C14 dating coal
If this water is in contact with significant quantities of limestone, it will contain many carbon atoms from dissolved limestone.
A brief look at the original reference [Vinogradov et al., page 319.]...immediately reveals that the sample was not Pennsylvanian coal at all.Living organisms are constantly incorporating this C-14 into their bodies along with other carbon isotopes.When the organisms die, they stop incorporating new C-14, and the old C-14 starts to decay back into N-14 by emitting beta particles.When dating wood there is no such problem because wood gets its carbon straight from the air, complete with a full dose of C-14.The creationists who quote Kieth and Anderson never tell you this, however.The older an organism's remains are, the less beta radiation it emits because its C-14 is steadily dwindling at a predictable rate.
So, if we measure the rate of beta decay in an organic sample, we can calculate how old the sample is. Question: Kieth and Anderson radiocarbon-dated the shell of a living freshwater mussel and obtained an age of over two thousand years.
Radiocarbon dating can easily establish that humans have been on the earth for over twenty thousand years, at least twice as long as creationists are willing to allow.
Therefore it should come as no surprise that creationists at the Institute for Creation Research (ICR) have been trying desperately to discredit this method for years.
In actual practice, it is the amassed evidence of multiple radiocarbon dates, generally on different materials by different investigators using different measurement apparatus, which is applied to a given chronological question.
Stories of the sort above, which are obviously meant simply to discredit radiocarbon dating, are very far from the truth.
There is, in fact, no indication anywhere in the original reference that these samples were from the "Pennyslvanian"; nor is there any hint that they were expected to be "300 million years old"; these appear to be purely apocryphal embellishments to the original account.