Radio carbon dating assumptions
AMS technology has allowed us to date very small samples (such as seeds) that were previously undatable.
Since there are practical limits to the age range of the method, most samples must be younger than 50,000 years and older than 100 years.
And finally, we must assume that there hasn't been any contamination in the specimen which we are attempting to date.
Scientific research has called the first two assumptions into question.
This discovery meant that there are three naturally occurring isotopes of carbon: Whereas carbon-12 and carbon-13 are stable isotopes, carbon-14 is unstable or radioactive.
Carbon-14 is produced in the upper atmosphere when cosmic rays bombard nitrogen atoms.
Since carbon is fundamental to life, occurring along with hydrogen in all organic compounds, the detection of such an isotope might form the basis for a method to establish the age of ancient materials.
Libby, a Professor of Chemistry at the University of Chicago, predicted that a radioactive isotope of carbon, known as carbon-14, would be found to occur in nature.
Some types of samples require more extensive pre-treatment than others, and these methods have evolved over the first 50 years of radiocarbon dating.
I'm confident that we can improve the accuracy of carbon dating somewhat, but only if we acknowledge and carefully study the various factors which may play a role in how reliable our foundational assumptions are.
In order for carbon dating to by accurate certain foundational assumptions must first be true.
Most samples require chemical pre-treatment to ensure their purity or to recover particular components of the material.
The objective of pre-treatment is to ensure that the carbon being analyzed is native to the sample submitted for dating.
Libby calculated the half-life of c14 as 5568 ± 30 years.