I have only skimmed the article, but how do they address mechanisms known to add carbon-14 to old carbon?This is evidently a paper using the data from multiple sources and analyzing the whole.
Here is an example cited from the paper.
Most of their foraminifera were from a Pleistocene core from the tropical Atlantic off the northwest coast of Africa dated at 455,000 years. The foraminifera from this core showed a range of 14C values from 0.16 to 0.4 pmc with an average, taken over 115 separate measurements, of 0.23 pmc. A benthic species of foraminifera from another core, chosen because of its thick shell and smooth surface in the hope its ‘contamination’ would be lower, actually had a higher average 14C level of 0.58 pmc!
The authors then performed a number of experiments involving more aggressive pre-treatment of the samples to attempt to remove contamination. These included progressive stepwise acid hydrolization of the carbonate samples to CO2 gas and 14C measurement of each of four separate gas fractions. They found a detectable amount of surface contamination was present in the first fraction collected, but it was not large enough to make the result from the final gas fraction significantly different from the average value. They also leached samples in hydrochloric acid for two hours and cracked open the foraminifera shells to remove secondary carbonate from inside, but these procedures did not significantly alter the measured 14C values.
The authors summarize their findings in the abstract of their paper as follows, “The results…show a species-specific contamination that reproduces over several individual shells and foraminifera from several sediment cores. Different cleaning attempts have proven ineffective, and even stronger measures such as progressive hydrolization or leaching of the samples prior to routine preparation, did not give any indication of the source of contamination.” In their conclusion they state, “The apparent ages of biogenic samples seem species related and can be reproduced measuring different individuals for larger shells or even different sediment cores for foraminifera. Although tests showed some surface contamination, it was not possible to reach lower 14C levels through cleaning, indicating the contamination to be intrinsic to the sample.” They continue, “So far, no theory explaining the results has survived all the tests. No connection between surface structure and apparent ages could be established.”
The measurements reported in this paper obviously represent serious anomalies relative to what should be expected in the uniformitarian framework. There is a clear conflict between the measured levels of 14C in these samples and the dates assigned to the geological setting by other radioisotope methods. The measured 14C levels, however, are far above instrument threshold and also appear to be far above contamination levels arising from sample processing. Moreover, the huge difference in 14C levels among species co-existing in the same physical sample violates the assumption that organisms living together in the same environment should share a common 14C/C ratio. The position the authors take in the face of these conflicts is that this 14C, which should not be present according to their framework, represents ‘contamination’ for which they currently have no explanation.
Contamination by excess 14C should make the item appear to be younger that it really is. If it is not contamination then it is younger than whatever method considers it older.
OK, after a very busy day, I've read through the paper.
We have one fact which is observed: samples from coal seams, and other sampes of very old carbon of a biological origin, seem to contain a nonzero amount of
14C. This fact can't be chalked up to instrument error; elaborate steps are taken to account for systematic error, and the statistics render the random error smaller than the quantities detected.
That being said, we have to examine possible explanations. These are:
- The radiocarbon ages measured are the actual ages of the samples.
- Carbon-14 has somehow been added to the sample . (Or subtracted, but that's not the direction of change we're interested in.)
- One or more of the assumptions underlying radiocarbon dating is flawed.
- Something else.
There are a number of dating methods which can be applied to coal seams and other sources of ancient carbon. Comparison with overlying and underlying strata of igneous rock, for example, can "pinch" the age of the carbon deposit between ages that can be determined by the use of other radiometric clocks. The ages yielded for coal seams, for example, are incompatible with the radiocarbon ages. Explanation 1 is seriously downgraded, if not rejected altogether.
Extra
14C could be added by a number of possible methods. Modern water seeping through a coal seam could conceivably exchange dissolved carbon with carbon from the seam. Since dissolved CO
2 makes the water slightly acid, this is not too unreasonable.
Another possibility involves the presence of uranium and other radioactive materials which synthesize
14C
in situ. And indeed, a report I saw mentioned in the talk.origins newsgroup mentions that the background
14C correlates better with concentrations of uranium than anything else.
Is it surprising that uranium would show up in and around carbon of biological origin? Not terribly. When I was learning health physics in college, one of the things I studied was the tendency for living organisms to concentrate particular elements from the environment. Phosphorus, for example, was found in fish at concentrations up to 30,000 times higher than in the surrounding water. If you want to assess the fraction of phosphorus that is
32P, rather than filtering 30,000 gallons of sea water, you could process one gallon of native fish. Uranium and other radioactive metals are also taken up by living things. Indeed, this is one of the concerns of radioactive contamination -- radioactive elements often follow the same pathways non-radioactive elements do.
I suppose it's even possible some evil force is creating small amounts of
14C
in situ to fool us all. Maybe that's what Screwtape was demoted to after that miserable failure of a nephew he produced. :-)
The paper does postulate one assumption in radiometric dating the authors believe to be faulty -- that rates of decay have been constant.
At the bottom of page 11, the authors speculate that all radioactive elements might, during the Flood, have undergone accelerated decay, and this acceleration would have been proportional to the half life.
...if 40K, for example, underwent 400 Ma of decay during the Flood relative to a present half-life of 1250 Ma, then 14C would have undergone (400/1250)*5730 years = 1834 years of decay during the Flood.
(Note: if you do the algebra, you'll find this implies 20% of all radionuclides disappeared during the Flood. The half-life terms cancel out.)
We're starting to get into cafeteria science here. While nuclides are decaying, they're also releasing energy. Most, if not all, of the heat in the interior of the earth comes from radioactive decay. U-238, with a half-life of 4*10
9 years is a significant contributor. What is the effect on the planet of cramming 1.44 billion years' energy release into a little over one year? How about Thorium with a half-life of 14.4 billion years? That crams 4.5 billion years of energy release into a little over a year.
Shall I look up the natural abundances and calculate how much energy that is to infuse into the planet?
Another side-effect, which should be readily calculable, has to do with nuclear decay series. One of the nuclides in the decay series of U-238 is U-234. It has a half-life of some 247,000 years, and is found in nature in secular equilibrium with U-238.
If there had an event which had perturbed radioactive decay rates as suggested in the article you cite, we should see considerably more U-234 in nature -- about a billion times more than we see now.
With a little more work, I could come up with countless examples, without even addressing the effects we should expect to see when we try to date rock samples by radiometric methods.
Certainly, this aspect of the authors' model is falsified.
I think for the time being, it looks like radioactive elements behave just the way the "uniformitarian model" holds they do.