How accurate is radiocarbon dating?
Everything that has come down to us from paganism is shrouded in a thick fog; it belongs to a span of burden that we cannot measure. We know that it is older than Christianity, but for two years, for two hundred years or for a whole millennium - here we can only guess. Rasmus Nierap, 1806.
Many of us are intimidated by science. Radiocarbon dating as one of the results of the development of nuclear physics is an example of such a phenomenon. This method is essential for different and independent scientific disciplines such as hydrology, geology, atmospheric science and archeology. However, we leave the understanding of the principles of radiocarbon dating to scientists and blindly agree with their conclusions out of respect for the accuracy of their equipment and admiration for their intelligence.
In fact, the principles of radiocarbon dating are strikingly simple and readily available. Moreover, the notion of radiocarbon dating as "an exact science" is a misconception, and in truth, few scientists hold that opinion. The problem is that many disciplines who use radiocarbon dating for chronological purposes do not understand its nature and purpose. Let's take a look at this.
William Frank Libby and his team developed the principles of radiocarbon dating in the 1950s. By 1960, their work was completed, and in December of that year, Libby was nominated for the Nobel Prize in Chemistry. One of the scientists who participated in its nomination noted:
“It has rarely happened that one discovery in the field of chemistry had such an impact on different areas of human knowledge. Very rarely has a single discovery attracted such widespread interest."
Libby discovered that the unstable radioactive isotope of carbon (C14) decays at a predictable rate into stable isotopes of carbon (C12 and C13). All three isotopes occur naturally in the atmosphere in the following proportions; C12 - 98.89%, C13 - 1.11% and C14 - 0.00000000010%.
The stable isotopes of carbon C12 and C13 were formed along with all the other atoms that make up our planet, that is, a very, very long time ago. The C14 isotope is formed in microscopic quantities as a result of the daily, daily bombardment of the solar atmosphere by cosmic rays. When colliding with certain atoms, cosmic rays destroy them, as a result of which the neutrons of these atoms pass into a free state in the earth's atmosphere.
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The C14 isotope is formed when one of these free neutrons fuses with the nucleus of a nitrogen atom. Thus, radiocarbon is a "Frankenstein isotope", an alloy of different chemical elements. Then the C14 atoms, which are formed at a constant rate, undergo oxidation and penetrate into the biosphere during photosynthesis and the natural food chain.
In the organisms of all living things, the ratio of the isotopes C12 and C14 is equal to the atmospheric ratio of these isotopes in their geographic region and is maintained by their metabolic rate. However, after death, organisms cease to accumulate carbon, and the behavior of the C14 isotope becomes interesting from that moment. Libby found that C14 has a half-life of 5568 years; after another 5568 years, half of the remaining atoms of the isotope decays.
Thus, since the initial ratio of C12 to C14 isotopes is a geological constant, the age of a sample can be determined by measuring the amount of residual C14 isotope. For example, if some initial amount of C14 is present in the sample, then the date of death of the organism is determined by two half-lives (5568 + 5568), which corresponds to the age of 10 146 years.
This is the basic principle of radiocarbon dating as an archeological tool. Radiocarbon is absorbed in the biosphere; it stops accumulating with the death of the organism and disintegrates at a certain rate that can be measured.
In other words, the C14 / C12 ratio is gradually decreasing. Thus, we get a "clock" that starts to run from the moment of death of a living being. Obviously, this clock only works for dead bodies that were once living beings. For example, they cannot be used to determine the age of volcanic rocks.
The decay rate of C14 is such that half of this substance is converted back to N14 within 5730 ± 40 years. This is the so-called "half-life". Over two half-lives, that is, 11,460 years, only a quarter of the original amount will remain. Thus, if the C14 / C12 ratio in a sample is a quarter of the ratio in modern living organisms, theoretically this sample is 11,460 years old. It is theoretically impossible to determine the age of objects older than 50,000 years using the radiocarbon method. Therefore, radiocarbon dating cannot show an age of millions of years. If the sample contains C14, this already indicates that its age is less than millions of years.
However, things are not so simple. Firstly, plants absorb less carbon dioxide containing C14. Consequently, they accumulate less than expected and therefore appear older when tested than they actually are. Moreover, different plants metabolize C14 differently, and this should also be corrected for.2
Secondly, the C14 / C12 ratio in the atmosphere was not always constant - for example, it decreased with the onset of the industrial era, when a mass of carbon dioxide depleted in C14 was released due to the burning of huge amounts of fossil fuel. Accordingly, organisms that died during this period appear older in terms of radiocarbon dating. Then there was an increase in C14O2 associated with ground-based nuclear tests in the 1950s, 3 as a result of which the organisms that died during this period began to appear younger than they actually were.
Measurements of the C14 content in objects whose age has been accurately established by historians (for example, grain in tombs with the date of burial) makes it possible to estimate the level of C14 in the atmosphere of that time and, thus, partially "correct the course" of the radiocarbon "clock". Accordingly, radiocarbon dating based on historical data can be very fruitful. However, even with this “historical setting,” archaeologists do not consider radiocarbon dates to be absolute because of frequent anomalies. They rely more on dating methods associated with historical records.
Outside of the historical data, it is not possible to “set” the “clock” C14.
Given all these irrefutable facts, it is extremely strange to see the following statement in the journal Radiocarbon (where the results of radiocarbon studies around the world are published):
“Six reputable laboratories have performed 18 age analyzes of timber from Shelford, Cheshire. Estimates range from 26,200 to 60,000 years (to date), the spread is 34,600 years.
Here's another fact: While the theory of radiocarbon dating sounds compelling, when its principles are applied to laboratory samples, human factors come into play. This leads to errors, sometimes very significant. In addition, laboratory samples are contaminated with background radiation, which alters the C14 residual level that is measured.
As pointed out by Renfrew in 1973 and Taylor in 1986, radiocarbon dating relies on a number of unsubstantiated assumptions made by Libby during the development of his theory. For example, in recent years there has been a lot of discussion about the half-life of C14, supposedly 5568 years. Most scientists nowadays agree that Libby was wrong and that the half-life of C14 is actually about 5,730 years. The 162 year discrepancy takes on a lot of significance when dating millennia-old samples.
But along with the Nobel Prize in Chemistry, Libby gained complete confidence in his new system. Its radiocarbon dating of archaeological specimens from Ancient Egypt has already been dated, as the ancient Egyptians carefully followed their chronology. Unfortunately, radiocarbon analysis gave an too underestimated age, in some cases 800 years less than according to the historical record. But Libby came to a startling conclusion:
"The distribution of data shows that ancient Egyptian historical dates prior to the beginning of the second millennium BC are too overestimated and, perhaps, exceed the true ones by 500 years at the beginning of the third millennium BC."
This is a classic case of scientific conceit and a blind, almost religious belief in the superiority of scientific methods over archaeological ones. Libby was wrong; the radiocarbon method failed him. This problem has now been resolved, but the self-proclaimed reputation of the radiocarbon dating method still exceeds its level of reliability.
My research suggests that there are two major problems with radiocarbon dating, which can still lead to great confusion today. These are (1) contamination of samples and (2) changes in the level of C14 in the atmosphere during geological eras.
Standards for radiocarbon dating. The value of the standard adopted when calculating the radiocarbon age of the sample directly affects the value obtained. Based on the results of a detailed analysis of the published literature, it has been established that several standards were used for radiocarbon dating. The most famous of them: Anderson standard (12.5 dpm / g), Libby standard (15.3 dpm / g) and modern standard (13.56 dpm / g).
Dating the Pharaoh's boat. The wood of the pharaoh's boat Sesostris III was dated by radiocarbon dating based on three standards. When dating wood in 1949, based on the standard (12.5 dpm / g), a radiocarbon age of 3700 ± 50 BP years was obtained. Libby later dated the wood based on the standard (15.3 dpm / g). The radiocarbon age has not changed. In 1955, Libby re-dated the rook wood based on the standard (15.3 dpm / g) and received a radiocarbon age of 3621 ± 180 BP years. When dating the timber of the boat in 1970, the standard (13.56 dpm / g) was used [2]. The radiocarbon age remained almost unchanged and amounted to 3640 BP years. The factual data given by us on the dating of the pharaoh's boat can be checked by the corresponding links to scientific publications.
The price of the issue. Obtaining practically the same radiocarbon age of the wood of the pharaoh's boat: 3621-3700 BP years based on the use of three standards, the values of which differ significantly, is physically impossible. The use of the standard (15.3 dpm / g) automatically gives an increase in the age of the dated sample by 998 years compared to the standard (13.56 dpm / g), and by 1668 years, compared to the standard (12.5 dpm / g) … There are only two ways out of this situation. Recognition that:
- when dating the wood of the boat of the pharaoh Sesostris III, manipulations with the standards were carried out (the wood, contrary to the declarations, was dated based on the same standard);
- Pharaoh Sesostris III's magical boat.
Conclusion
The essence of the considered phenomena, called manipulations, is expressed in one word - falsification.
After death, the C12 content remains constant, while the C14 content decreases
Contamination of samples
Mary Levine explains:
"Contamination is defined as the presence of foreign organic material in a sample that has not been formed with the sample material."
Many photographs from early carbon dating show scientists smoking cigarettes while collecting or processing samples. Not too clever of them! As Renfrew points out, "Drop a pinch of ash on your sample to be analyzed and you get the radiocarbon age of the tobacco your cigarette was made from."
While such methodological incompetence is considered unacceptable these days, archaeological specimens still suffer from pollution. The known types of contamination and how to deal with them are discussed in the article by Taylor (1987). He divides contamination into four main categories: 1) physically removable, 2) soluble in acids, 3) soluble in alkalis, 4) soluble in solvents. All of these contaminants, if not eliminated, greatly affect laboratory determination of the age of the sample.
H. E. Gove, one of the inventors of the Accelerator Mass Spectrometry (AMS) method, radiocarbon dated the Turin Shroud. He came to the conclusion that the fibers of the fabric used to make the shroud date back to 1325.
Although Gove and his colleagues are quite confident in the authenticity of their definition, many, for obvious reasons, consider the age of the Turin Shroud to be much more venerable. Gove and his associates gave a worthy answer to all critics, and if I had to make a choice, I would venture to say that the scientific dating of the Turin Shroud is most likely accurate. But in any case, the hurricane of criticism hitting this particular project shows how expensive a mistake in radiocarbon dating can be and how suspicious some scientists are about this method.
It was argued that the samples may have been contaminated with younger organic carbon; cleaning methods could miss traces of modern pollution. Robert Hedges of Oxford University notes that
"A small systematic error cannot be completely ruled out."
I wonder if he would call the discrepancy in the dating obtained by different laboratories on a sample of wood from Shelford, "a small systematic error"? Doesn't it seem like we are being fooled again with scholarly rhetoric and made to believe in the perfection of existing methods?
Leoncio Garza-Valdes certainly has this opinion in relation to the dating of the Turin Shroud. All ancient tissues are covered with a bioplastic film as a result of the vital activity of bacteria, which, according to Garza-Valdez, confuses the radiocarbon analyzer. In fact, the age of the Turin Shroud may well be 2000 years, since its radiocarbon dating cannot be considered final. Further research is needed. It is interesting to note that Gove (although he disagrees with Garza-Valdez) agrees that such criticism warrants new research.
The cycle of radiocarbon (14C) in the atmosphere, hydrosphere and biosphere of the Earth
C14 level in the earth's atmosphere
According to Libby's “principle of simultaneity,” the C14 level in any given geographic region is constant throughout geological history. This premise was vital for the credibility of radiocarbon dating early in its development. Indeed, to reliably measure the residual level of C14, you need to know how much of this isotope was present in the body at the time of death. But this premise, according to Renfrew, is flawed:
"However, it is now known that the proportional ratio of radiocarbon to conventional C12 did not remain constant over time, and that before 1000 BC the deviations were so great that radiocarbon datings may differ markedly from reality."
Dendrological studies (the study of tree rings) convincingly show that the level of C14 in the earth's atmosphere has been subject to significant fluctuations over the past 8000 years. Hence, Libby chose a false constant and his research was based on erroneous assumptions.
The Colorado pine, found in the southwestern United States, can be thousands of years old. Some trees still alive today were born 4000 years ago. In addition, the logs collected in the places where these trees grew can extend the annals of tree rings for another 4000 years into the past. Other long-lived trees useful for dendrological research are oak and California sequoia.
As you know, a new annual ring grows on the cut of a living tree trunk every year. By counting the tree rings, you can find out the age of the tree. It is logical to assume that the C14 level in the 6,000-year-old annual ring will be similar to the C14 level in the modern atmosphere. But this is not the case.
For example, analysis of tree rings showed that the level of C14 in the earth's atmosphere 6,000 years ago was significantly higher than it is now. Accordingly, radiocarbon samples dating from this age turned out to be noticeably younger than they actually are, based on dendrological analysis. Thanks to the work of Hans Suiss, C14 level correction diagrams were compiled to compensate for its fluctuations in the atmosphere at different time periods. However, this significantly reduced the reliability of radiocarbon dating of samples over 8000 years old. We simply do not have data on the radiocarbon content in the atmosphere prior to this date.
Accelerator mass spectrometer of the University of Arizona (Tucson, Arizona, USA) manufactured by National Electrostatics Corporation: a - schematic, b - control panel and C¯ ion source, c - accelerator tank, d - carbon isotope detector. Photo by J. S. Burra. (Read more about settings here)
"Bad" results?
When the established "age" differs from the expected, researchers hastily find a reason to invalidate the dating result. The widespread availability of this posterior evidence suggests that radiometric dating has serious problems. Woodmorappe cites hundreds of examples of tricks researchers use to explain “inappropriate” age values.
For example, scientists have revised the age of the fossil remains of Australopithecus ramidus.9 Most of the basalt samples closest to the layers in which these fossils were found showed an age of about 23 million years using the argon-argon method. The authors decided that this figure is "too large" based on their ideas about the place of these fossils in the global evolutionary scheme. They looked at basalt farther away from the fossils and, taking 17 of 26 samples, obtained an acceptable maximum age of 4.4 million years. The remaining nine samples showed, again, a much older age, but the experimenters decided that the matter was in the contamination of the rock, and rejected this data. Thus, radiometric dating methods are significantly influenced by the dominant “long ages” worldview in scientific circles.
A similar story is associated with the establishment of the age of the primate skull (this skull is known as the KNM-ER 1470 sample).10, 11 Initially, a result of 212-230 million years was obtained, which, based on the fossils, was considered incorrect (“people at that time still was not”), after which attempts were made to establish the age of volcanic rocks in this region. A few years later, after several different research results were published, they converged on the figure of 2.9 million years (although these studies also included separating the “good” results from the “bad” ones - as was the case with Australopithecus ramidus).
Based on preconceived notions about human evolution, researchers could not come to terms with the idea that the skull of 1470 is "so old." After studying the fossil remains of a pig in Africa, anthropologists readily believed that the skull of 1470 was actually much younger. After the scientific community was confirmed in this opinion, further studies of the rocks further reduced the radiometric age of this skull - to 1.9 million years - and again they found data that "confirm" the next figure. This is such a "game of radiometric dating" …
We are not suggesting that evolutionists have conspired to fit all data to fit the outcome that suits them best. Of course, this is not the case in the norm. The trouble is different: all observation data must correspond to the dominant paradigm in science. This paradigm - or, rather, the belief in millions of years of evolution from molecule to man - is so firmly entrenched in consciousness that no one dares to question it; on the contrary, they speak of the "fact" of evolution. It is under this paradigm that absolutely all observations must fit. As a result, researchers who appear to the public to be "objective and impartial scientists" unconsciously select those observations that are consistent with belief in evolution.
We must not forget that the past is inaccessible for normal experimental research (a series of experiments carried out in the present). Scientists cannot experiment with events that happened before. It is not the age of rocks that is measured - the concentrations of isotopes are measured, and they can be measured with high accuracy. But "age" is determined already taking into account assumptions about the past, which cannot be proved.
We must always remember God's words to Job: "Where were you when I laid the foundations of the earth?" (Job 38: 4).
Those who deal with the unwritten history gather information in the present and thus try to recreate the past. Moreover, the level of requirements for evidence is much lower than in empirical sciences, such as physics, chemistry, molecular biology, physiology, etc.
Williams, an expert on the transformation of radioactive elements in the environment, identified 17 flaws in isotope dating methods (from this dating, three very solid works were published, which made it possible to determine the age of the Earth at approximately 4.6 billion years).12 John Woodmorappe sharply criticizes these dating methods8 and exposes hundreds of myths associated with them. He argues convincingly that the few “good” results left after “bad” data have been filtered out can be easily explained by a lucky coincidence.
What age do you prefer?
Questionnaires offered by radioisotope laboratories usually ask: "How old do you think this sample should be?" But what is this question? There would be no need for it if dating techniques were absolutely reliable and objective. This is likely because laboratories are aware of the prevalence of abnormal results and are therefore trying to figure out how “good” the data they are getting are.
Verification of radiometric dating methods
If radiometric dating methods could truly objectively determine the age of rocks, they would also work in situations where we know the age for sure; moreover, different methods would give consistent results.
Dating methods must show reliable results for objects of known age
There are a number of examples where radiometric dating methods have incorrectly established the age of rocks (this age was precisely known in advance). One such example is the potassium-argon "dating" of five andesitic lava flows from Mount Ngauruho in New Zealand. Although lava was known to have flowed once in 1949, three times in 1954, and again in 1975, the "established ages" ranged from 0.27 to 3.5 Ma.
All the same retrospective method gave rise to the following explanation: when the rock solidified, there was "extra" argon in it due to magma (molten rock). Secular scientific literature provides many examples of how an excess of argon leads to "extra millions of years" when dating rocks of known historical ages.14 The source of excess argon is likely to be the upper part of the Earth's mantle, located just below the earth's crust. This is quite consistent with the theory of the "young earth" - argon had too little time, it simply did not have time to be released. But if an excess of argon has led to such glaring errors in dating rocks of a known age, why should we rely on the same method when dating rocks of unknown age ?!
Other methods - notably the use of isochrones - involve various hypotheses about initial conditions; but scientists are increasingly convinced that even such "reliable" methods also lead to "bad" results. And here again the choice of data is based on the researcher's assumption about the age of a particular breed.
Dr Steve Austin, a geologist, sampled basalt from the lower layers of the Grand Canyon and from lava flows at the edge of the canyon.17 According to evolutionary logic, basalt at the edge of the canyon should be a billion years younger than basalt from the depths. Standard laboratory analysis of isotopes using isochronous rubidium-strontium dating has shown that the relatively recent lava flow is 270 Ma older than basalt from the bowels of the Grand Canyon - which of course is absolutely impossible!
Methodology problems
Libby's original idea was based on the following hypotheses:
14C is formed in the upper atmosphere under the action of cosmic rays, then mixes in the atmosphere, entering into the composition of carbon dioxide. In this case, the percentage of 14C in the atmosphere is constant and does not depend on either time or place, despite the inhomogeneity of the atmosphere itself and the decay of isotopes.
The rate of radioactive decay is constant, measured by a half-life of 5568 years (it is assumed that during this time half of the 14C isotopes are converted to 14N).
Animals and plant organisms build their bodies from carbon dioxide extracted from the atmosphere, while living cells contain the same percentage of the 14C isotope that is in the atmosphere.
Upon the death of an organism, its cells leave the cycle of carbon exchange, but the atoms of the 14C isotope continue to transform into atoms of the stable isotope 12C according to the exponential law of radioactive decay, which makes it possible to calculate the time elapsed since the death of the organism. This time is called "radiocarbon age" (or, for short, "RU-age").
With this theory, as the material accumulated, counterexamples began to appear: the analysis of recently deceased organisms sometimes gives a very ancient age, or, conversely, the sample contains such a huge amount of the isotope that calculations give a negative RU-age. Some obviously ancient objects had a young RU-age (such artifacts were declared late forgeries). As a result, it turned out that RU-age does not always coincide with the true age in cases where the true age can be verified. Such facts lead to reasonable doubts in cases where the RU-method is used for dating organic objects of unknown age, and the RU-dating cannot be verified. Cases of erroneous age determination are explained by the following known shortcomings of Libby's theory (these and other factors are analyzed in the book by M. M. Postnikova "A critical study of the chronology of the ancient world, in 3 volumes", - M.: Kraft + Lean, 2000, in volume 1, pp. 311-318, written in 1978):
1. Variability of the percentage of 14C in the atmosphere. The 14C content depends on the cosmic factor (the intensity of solar radiation) and the terrestrial factor (the entry of "old" carbon into the atmosphere due to the burning and decay of ancient organic matter, the emergence of new sources of radioactivity, fluctuations in the Earth's magnetic field). A change in this parameter by 20% entails an error in the RU-age of almost 2 thousand years.
2. Uniform distribution of 14C in the atmosphere has not been proven. The mixing rate of the atmosphere does not exclude the possibility of significant differences in the 14C content in different geographic regions.
3. The rate of radioactive decay of isotopes can be determined not quite accurately. So, since the time of Libby, the half-life of 14C, according to official reference books, “changed” by a hundred years, that is, by a couple of percent (this corresponds to a change in the RU-age by one and a half hundred years). It is suggested that the value of the half-life significantly (within a few percent) depends on the experiments in which it is determined.
4. Carbon isotopes are not completely equivalent, cell membranes can use them selectively: some absorb 14C, some, on the contrary, avoid it. Since the percentage of 14C is negligible (one 14C atom to 10 billion 12C atoms), even a negligible isotopic selectivity of the cell leads to a large change in the RU-age (a 10% fluctuation leads to an error of about 600 years).
5. Upon the death of an organism, its tissues do not necessarily leave carbon metabolism, participating in the processes of decay and diffusion.
6. The 14C content in the subject may be heterogeneous. Since Libby's time, radiocarbon physicists have learned to very accurately determine the isotope content of a sample; even claim that they are able to count the individual atoms of the isotope. Of course, such a calculation is only possible for a small sample, but in this case the question arises - how accurately does this small sample represent the whole object? How homogeneous is the isotope content in it? After all, errors of a few percent lead to centenary changes in the RU-age.
Summary
Radiocarbon dating is an emerging scientific method. However, at every stage of its development, scientists unconditionally supported its overall reliability and fell silent only after revealing serious errors in estimates or in the method of analysis itself. Errors should not be surprising given the number of variables a scientist must take into account: atmospheric fluctuations, background radiation, bacterial growth, pollution, and human error.
As part of representative archaeological research, radiocarbon dating remains essential; it just needs to be placed in a cultural and historical perspective. Does a scientist have the right to discount contradictory archaeological evidence just because his radiocarbon dating indicates a different age? Is it dangerous. In fact, many Egyptologists have supported Libby's suggestion that the Old Kingdom chronology is wrong, since it was "scientifically proven." In fact, Libby was wrong.
Radiocarbon dating is useful as a supplement to other data, and this is where its strength lies. But until the day comes when all the variables are under control, and all errors are eliminated, radiocarbon dating does not get the final word on the archaeological site.