Carbon dating news articles
It is not correct to state or imply from this evidence that the radiocarbon dating technique is thus shown to be generally invalid.
The problem with freshwater clams arises because these organisms derive the carbon atoms which they use to build their shells from the water in their environment.
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.
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.By radiocarbon dating a piece of wood which has been dated by counting the annual growth rings of trees back to when that piece of wood grew, a calibration table can be constructed to convert radiocarbon years to true calendar years.Of course, the table, so constructed, will only give the correct calibration if the tree-ring chronology which was used to construct it had placed each ring in the true calendar year in which it grew.Long tree-ring chronologies are rare (there are only two that I am aware of which are of sufficient length to be of interest to radiocarbon) and difficult to construct.They have been slowly built up by matching ring patterns between trees of different ages, both living and dead, from a given locality.