Some expected developments are likely to include additional standardization of laboratory methods and procedures, improved standards of calibration and correction of radiocarbon dates, better understanding of secular variations of radiocarbon, and some extension of the range of the method although the common practical limit will probably remain at 30,000 to 50,000 years BP.
The occurrence of natural radioactive carbon in the atmosphere provides a unique opportunity to date organic materials as old as roughly 60,000 years.
His success initiated a series of measurements designed to answer two questions: Is the concentration of carbon-14 uniform throughout the plant and animal kingdoms?
And, if so, has today’s uniform level prevailed throughout the recent past?
After showing the essential uniformity of carbon-14 in living material, Libby sought to answer the second question by measuring the radiocarbon level in organic samples dated historically—materials as old as 5,000 years from sources such as Egyptian tombs.
With correction for radioactive decay during the intervening years, such old samples hopefully would show the same starting carbon-14 level as exists today. His conclusion was that over the past 5,000 years the carbon-14 level in living materials has remained constant within the 5 percent precision of measurement.
So low is such a carbon-14 level that no one had detected natural carbon-14 until Libby, guided by his own predictions, set out specifically to measure it.
On the positive side, however, the recognition of problems has led to a better understanding of the method and significant improvements have been made with regard to both precision and accuracy of radiocarbon dating.
Current active research on many problems by different laboratories, and especially the concerted efforts directed towards solving specific problems by groups of laboratories clearly indicate the healthy condition of the radiocarbon dating field.
Unlike most isotopic dating methods, the conventional carbon-14 dating technique is not based on counting daughter isotopes.
It relies instead on the progressive decay or disappearance of the radioactive parent with time.