Radiocarbon dating has ended countless debates and has given us a new perspective on prehistoric events.