Correspondence: Radiocarbon

February 2, 2007

To whom it may concern,

I am very interested in the recent discoveries that shed some light on the truth behind radiocarbon dating. I was unable, however, to find the scientific papers to which you have made reference on your web site, which have conducted controversial research. I would greatly appreciate if you could send me the journal names, volume, and issue, etc. Thank you for your time.

Michael

Hello Michael,

Look here https://www.biblicalchronologist.org/about/bio.php under PUBLICATIONS. Numbers 1 and 3 should be of special interest.

Dr. Aardsma

February 21, 2013

Dear Dr. Aardsma:

I am writing to you with regard to a presentation that was give at the Western Pacific Geophysics Meeting in Singapore on August 15, 2012 by the Paleochronology Group. Specifically, they have carbon 14 dated organic material found in dinosaur bones. For the specimens tested so far, they report radiocarbon ages between 22,000 and 39,000 years before present (BP).

It should be noted that this presentation was made at a mainstream Geophysics and Geology conference. Also, the Paleochronology Group is a little different from strict young earth creationist groups, like ICR and AIG. They accept big bang cosmology and an old universe and earth, but they also believe that the earth's biosphere was intelligently designed by God in six literal days 50,000 or less years BP. They furthermore believe that this biosphere was subsequently destroyed in a world catastrophe (presumably the Genesis Flood), which deposited most of the Phanerozoic Geological Column.

I realize that you have expertise in radiocarbon dating, and I am wondering how to respond to their report. Do you think it is valid or not? I am asking in the interest of defending good science. I would note that the Paleochronology Group has issued a challenge to other scientists to the effect that if they doubt this data, they should conduct their own carbon 14 research on dinosaur bones and find out what dates they obtain.

Sincerely,
Robert

Dear Robert,

The radiocarbon "dates" on dinosaur bones reveal only the level of modern carbon contamination in the measured samples, not anything meaningful about their age.

Here is the problem. We are bathed in modern radiocarbon. It is in the air, in the plants around us, in living microbes, etc. Someone digs up an old bone. It has been buried in the ground, percolated by (modern radiocarbon) humic acids leached by rainwater, open to (modern radiocarbon) soil gases, and probably colonized by (modern radiocarbon) microbes and fungi. They submit it for measurement of radiocarbon.

How does the measurement technician separate all the modern (contaminant) radiocarbon from the old bone, intrinsic radiocarbon he wants to measure? He uses special acid dissolving protocols, and the like, which do a pretty good job of separating intrinsic sample carbon from contamination carbon, but he is working in a sea of modern carbon in the lab, and experience has shown that in practice it is impossible to get rid of 100% of modern, contaminant radiocarbon.

This is not a problem for relatively young samples --- those of interest to biblical archaeology, for example. A little modern contamination does not noticeably affect the radiocarbon measurement, because, being relatively young (i.e., young relative to the 5730 year half-life of radiocarbon) these samples have lots of sample radiocarbon to measure. Adding a little contamination to a lot of sample radiocarbon does not much change the total amount of radiocarbon measured, and hence does not much affect the date of the sample.

But if a sample is very old (i.e., relative to the 5730 year half-life of radiocarbon) and thus has zero intrinsic radiocarbon (because it has all decayed away), then the contamination component becomes the entire radiocarbon sample. One will not obtain a true age for the sample. One will obtain merely a measure of the residual modern carbon left in the sample after the technician's best efforts to get it all out.

A sample from an organism which has just died has intrinsic radiocarbon equal to 100% of what it had while living. A 5730 year-old sample has intrinsic radiocarbon equal to 50% of what it had while living. An 11,460 year-old sample has intrinsic radiocarbon equal to 25% of what it had while living. ... A 22,000 year-old sample has intrinsic radiocarbon equal to 7.2% of what it had while living. A 39,000 year-old sample has intrinsic radiocarbon equal to 0.9% of what it had while living.

This means that if an infinitely old sample contains just 0.9% modern (contamination) carbon relative to its intrinsic carbon after sample preparation is complete, it will appear to be 39,000 years old.

Just how "old" the dinosaur bone appears to be will be entirely dependent on how good a job the technician does in preparation of the sample for dating. Since the radiocarbon lab is paid a flat fee per sample by the person submitting the sample, you can be sure the technician will simply run the sample through the standard procedure, which will be none too elaborate.

If someone wanted to pay a lot of money for more elaborate sample preparation, they could probably get the radiocarbon "age" of the bone pushed back to 45,000 or even possibly 50,000 years. The radiocarbon literature contains examples of very elaborate and expensive techniques which have been able to push the radiocarbon "age" of "infinitely" old samples (anthracite coal) back to roughly 75,000 years. [If you wish to pursue this further, start with my long-ago ICC paper: G.E. Aardsma, "Search for Radiocarbon in Coal," The Proceedings of the Third International Conference on Creationism (Pittsburgh: Creation Science Fellowship, 1994), 1--8.] Standard AMS radiocarbon dating techniques routinely give results in the same range as the dinosaur bone dates you have mentioned for similar "infinitely" old samples.

All of this is common knowledge to radiocarbon scientists. It means that using radiocarbon to "date" dinosaur bone is a pretty foolish proposal at the outset. It is rather an embarrassment, therefore, to have radiocarbon dates on dinosaur bone trotted out as evidence of the relative youthfulness of dinosaur bones by creation scientists.

Trust this helps.

Sincerely,
Dr. Aardsma