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Q: Recently I read a book called C14-Crash by Christian Bloess and Hans-Ulrich Niemitz (there is a summary in German with figures on
A: Thanks for pointing to the English translation (it was not easy to find it though).
I feel I have to reply to that, though much of the questions were discussed earlier.
This is a rather big paper, and I cannot obviously address every point, so I'll stick to major things only.
And one more comment. I thought first those guys were from the field. I haven't heard the names before, but obviously I couldn't have known everybody. But while
reading I realised they are not of this area at all, and when I got to the later sections it became obvious they are not even scientists, more probably journalists.
Anyway, back to business.
Here are the main statements they are fighting with:
The evidence of the C14 method was originally made dependent on the following 5 prerequisites:
1. Measurability: The C14 radiation to be measured must differentiate itself distinctly from the background radiation in order to measure exactly and to receive a
definite determination of age. (Problems of C14 laboratories with their results on replicated measurements)
2. Cutting Off: During its storage period between the time when it died and the corresponding investigation today, the sample under investigation may not have had
any exchange of carbon (Problem of contamination)
3. Spatial Invariance by Instantaneous Distribution: There must have been the same C14/C12 ratio in all organisms which lived simultaneously at different places
(Problems arising from comparing different hemispheres, reservoir effects).
4. Organic Invariance: There must have been the same C14/C12 ratio in all different organisms which lived simultaneously at the same place (Problem of "isotopic
fractionation").
5. The Fundamental Assumption: The C14/C12 ratio must have always been the same in the past. From this follows the statement: "The appropriate age can be
directly calculated from a C14 value." (Problem of the "Suess Effect", C14 fluctuations around the theoretical value in long tree-ring sequences).
My brief comments to that. Yes these are the basics, however some extra wording must be added.
1. The situation is much better now than it was a decade or two ago. Constant laboratory intercalibrations improved the situation a lot. I've said this before. The
introduction of the new technology - Accelerator Mass-Spectrometry (AMS) also changed many things. Like background, sample size, etc.
2. Contamination per se is a problem, who argues. However it does not mean that the method itself is invalid. Proven uncontaminated samples still remain. Also there
were significant improvements recently, certain agreements on uniforn chemical pretreatments, and most of all introduction of AMS. AMS aloowed to work with
samples of up to 10 microgram of carbon size as opposed to tens of grams for conventional decay counting. Such an advance allowed significant progress in
avoiding contamination in many cases.
Authors opinion that there might be some migration of material within the tree trunk from one ring to another is rather outdated. At the moment this question is
investigated thoroughly. It has been found that there are migratory fractions (like oils, lignin) and absolutely solidly fixed ones (e.g. alpha-cellulose). Of course only
such fractions are used for calibrations and dating. Experiment was done by measuring sequential tree-rings for the bomb pulse leading edge epoch, when
atmospheric radiocarbon nearly doubled in just 2 years (normal natural variations are 1-2% within a decade). No migration of stable fractions was found.
3. Will discuss later.
4. Isotopic fractionation is known and characterised. More and more data for more and more organisms are collected. It is a required procedure to get delta13C
measurements for a sample together with 14C determinations. Without this correction no data is reported.
5. Also, let us discuss slightly later.
Radiocarbon measurements are used in dendrochronology. Everyone admits that. However, these dendroscales constructed on radiocarbon measuremets are never
used for radiocarbon calibration. Besides, if principle 3 is correct, you do not need many calibration curves.
Accusing researches from the Uni of Arizona in hiding something, simply because they have produced results so fast is simply indecent. I know these people
personally (Long, Damon, Hughes), and know their scientific objectivity and accuracy. The American chronology was constructed so fast simply because this
bristlecone pine gave such an excellent material. Also, the first tree was not cored, but cut (by accident, actually) and immediately gave scale to nearly 4,500 years in
the past. At Fat's page there are links to their sites where everything is neatly described.
Now to 3. This is a serious question. At present reservoir effect is established and taken into account. Special calibration curves were built for other major and
important after atmosphere reservoir - upper ocean. Here also comes a problem of spatial variations. For that the answer is simple. Curves constructed for
Caribbean and Melanesian corals are essentially the same. There are known areas of ocean where deep water upwelling affects radiocarbon dates significantly. But
this is taken into account when dates for such areas are needed. Also see my comments about correction for reservoir effect in FAQ, example with stalagmite and
around.
What about atmosphere? I've already said in FAQ, that for the atmosphere this question was considered and no significant spatial differences were found. I can
again suggest to go to
http://www.radiocarbon.org/Journal/v37n3/druffel.html
http://www.radiocarbon.org/Journal/v40n3/Abstracts/7.html
http://www.radiocarbon.org/Journal/v37n2/Abstracts/395.html
As for this Kauri tree, that authors are so much talking about, I have to comment, that tropical and temperate trees very often do not have any tree-rings (this is why
it is so hard to build any chronology for such regions), or tree-rings are hardly distinguishable. Errors are very possible. Measurements done on the samples of our
Tasmanian Huon pine (well defined annual rings, as all pines) showed very good agreement with northern hemispheric data.
Also, after nuclear tests of the 50's many direct atmospheric measurements were made all around the globe, from northern Norway to South Africa and New
Zealand and South Pole. Except for the very top of the pulse (of a 3-4 years only), right when the most powerful nuclear devices were detonated, there is no
difference between stations. This is an excellent proof of uniformity, in my opinion.
Now it is time for 5. Natural variability of radiocarbon abundance is the cause of those wiggles. And calibration curve was built specifically to account for this effect.
Would there be no variability, there's no need in calibration. But as long as calibration curve constructed, this effect can be considered accounted for. Unfortunately,
the shape of calibration curve can sometimes introduce additional uncertainty.
If your measurement gets within the flat section of the curve, calendar age, corresponding to the measured radiocarbon age can lay within a wider area. It is hard to
explain without figures, go to www.radiocarbon.com and explore the site, you'll find an example there. This can widen radiocarbon method uncertainty for some
periods (but only for some), however, it does not exceed 200 years at most due to that.
Now to the cause of those wiggles. When I got to this section of the paper, it made me laugh. This is where I understood authors were no scientists. No one
self-respecting scientist would go into such groundless speculations, without at least checking the developments on the subject.
A shape wiggles, C shape wiggles, what a bullshit. Negative production rate required? Absolute delirium. Radiocarbon records cannot be deconvolved? Get real
guys. It had been done 20 years ago already. Yours truly had worked a lot on reconstructing radiocarbon production rates and doing cross comparison with 10Be,
the other cosmogenic isotope, produced by cosmic rays in the atmosphere. All wiggles in 10Be and 14C match brilliantly, and the major departure of radiocarbon
curve agrees extremely well with independent geomagnetic field determinations. (I can provide references, if anyone interested, no Net publications though).
The authors had very little (if any) realisation of what the carbon cycle is, how carbon is exchanged and transferred. 14C from the atmosphere is constantly removed
to the ocean. Its lifetime in the ocean is long enough for a significant decay. That's why simple reduction of production rate is enough to explain sharp decreases in
radiocarbon content in the atmosphere.
Actually, there was something about it in the Dergachev's paper on Fat's page.
Now some brief comments on other topics.
Authors accused Libby in using methodology developed for normal distribution to evaluate his data, while in their opinion his measurements form some "flat"
distribution (I wonder what that might mean, haven't heard such a name before). Anyway, they seem to be absolutely ignorant that there are methods of assessing the
fit of measurement series to a particular distribution. I'm pretty sure, Libby as a serious scientist did this test. Those guys so far, offer nothing but words. I can hardly
take this as an argument, more like an insult.
Looking through the list of literature used, it struck me that the absolute majority of publications are from 60's early 70's period. Some rather recent publications (just
a couple) of early 90's are related to dendrochronology only. It seems they thought that science got conserved since the beginning of 80's. Yes, they refer to Long's
publication about the cross-laboratory test. Since then there was another test with much better result (I've said this before) conducted by Polach. Not a single word
about that either.
Yes, authors are good in picking problems. However, they seem to overlook the developments that dealt with those problems and gave solutions (intentionally or
not, I do not know).
But even in this problem-picking they added something completely non-existent, like these heplless speculations about wiggles in calibration curve and their causes.
I could've said much more. But, I'm afraid, even that would be not easy to post.
If any questions remained, you are most welcome.