Since no reliable historically dated artifacts exist which are older than 5,000 years, it has not been possible to determine the relationship of radiocarbon years to calendar years for objects which yield dates of tens of thousands of radiocarbon years.Thus, it is possible (and, given the Flood, probable) that materials which give radiocarbon dates of tens of thousands of radiocarbon years could have true ages of many fewer calendar years. The shells of live freshwater clams have been radiocarbon dated in excess of 1600 years old, clearly showing that the radiocarbon dating technique is not valid.MYTH #2 Radiocarbon dating has established the date of some organic materials (e.g., some peat deposits) to be well in excess of 50,000 years, thus rendering a recent creation (6 to 10 thousand years ago) impossible.Some organic materials do give radiocarbon ages in excess of 50,000 "radiocarbon years." However, it is important to distinguish between "radiocarbon years" and calendar years.Other radiometric dating methods such as potassium-argon or rubidium-strontium are used for such purposes by those who believe that the earth is billions of years old.Radiocarbon is not suitable for this purpose because it is only applicable: a) on a time scale of thousands of years and b) to remains of once-living organisms (with minor exceptions, from which rocks are excluded).It is not difficult to see how such a claim could arise, however.
Since limestone contains very little, if any, radiocarbon, clam shells will contain less radiocarbon than would have been the case if they had gotten their carbon atoms from the air.Some may have mistaken this to mean that the sample had been dated to 20,000 radiocarbon years.The second characteristic of the measurement of radiocarbon is that it is easy to contaminate a sample which contains very little radiocarbon with enough radiocarbon from the research environment to give it an apparent radiocarbon age which is much less than its actual radiocarbon age.The field of radiocarbon dating has become a technical one far removed from the naive simplicity which characterized its initial introduction by Libby in the late 1940's.
It is, therefore, not surprising that many misconceptions about what radiocarbon can or cannot do and what it has or has not shown are prevalent among creationists and evolutionists - lay people as well as scientists not directly involved in this field.
First, any instrument which is built to measure radiocarbon has a limit beyond which it cannot separate the signal due to radiocarbon in the sample from the signal due to background processes within the measuring apparatus.