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Wednesday, February 12, 2014

"45 thousand-year-old fossil wood encased in 45 million-year-old basalt": Conflict Revisited

One point lost by Bill Nye in the recent debate with Ken Ham was the repeated assertion that YEC researchers had dated fossil wood ~1,000 times younger than the basalt in which it was encased. If the assertion holds, then radiometric dating methods to which Bill Nye appeals as evidence for an old Earth are potentially flawed. Unfortunately, Bill Nye did not seem familiar with the claim, reported originally in 1993, despite my prophetic counsel. ;)

Where did these samples come from, and why were they sent to labs for radiometric dating?

In 1993, several samples of charred and petrified wood were collected during construction of a mining ventilation shaft in central Queensland. The wood samples were seemingly well preserved inside the lava flow that encased them. Since the layers of basalt overlay early Cenozoic sediments, the expected age of the lava flow might be a few tens of millions of years. Not convinced by conventional ages of this geologic column, however, local 'young-Earth' geologists paid to have the basalt dated by the K-Ar method and the wood fragments dated by the radiocarbon method. Their reasoning was simple and seemingly innocent: if indeed the Earth is old, then fossilized wood from an ancient lava flow should contain no radioactive carbon (14C) today and will not yield a finite age; if the Earth is young as we claim, however, then detectable 14C should be present in the fossilized wood and the K-Ar age of the basalt cannot be taken seriously.

A full report of this study by Dr. Andrew Snelling of Answers in Genesis is available for download from the Institute for Creation Research [Snelling, 2000. Creation Ex Nihilo Technical Journal, Vol. 14, No. 2, p. 99-122]. The 24-page publication is rather verbose, reading more like a drawn-out lab report than a scientific study, but it contains all the details necessary to assess the feasibility of Dr. Snelling's extraordinary claims.

Wait, if the fossil wood and basalt are both older than 6,000 years, doesn't Ken Ham undermine his own position by citing this study?

I've described at length how apologists at Answers in Genesis use the radiocarbon and Potassium-Argon (K-Ar) methods to argue for a young Earth. In short, they criticize the assumptions behind each dating method. For example, 'model' K-Ar ages assume that all argon was expelled from the sample before molten rock cooled, starting the radiometric clock. If any argon was trapped in the mineral structure, however, then the rock will appear far older than it actually is. We have known for half a century that excess argon may be trapped in lava flows (especially underwater flows under high pressure), so much research in geochronology is devoted to improving the models. Today, more sensitive instrumentation and the aid of computer models allow geochronologists to identify 'excess' argon and calculate ages with far more precision than even a decade ago.

Given the demonstrated robustness of the K-Ar and Ar-Ar methods with these improvements, YEC's have more recently attacked the assumption that radioactive decay occurred at a constant and known rate throughout history. Many of them suggest that during/after the Flood, radioactive decay rates increased substantially, giving the false impression that most rocks are millions or billions of years old. Despite their attempts to confirm this through scientific investigation, however, the claim remains ad hoc and unsubstantiated. On the other hand, continued success using the K-Ar system in pinning down geological events, as well as confirmation from independent dating methods, gives us ample reason to believe that the model assumptions are valid and verified.

The radiocarbon method is far more complicated than is commonly presented, so YEC's have been successful in twisting its results to support their own paradigm. Traditionally, radiocarbon dating assumes that the relative concentration of 14C (the rare radioactive isotope, compared to the stable forms 12C and 13C) does not change with time. When this assumption is used, the results are reported as "radiocarbon years before present". It is important to distinguish between "radiocarbon years" and "calendar years", because we know that the relative concentration of 14C does indeed change over time. The production rate of radioactive carbon in the atmosphere depends on the magnetic field strength, for example, of the Earth and our sun. The YEC can argue, therefore, that prior to the flood, the relative abundance of 14C was much lower than today. If this assertion holds, then plant and animal remains from before the flood should yield dates many times older than their 'actual' age (4,500–6,000 years).

To document the relative abundance of atmospheric 14C over time, geologists use records that can be dated independently of the radiocarbon method. For example, tree-rings and varved lake sediments preserve annual cycles, which may be counted to obtain the actual age of each layer. When tree-rings and varved sediments are dated by the radiocarbon method, the 'radiocarbon age' of each annual band is compared to the real age to construct a calibration curve. This curve removes the assumption in conventional radiocarbon dating that 14C was constant over time.

Stalagmites provide another tool for gaging the history of atmospheric 14C, since these banded records are datable by the U-Th disequilibrium method or, in ideal cases, counting annual bands. By radiocarbon dating calcite along the growth axis of the stalagmite and comparing these ages to U-Th dates, geologists can test and refine the calibration curve (e.g. Vogel and Kronfeld, 1997). These highly corroborated, independent lines of evidence thoroughly disprove the YEC claim that atmospheric 14C increases significantly only after a recent, global flood.

In summary, yes: Ken Ham undermines his own position by citing this study, though he does not mean to.

Why did the fossilized wood give an age of 45,000 years, and how is this possible if the lava flow solidified millions of years ago?

Dr. Snelling submitted two samples of wood to two independent laboratories for radiocarbon dating by Accelerator Mass Spectrometry (AMS). He argues that since the lab obtained 'finite ages' from organic-derived carbon, the fossilized wood cannot possible be tens of millions of years old. He reports the results as follows:

   Sample                             Lab              Age (Radiocarbon Years Before 1950)
"Wood in drill core"             Geochron          >35,620 ± ?
                                         ANSTO               44,700 ± 950
"Other wood"                    Geochron           29,544 ± 759
                                         ANSTO               37,800 ± 3,450

You should notice three features immediately from this table that warrant suspicion of Dr. Snelling's interpretation:

First, all of these ages are close to the practical limit of radiocarbon dating. Even today, radiocarbon ages exceeding ~40,000–50,000 years are commonly considered suspect, because so little radioactive carbon (14C) is being measured that it becomes nearly impossible to distinguish it from contamination or background interference (more on this later). In 1993, this caution was even more applicable, which is why many important geological studies have been updated in recent years from fresh samples analyzed with better equipment.

Second, neither set of dates overlaps within uncertainty, as the sample age differs substantially from one lab to the other. Ages for the "other wood" samples differ by more than 8,000 years, meaning that Geochron measured more than twice the concentration of 14C in the same sample, compared to ANSTO's analysis. If the 14C in these wood samples were derived from a pre-Flood atmosphere, as Ken Ham and Dr. Snelling claim, then all samples should yield the same age. At the very least, each laboratory should be reporting the same concentration of 14C in the duplicate samples. But they don't. From this fact alone, we should be very suspicious that the measured 14C derived from the wood itself. More likely, we might conclude that the 14C concentration differed because variable amounts of atmospheric contamination were incorporated during each lab's preparation methods. These radiocarbon dates do not reflect the age of the fossilized wood, therefore, and do not substantiate Dr. Snelling's claims.

Third, two of the analyses (first and last samples) yielded large uncertainties, which can result when too little 14C is present, or when the source of 14C is not consistent. In the latter case, the source of 14C might be a mixture of contamination sources: atmospheric CO2 or organic acids still bonded to the fossil wood, residual atmosphere inside the sample chamber, or the tiniest of leaks in the vacuum lines. As one who deals daily with mass spectrometers, I would suggest that all three are likely candidates.

Why?

Mass spectrometers do not count atoms of 14C directly, but compare electric intensities produced by ionized particles hitting Faraday cups at the end of a vacuum tube. In theory, particles of the same mass should all follow the same path along the magnetically charged vacuum tube, so the Faraday cups can be positioned to catch each isotope. In reality, particles of the same mass do not hit the same spot consistently, but produce more of a Gaussian distribution. Imagine a fire hose spraying onto a wall: most of the water hits in the center of the stream, but some veers off to the side. If the mass spectrometer measures only 14C (and not 13C bonded to hydrogen, for example), which is distributed evenly through the sample, then the center of the peak is easily found by the instrument. Wider peaks result from low or inconsistent signals, and help us understand why such large uncertainties were associated with two of Dr. Snelling's samples.

Dr. Snelling provides several additional clues that would lead any other investigator to find better samples for dating. First, the basalt flow encasing the wood was only ~21–25 meters below the surface, meaning that it was long exposed to surface waters percolating downward into the rock. These surfaces waters contain not only modern atmosphere, but organic acids that bond tightly to the wood. The wood fragments themselves show evidence of being altered by intruding waters, as Dr. Snelling notes (p. 8): "Permineralization was too advanced" to identify taxonomically important features under the electron microscope. The porous and jointed (fractured) basalt was also altered (p. 14):

"The basalt in the drill core does, in fact, come from the zone of weathering...where percolating oxidizing ground water readily alters minerals and rock chemistry by dissolving and removing various elements."

Yet this basalt was shipped to a lab for K-Ar dating, after which Dr. Snelling criticized the inconsistent and apparently old results. But that is another issue...

The fact that Dr. Snelling's wood samples were long exposed to modern atmospheric and plant material means that at least some of the measured 14C derives from contamination. Despite Dr. Snelling's rant that the laboratories made thorough efforts to remove contaminants and "staunchly defended [the ages] as valid", he admits himself that it is impossible to exclude all contamination. Acid washes cannot contact every single surface of the sample, perfect vacuums are not obtainable in nature, and electrical interference is a constant reality. He may continue to suggest that contamination could not have been large enough to explain finite ages of 30–40,000 years, but he cannot prove this. On the other hand, we can disprove his claim through his failure to replicate the results of his analyses from independent labs.

Dr. Snelling's article mentions that "a δ13C (V-PDB) value of −25.69‰ [is] consistent with terrestrial plant organic carbon...ruling out contamination." Is he right?

Of all the claims made by Dr. Snelling's article, this one is the most obviously and demonstrably false. Forgive my roundabout answer, but this point is important.

In AMS radiocarbon analyses, the relative abundance of 13C (reported as a δ13C value) is routinely measured, because model radiocarbon ages assume that the δ13C value is exactly -25‰. This value represents a reasonable average for the isotopic composition of plant material utilizing C3 photosynthesis, like an oak tree. However, if you were to radiocarbon date a piece of ancient corn (a C4 plant, whose average δ13C value is much higher, around -13‰), you would have to consider that the corn begins with slightly more radioactive carbon (14C) than something like an oak tree of the same age. The difference results from the fact that during photosynthesis, plants preferentially incorporate the lighter isotope(s) of carbon, but the preference is stronger among C3 plants than C4 plants. Since 14C is much heavier than 13C or 12C, it is not incorporated at the same rate as the other isotopes, and this rate varies among photosynthesizers.

If you mix carbon sources with differing isotopic compositions, the δ13C changes proportionately. For example, let's mix 5 grams of wood with a δ13C value of -25‰ and 5 grams of calcite with a δ13C value of 0‰. The resulting δ13C of the mixture is -12.5‰, or a weighted average of the two sources. So what if the 14C in Dr. Snelling's fossil wood samples derived entirely from contamination? Wouldn't the contaminant shift the δ13C value, as he claims?

No. The concentration of 14C in the modern atmosphere is ~10^-12%, or less than one part per trillion. To contaminate a 14C-free sample with enough modern organic carbon to yield a radiocarbon age of ~45,000 years, less than 0.4% of the sample's mass needs to be derived from modern material. If that material is bacteria (δ13C = -27‰ to -33‰) or humic acid (δ13C = -27‰), the δ13C value of the sample will not shift noticeably, because it is so close to the composition of the fossilized wood. But even if the material were atmosphere (δ13C = -7‰) or mineral carbon (δ13C = 0‰, give or take), the δ13C value of the sample would not shift to an extent detectable by the mass spectrometer. Here is the math:

(0.996 * -25.0‰) + (0.004 * 0.0‰) = -24.9‰

Keeping in mind that the uncertainty is close to 0.1‰, and the actual δ13C of trees ranges by 5–6‰...

Conclusion

Ken Ham's appeal to young fossil wood within old basalt may have caught Bill Nye off guard, but his claim remains unsubstantiated. The actual radiocarbon ages of this fossil wood were not reproducible by independent labs within analytical uncertainty, suggesting that contamination and/or background interference was responsible for much of the detected radiocarbon. Recent advances in AMS radiocarbon dating have focused on how to account for the fact that contamination is always introduced during sample preparation and how to correct for various kinds of background interference. Regardless, radiocarbon ages close to the practical limit of the method are always treated with some suspicion.

Radiocarbon dating of independently datable materials (lakes, tree rings, and stalagmites) provide highly corroborated calibration curves of radiocarbon activity over the past ~50,000 years. These studies alone disprove the notion that a recent, global Flood severely impacted concentrations of atmospheric 14C. Combining these records with the inherent uncertainties of the radiocarbon method, which were less resolved in 1993, we might conclude that Ken Ham's proposed dating conflicts are misleading at best.

24 comments:

  1. Good, understandable write up and analysis! Well done!
    Just a couple of minor corrections and comments:
    1) "AMS" stands for acceleratOR (not acceleratED) mass spectrometry. This is because it relies on a particle accelerator to do the measurement. (The accelerator is needed to eliminate interference from such things as molecular species like CH and CH2.)
    2) the detection scheme is usually more complex than you describe. Instead of simple Faraday cups, there is usually a nuclear physics style energy loss detector. But the spirit of your explanation still holds; there is a Gaussian distribution which produces some false counts of 14C.

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    1. Thank you for your feedback, and thanks for the catch regarding AMS; I made the correction in the text. ;)

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  2. Thank you for your thoughtful analysis. It helps to examine the processes and findings more closely. However there are a couple critical questions left unanswered. How many rings did the trees have and how many bands did the stalagmites have when they were first created? Also, don't your explanations prove Ham's point, which was that carbon-dating is generally tricky and unreliable?

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    1. His explanation did not prove that 14C dating is generally tricky and unreliable. It does emphasize the point the sample collection and preservation must be done according to well-established procedures, especially with samples that may be near the detection limit. E.g. if anyone smoked in the room where the samples were kept contamination is inevitable.

      No measurement of any kind gives correct answers in all cases. But the various radiometric dating methods are sufficiently well established that a few failures don't affect their validity. You'd need to find a consistent systemic problem that affects all the measurements. E.g. the RATE group's acknowledgement that Accelerated Nuclear Decay is the only way that a young Earth could fit the radiometric evidence (and their utter failure to come up with a viable hypothesis for and demonstration of such AND).

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    3. >How many rings did the trees have and how many bands did the stalagmites have when they were first created?

      Stalagmites grow from the floors of caves as CaCO3-rich water deposits the supersaturated mineral at contact. They start growing on whatever surface is present.

      The assumption that a stalagmite might exist prior to the commencement of depositional processes is laughable. You might as well take this theory one step further; the world could have been created only yesterday, your memories put in place by god to make you believe that it is (a bit) older.

      You could choose to believe this, but there is no sensible reason to do so, and no evidence to support that belief.

      >Also, don't your explanations prove Ham's point, which was that carbon-dating is generally tricky and unreliable?

      Just because someone with an unscientific agenda chose to willfully misinterpret data does not cast doubt upon the dating system as a whole.

      The above article clearly points out the several mistakes made by Snelling, Ham, et al., to reach the incorrect conclusions that they have reached. The fact that these mistakes are apparent and comprehensible should speak for itself; they made obvious errors. Objective scientists can look at the data and point out the obvious inconsistencies.

      Are there other sources of uncertainty in C14 data? Of course. But, at this point, the technique has been refined to the extent that further advancements will result in refinements probably no larger than a few percent.

      You might as well claim that a gun doesn't work when an experienced user hits within ~1-2 inches of the center of a target's bullseye consistently. Sure, the shooter is not hitting the exact center every time. In fact, s/he'll undoubtedly miss the exact center most of the time. But, unless something goes drastically wrong or an inexperienced idiot picks up the gun, it will hit near the center of the target every time.

      It's a random analogy, but it applies. Radiogenic dating is accurate, when applied correctly. When misused or misinterpreted, the results will vary.

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  3. These are excellent questions, Riley. I'll try to answer them one at a time:

    1) I did not address the scenario in which these trees and decorated caves were created with annual growth bands (an apparent history prior to creation), because Answers in Genesis strongly rejects this view, and my comments were directed to Ken Ham's claim. My answer, however, is the same: none, because they were not present at creation. If you want to suggest, for example, that caves were created with stalagmites already in growth position (full of growth bands), then you must also claim that the fossiliferous sediments in which these caves and trees grew were also created in situ. You would further have to acknowledge that a flood never covered the Earth, because such fragile specimens would not have survived the event, or at least should have recorded it for us. Notwithstanding how this view affects science in general (we should become skeptical of all historical claims, including that the Bible is an ancient written record), we should consider the implications on reading scripture, if we are to force it to read: "God created plants and animals of all kinds, including the trillions of dead specimens locked up in the rocks below your feet."

    These growth bands in stalagmites, trees, coral, lake sediments, ocean sediments, and ice cores record a common history of climatic and ecological changes. The history is not simple to reconstruct, but I am constantly amazed at how well it is preserved in these specimens as I watch the data points accumulate in our lab. Do you think this history is an illusion? Did it never actually happen?

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    1. 2) Radiocarbon dating is by no means a simple process, which is why it has taken thousands of physicists, engineers, chemists, and geologists more than 50 years to develop the method this far. You have to appreciate first the delicacy of this analysis. If we were to analyze the radiocarbon age of your hair, for example, we should find that only ~0.000000000001% of it is comprised of 14C (that's one atom out of every 10 trillion). Isn't it a spectacular feat that despite this, when analyzing varved lake sediments or stalagmites one layer at a time, the radiocarbon age increases, on average, about 1 year at a time?

      You should read more about how the radiocarbon calibration curve is constructed. There are dozens of records for which layers of the same age (estimated by counting) give the same radiocarbon age as others around the Earth. In other words, radiocarbon dating *generally* is very reliable, and not so tricky. It works because generally, the samples we date by radiocarbon really are ~40–50,000 years old or less, whereas the samples submitted by Andrew Snelling were more than 30 million years old. When you intentionally mislead the radiocarbon lab by submitting samples of that age without disclosure, then yes, dating them will be tricky.

      There is a scientific journal called Radiocarbon, devoted entirely to improvements to the method and new applications thereof. It is filled with thousands of examples where radiocarbon has proven trustworthy, in that it yields for us the same geological age as other radiometric methods. It also highlights the kind of samples that will be tricky to date, because it is more difficult to rule out contamination. Petrified wood, ash, and coal, are all such samples.

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  4. Thanks for this post - I tried to get to the bottom off this Ham claim (via Snelling) at the debate, as Ham mentioned it again on Facebook this week after Nye made a Facebook page about the planned Ark Encounter. But I only got as far as finding this 1997 AiG article: http://www.answersingenesis.org/articles/cm/v20/n1/dating
    Ham of course claimed on his Facebook that this was 'evidence' yet at the debate Nye 'willingly' ignored it (I assume he really meant to write 'wilfully').
    Last night or the night before I also flagged the Ham-Snelling claim on Bill Nye's Facebook - suggesting they search to see whether ANY peer-reviewed science paper has reported this claim anomaly.

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  5. [With typos corrected.]

    Thanks for this post - I tried to get to the bottom of this Ham claim (via Snelling) at the debate, as Ham mentioned it again on Facebook this week after Nye made a Facebook post about the planned Ark Encounter. But I only got as far as finding this 1997 AiG article: http://www.answersingenesis.org/articles/cm/v20/n1/dating
    Ham of course claimed on his Facebook that this was 'evidence' yet at the debate Nye 'willingly' ignored it (I assume he really meant to write 'wilfully').
    Last night or the night before I also flagged the Ham-Snelling claim on Bill Nye's Facebook - suggesting they search to see whether ANY peer-reviewed science paper has reported this claimed anomaly.

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  6. Good article! I was thinking of tossing something together myself but no need now.

    I would have emphasized the contamination more. Snelling's only comment was:

    "The possibility of contamination is also an important consideration which was raised with the laboratories’ staff. For example, recent microbial and fungal activity long after the wood was buried, including spores and dust in the laboratories, might have contaminated the fossilized wood with various amounts of radiocarbon to produce these different 14C “ages.” However, the responses were unhesitatingly unanimous that there would be no such contamination problem (Krueger, 1996; Lawson, 1996). ..."

    and he goes on to explain why. But he completely ignores the much more likely contamination from collection and storage by unqualified (but no doubt well-meaning and honest" people.

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    1. Thanks, Jon. You're right to emphasize this point, thanks for adding in the quote from Snelling's article. I only hinted at this in noting that one lab measured significantly more 14C than the other. To expand here, this may suggest that various amounts of contamination were incorporated during the respective lab's preparation/storage methods. There is certainly more awareness today of samples' sensitivity to contamination than in 1993..!

      Also, you mentioned smoking in the lab as a potential contaminant. In case anyone took that half seriously, I'll add that I've witnessed this in the last year...in shock, but still, it happened. ;)

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    2. Well, I was thinking more of smoking at collection (which was fairly common for archaeologists in the early days of 14C) or during storage in Australia. But the point stands either way.

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  7. You are on fire! Nice to have you back online.

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    1. Thank you. :) I missed writing too much..!

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  8. My problem with is not so much Ham's and Snellings misinformation but to ask how you can have any organic matter such as trees survive being encased in the molten magma of the pre Basaltic state.

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    1. Hard to believe, yes, but it is possible. Large portions of the wood they found had been turned to ash/charcoal, so only a small portion remained as wood with identifiable features. That portion had been permineralized by infiltrating waters long after the basalt cooled and eventually cracked to allow groundwater inside. Keep in mind that despite the high temperatures, the oxygen is consumed very rapidly as the edge of the wood is converted to ash (once encased, no more oxygen enters the system), so the entire sample will not burn completely. Secondly, the high moisture content of the wood serves as something of a thermal barrier (like a radiator in a hot engine) and prevents at least part of the wood sample from 'cooking' beyond recognition. The lava in contact with the wood and its moisture solidifies rapidly to form an additional thermal barrier. Check out this video for a more vivid example:

      Lava meets coke can:
      http://www.youtube.com/watch?v=GaSjwAu3yrI

      About 30 seconds in, note how the lava crusts around the hammer, but does not melt the hammer, handle, or glove.
      http://www.youtube.com/watch?v=NIWlA7ndAlw

      Lava flow casting a forest in real time:
      http://www.youtube.com/watch?v=06ZQTlbs8Yw

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  9. May I suggest that you read and study this paper given at a conference held at the National Research Council of Italy Feb, 23, 2009 and published under the editorship of the VP of this Italian government research agency. The title is: "RECENT C-14 DATING OF FOSSILS INCLUDING DINOSAUR BONE COLLAGEN - Are the results a confirmation of rapid formation of the geologic column as modern sedimentology studies have predicted?" and the link is http://www.sciencevsevolution.org/Holzschuh.htm These data are repeatable and consistent at four different AMS labs and between bone fractions.

    An updated PP report was given at the Biogeoscience section of the AOGS-AGU Assembly of 2000 scientists on August 12 of 2012 in Singapore entitled: A COMPARISON OF δ13C & pmC VALUES for TEN CRETACEOUS-JURASSIC DINOSAUR BONES from TEXAS to ALASKA USA, CHINA AND EUROPE - The abstract can be sent upon request. You are a geologist and therefore have access to museum storage areas in Moscow. So if in doubt of these discoveries I suggest that you gather up some bone fragments and C-14 date the fragments at the Russian Academy of Sciences in Moscow and see if you can reproduce our ages in the range of 22,000 to 40,000 years. One caution: If you test for C-14 in trabicular bone [inner material] stay away from cracked area as all carvbon material will probably have been leached out as we learned the hard way. Run a carbon and collagen analysis first. If you date the outer cortical bone [very hard] then you can date total organic or just the CaCO3 of the bioapatite even if near cracks, If the Russians do not have AMS, as I've been lead to believe then you'll need much larger samples [150 to 500 grams] or send them to a German AMS lab. Sincerely, Hugh Miller, Research chemist and one of the coauthors of both of the above papers


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    2. To "Date the Fossils Not the Rocks": Sorry, but I am not impressed with your paper. It presents a laundry list of previous radiocarbon dates with very little analysis. Worse, it rejects and ignores the analysis and explanations of the original authors, who are the experts on the samples.

      Do any of the authors of this paper have experience with radiocarbon AMS analysis? If so, why don't they know what the initials AMS stand for?!? If not, what experience do they have in other ultra-sensitive analytical techniques?

      Radiocarbon AMS is an EXTREMELY sensitive technique, and samples are very easy to contaminate inadvertently. Yes, collagen is very stable, and separated collagen is a good material for dating. But this collagen can easily be contaminated with modern carbon after separation. Bone is a tricky material to date, and there are only a few experts in the world who can do it well. (See Wood et al, Radiocarbon 52:2 pp 600-611: https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/3695)

      Why does your paper (http://www.sciencevsevolution.org/Holzschuh.htm) claim that sample UGAMS-01935ff is from a "Hadrosaur femur", whereas Cherkinsky's paper (Radiocarbon 51:2 pp647-655) say this was "burnt bison bone" from Montana? Which one is it?

      As you both(?) note, the collagen and the bio-apatite give consistent dates, and this suggests that the sample was not contaminated. However, this would also be consistent with a high background due to the chemical processing that was used, or due to the instrument background itself. Why should we believe that you are not simply measuring your system background? To ask it another way, what is the oldest bone date that has been obtained on the UGA AMS system using Cherkinsky's cleaning procedure?

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    3. Mr. Miller,

      I took the time to read the material you cited, but I see no strong case being made. Beside the fact that the papers are poorly written (as if in a hurry) and rife with appeals to authority (evidence of a weak case), I see many inconsistencies in the data, leading me to believe that you have only proven radiocarbon an ineffective method in dating dinosaur collagen (which seems not to have been consistently extracted, given the scatter of δ13C values).

      Yes, I am a geologist, but I am not about to spend $1,000+ flying to Moscow to subsample bone fragments (to which they would not give me access anyways) at $500+ per sample just to see if I can replicate your spurious results. Even if I had this money, I would spend it on my own research first (I actually need some AMS analyses, but lack the funding).

      There are a million reasons not to conclude that these dinosaur bones are <50,000 years old, and though it's a hard break for you I'm sure, the Singapore conference was right to remove your abstract.

      Regards,

      Jon

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  11. Do you guys realize that you cannot carbon date something that doesn't have carbon in it, such as dinosaur bones or petrified wood. They lack carbon SOOOOO you can not carbon date them... geeze.

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    1. Yes, everyone realizes this. The petrified wood samples I referred to were not completely permineralized, however, so the residual charcoal (presumably) provided the bulk of the carbon for their analysis. Nobody is claiming to have dated the permineralized (silicate) portion of the petrified wood. Regarding the dinosaur bones, while bone structure was completely replaced, Mr. Miller proposed that trace amounts of collagen (the part that's routinely 14C-dated in vertebrate bones) could be extracted and dated. In theory, collagen (or at least the carbon deriving from it) could be trapped in the mineral structure and preserved for a very long time. For these bones, however, there was no extractable collagen, which explains the scatter of the data. There was carbon in the dinosaur bones (all dino bones will contain at least some carbon), but the source of the carbon was neither bone nor collagen. These dates reflected contaminants.

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