What radionuclide is used for radiocarbon dating. Criticism of radiocarbon dating method

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Radiocarbon dating, part 1

Radiocarbon dating, part 2

Radioisotope dating: are the fundamentals of the technique reliable?

Shroud of Turin - radiocarbon dating

Antikythera Mechanism: Fact and Fiction

Subtitles

In this video I would like to focus, firstly, on how carbon-14 appears and how it penetrates into all living things. And then, either in this video or in future videos, we'll talk about how it's used for dating, that is, how it can be used to discover that this bone is 12,000 years old, or that this person died 18,000 years ago - anything. Let's draw the Earth. This is the surface of the Earth. More precisely, only a small part of it. Then comes the Earth's atmosphere. I'll paint it yellow. This is where we have the atmosphere. Let's sign it. And 78% - the most common element in our atmosphere is nitrogen. It's 78% nitrogen. I'll write it down: "nitrogen". Its symbol is N. It has 7 protons and 7 neutrons. So atomic mass is approximately 14. And the most common isotope of nitrogen... We discuss the concept of isotope in a chemistry video. In an isotope, protons determine what element it is. But this number can change depending on the available number of neutrons. Variants of a given element that differ in this way are called isotopes. I think of these as versions of a single element. In any case, we have an atmosphere, as well as so-called cosmic radiation emanating from our sun, but this is not actually radiation. These are cosmic particles. You can think of them as single protons, which is the same as hydrogen nuclei. They can also be alpha particles, which is the same thing as helium nuclei. Sometimes there are also electrons. They arrive, then collide with the components of our atmosphere and, in fact, form neutrons. So, neutrons are produced. Let's denote a neutron with a small letter n, then 1 is its mass number. We don't write anything because there are no protons here. Unlike nitrogen, where there were 7 protons. So it is, strictly speaking, not an element. A subatomic particle. So, neutrons are formed. And every now and then... Let's face it, this doesn't seem like a typical reaction. But every now and then one of these neutrons collides in a certain way with a nitrogen-14 atom. It knocks out one of the nitrogen protons and, in fact, itself takes its place. I'll explain now. It knocks out one of the protons. Now, instead of seven protons, we get 6. But this number 14 will not change to 13, because a replacement has occurred. So there will be 14 left here. But now, since there are only 6 protons, this, by definition, is no longer nitrogen. Now it's carbon. And the proton that was knocked out will be emitted. I'll paint this in a different color. This is a plus. A proton emitted into space... You can call it hydrogen 1. Somehow it can attract an electron. If it doesn't gain an electron, it will simply be a hydrogen ion, a positive ion anyway, or a hydrogen nucleus. This process is not a typical phenomenon, but it happens from time to time - this is how carbon-14 is formed. So here's carbon-14. Essentially, you can think of it as nitrogen-14, where one of the protons is replaced by a neutron. The interesting thing is that it is constantly formed in our atmosphere, not in huge quantities, but in noticeable quantities. I'll write this down. Constant formation. Fine. Now... I want you to be clear. Let's look at the periodic table. By definition, carbon has 6 protons, but the typical, most common isotope of carbon is carbon-12. Carbon-12 is the most common. Most of the carbon in our body is carbon-12. But what's interesting is that it produces a small amount of carbon-14, and then that carbon-14 can combine with oxygen to form carbon dioxide. The carbon dioxide is then absorbed into the atmosphere and ocean. It can be taken over by plants. When people talk about carbon sequestration, they are actually talking about energy use. sunlight to capture carbon gas and convert it into organic tissue. So carbon-14 is constantly being produced. It's in the oceans, it's in the air. Mixes with the whole atmosphere. Let's write: oceans, air. And then it gets into the plants. Plants are, in fact, composed of this fixed carbon, which has been captured in gaseous form and transferred, so to speak, into solid form, into living tissue. For example, this is what wood is made of. Carbon is built into plants and then ends up in those who eat the plants. It could be us. Why is this interesting? I have already explained the mechanism, even if carbon-12 is the most common isotope, part of our body accumulates carbon-14 during our lifetime. What's interesting is that you can only get this carbon-14 while you're alive and while you're eating food. Because once you die and you're buried underground, carbon-14 can no longer become part of your tissues because you no longer eat anything that contains carbon-14. And once you die, you no longer receive carbon-14 replenishment. And the carbon-14 that you had at the time of death will decay through β-decay - we have already studied this - back into nitrogen-14. That is, the process is going backwards. So it decays to nitrogen-14, and β decay releases an electron and an anti-neutrino. I won't go into details now. Essentially, that's what's going on here. One of the neutrons turns into a proton, and during the reaction it emits this. Why is this interesting? As I said, as long as you live, carbon-14 is coming in. Carbon-14 is constantly decaying. But once you're gone and you're no longer consuming plants, or breathing in the atmosphere, if you're a plant yourself, taking up carbon from the air - which is what plants are all about... When a plant dies, it's no longer consuming carbon dioxide from the atmosphere or incorporating it in the fabric. The carbon-14 in this fabric is “frozen.” Then it disintegrates at a certain speed. It can then be used to determine how long ago the creature died. The rate at which this happens, the rate at which carbon-14 decays until half of it disappears or disintegrates by half is about 5,730 years. This is called the half-life. We talk about this in other videos. This is called the half-life. I want you to understand this. It is unknown which half has disappeared. This is a probabilistic concept. You can only assume that all the carbon-14 on the left will decay, and all the carbon-14 on the right will not decay within those 5,730 years. Essentially, this means that any given carbon-14 atom has a 50 percent chance of decaying to nitrogen-14 within 5,730 years. That is, in 5,730 years, approximately half of them will decay. Why is it important? If you know that all living things have a certain amount of carbon-14 in their tissues as part of their constituent substances, and then you find some bone... Let's say you find a bone during an archaeological dig. You will say that this bone has half the carbon-14 of the living things around you. It would be perfectly reasonable to assume that this bone must be 5,730 years old. It's even better if you dig even deeper and find another bone. Maybe a couple of feet deeper. And you will find that it contains 1/4 of the carbon-14 that would be found in a living thing. Then how old is he? If it is only 1/4 carbon-14, it has gone through 2 half-lives. After one half-life it would have 1/2 carbon left. Then, after the second half-life, half of that will also turn into nitrogen-14. So 2 half-lives have occurred here, giving 2 times 5,730 years. What would be the conclusion about the age of the item? Plus or minus 11,460 years. Subtitles by the Amara.org community

Physical foundations

In 2015, scientists from Imperial College London calculated that the continued use of hydrocarbons would negate radiocarbon dating.

Currently, several methods are used to determine the age of archaeological finds, the most reliable of which is considered to be radiocarbon dating. However, even this most reliable method has huge errors. Thanks to the analysis of the data obtained, scientists realized that the rate of radioactive decay is not constant, as previously thought, since it is influenced by many external factors. This means that the “atomic clock” gets lost depending on external conditions.

Here are just some examples of dating with the “most accurate” method. Carbon-14 (14 C) dating showed that the newly killed seal died 1,300 years ago; the shells of living snails were 27,000 years old; the age of a shell of a living mollusk is 2,300 years old, etc. In the Belt cave (Iran), the underlying layer is dated to be approximately 6,000 years old, and the overlying one is 8,500 years old. That is, the reverse sequence of layers is obtained, which, of course, is impossible. And there are many similar examples.

How can we explain this magnitude of error in the most accurate method? The fact is that this analysis is carried out by determining the ratio of radioactive carbon-14 to stable carbon in the sample. It is believed that from the moment the vital activity of organic material ceases, “new” carbon-14 does not enter it, and the existing one gradually disintegrates at a constant rate, while stable carbon, of course, remains unchanged. However, under different conditions, carbon from the external environment (from everything nearby that contains carbon: volcanic phenomena, the action of fire and even high temperature, from the soil or from the atmosphere) can penetrate into the sample under study. And then the picture changes dramatically!

Rice. The principle of radiocarbon dating method

In addition, no one can know for sure how the level of carbon-14 in the atmosphere has changed over different periods. But scientists definitely know that it has changed, and significantly. Dendrological studies (analysis of tree rings) show that the level of carbon-14 in the earth's atmosphere has changed greatly over the past 4 - 5 thousand years (the oldest trees have this ring age; it is not possible to calculate the exact age, because annual rings change over time they simply merge, and in some cases several growth rings can form in one year). But no one knows what happened before; this is a matter of guesswork. Moreover, we cannot be sure that the carbon-14 in ancient tree rings corresponds to the carbon-14 in the atmosphere at the time the ring grew. Indeed, over the following years, this part of the tree was in direct contact with neighboring layers of the trunk, with nutrients, sunlight, air and other external factors, which could not but affect the carbon content.

Thus, radiocarbon analysis can be trusted with great reserve and used only as one of the confirming factors of the age of the find, but not as the main and determining one.

In the works of critics of the radiocarbon method one can find the following quote: “Six reputable laboratories carried out 18 age analyzes on wood from Shelford in Cheshire. Estimates range from 26,000 to 60,000 years, with a range of 34,000 years.”1.

Also, many dates obtained using radiocarbon dating do not match the chronology established by historians and archaeologists based on documents and artifacts.

When discussing the radiocarbon dating method, one cannot help but pay attention to a few more points. Claims of significant age for ancient finds based on measurements of the amount of carbon-14 in them can be explained using the Bible. The fact is that before the flood, which, according to biblical calculations, occurred approximately 4.5 thousand years ago, the content of carbon-14 in the Earth's atmosphere should have been minimal. According to the Holy Scriptures, before the Flood, one of the layers of the atmosphere over our planet was a protective dome of water 2. The water shield protected the Earth from radioactive carbon-14 and harmful cosmic radiation. Therefore, as one would expect, in antediluvian samples the content of carbon-14 is extremely low, which is perceived by material scientists as a consequence of its decay, and therefore they talk about significant time periods.

In addition, carbon dating is not even theoretically designed to determine ages greater than 50,000 years. Scientists themselves openly declare this. Therefore, materialists cannot explain in any way why coal, oil and diamonds also contain carbon-14. After all, according to scientific data, carbon-14 has a short half-life (5,730 years) and simply cannot exist in samples dating back hundreds of thousands of years, let alone many millions, much less billions of years. However, carbon-14 is present in all layers, which confirms the young age of the Earth.

1 Hancock G. Traces of the Gods. M., 2006.

Radiocarbon dating has changed our understanding of the last 50,000 years. Professor Willard Libby first demonstrated it in 1949, for which he was later awarded the Nobel Prize.

Dating method

The essence radiocarbon dating consists of comparing three different isotopes of carbon. Isotopes of a particular element have the same number of protons in the nucleus, but different number neutrons. This means that although they are very chemically similar, they have different masses.

The total mass of the isotope is indicated by a numerical index. While the lighter isotopes 12C and 13C are stable, the heaviest isotope 14C (radiocarbon) is radioactive. Its core is so large that it is unstable.

Over time, 14C—the basis of radiocarbon dating—breaks down into nitrogen, 14N. Most carbon-14 is created in the upper atmosphere, where neutrons produced by cosmic rays react with 14N atoms.

It is then oxidized into 14CO 2, enters the atmosphere and mixes with 12CO 2 and 13CO 2. Carbon dioxide is used by plants during photosynthesis and from there passes through the food chain. Therefore, every plant and animal in this chain (including humans) will have an equal amount of 14C compared to 12C in the atmosphere (14C:12C ratio).

Limitations of the method

When living things die, tissue is no longer replaced and radioactive decay of 14C becomes apparent. After 55 thousand years, 14C decays so much that its residues can no longer be measured.

What is radiocarbon dating? Radioactive decay can be used as a "clock" because it is independent of physical (eg temperature) and chemical (eg water content) conditions. In 5730 years, half of the 14C contained in the sample decays.

Therefore, if the ratio of 14C:12C at the time of death and the ratio today are known, then we can calculate how much time has passed. Unfortunately, identifying them is not so easy.

Radiocarbon dating: uncertainty

The amount of 14C in the atmosphere, and therefore in plants and animals, was not always constant. For example, it varies depending on how many cosmic rays reach the Earth. It depends on solar activity and magnetic field of our planet.

Fortunately, it is possible to measure these variations in samples dated by other methods. It is possible to calculate tree rings and changes in their radiocarbon content. From this data a "calibration curve" can be constructed.

Currently, work is underway to expand and improve it. In 2008, only radiocarbon dates up to 26,000 years could be calibrated. Today the curve has been extended to 50,000 years.

What can be measured?

Not all materials can be dated using this method. Most, if not all, organic compounds allow radiocarbon dating. Some inorganic substances, such as the aragonite component of the shells, can also be dated because carbon-14 was used in the formation of the mineral.

Materials that have been dated since the method's inception include charcoal, wood, twigs, seeds, bones, shells, leather, peat, silt, soil, hair, pottery, pollen, wall paintings, coral, blood remains, fabrics, paper, parchment, resin and water.

Radiocarbon dating of a metal is not possible unless it contains carbon-14. The exception is iron products, in the manufacture of which coal is used.

Double count

Because of this complication, radiocarbon dates are presented in two ways. Uncalibrated measurements are reported in number of years prior to 1950 (BP). Calibrated dates are also presented as BC. BC, and after, and also using the calBP unit (calibrated up to the present, until 1950). This is the "best estimate" of the actual age of the sample, but it is necessary to be able to go back to old data and calibrate it as new research continually updates the calibration curve.

Quantity and quality

The second difficulty is the extremely low prevalence of 14C. Only 0.0000000001% of the carbon in the modern atmosphere is 14C, making it incredibly difficult to measure and extremely sensitive to pollution.

In the early years, radiocarbon dating of decay products required huge samples (for example, half a human femur). Many laboratories now use an accelerator mass spectrometer (AMS), which can detect and measure the presence of various isotopes, as well as count the number of individual carbon-14 atoms.

This method requires less than 1 g of bone tissue, but few countries can afford more than one or two AMS, which cost more than $500 thousand. For example, Australia has only 2 such instruments that are capable of radiocarbon dating, and they are unattainable for much of the developing world.

Cleanliness is the key to precision

In addition, the samples must be thoroughly cleaned of carbon contaminants from the adhesive and soil. This is especially important for very old materials. If 1% of an element in a 50,000-year-old sample comes from a modern contaminant, it will be dated as 40,000 years old.

For this reason, researchers are constantly developing new methods for effectively purifying materials. They can have a significant impact on the result given by radiocarbon dating. The accuracy of the method has increased significantly with the development of a new cleaning method with activated carbon ABOx-SC. This made it possible, for example, to delay the date of the arrival of the first people in Australia by more than 10 thousand years.

Radiocarbon dating: criticism

The method proving that much more than the 10 thousand years mentioned in the Bible has passed since the origin of the Earth has been repeatedly criticized by creationists. For example, they argue that after 50,000 years there should be no carbon-14 left in the samples, but coal, oil and natural gas, believed to be millions of years old, contain measurable amounts of this isotope, which is confirmed by carbon dating. The measurement error in this case is greater than the background radiation, which cannot be eliminated in the laboratory. That is, a sample that does not contain a single atom of radioactive carbon will show a date of 50 thousand years. However, this fact does not cast doubt on the dating of the objects, and certainly does not indicate that oil, coal and natural gas are younger than this age.

Creationists also note some oddities in radiocarbon dating. For example, dating of freshwater mollusks determined their age to be greater than 2000 years, which, in their opinion, discredits this method. In fact, it has been established that shellfish receive most carbon from limestone and humus, the 14C content of which is very low, since these minerals are very old and do not have access to air carbon. The radiocarbon dating, the accuracy of which in this case can be questioned, is otherwise consistent with reality. Wood, for example, does not have this problem, because plants get carbon directly from the air, which contains a full dose of 14C.

Another argument against the method is the fact that trees are capable of forming more than one ring in one year. This is true, but more often it happens that they do not form growth rings at all. The bristlecone pine, which is the basis for most measurements, has 5% fewer rings than its actual age.

Setting the date

Radiocarbon dating is not only a method, but also exciting discoveries about our past and present. The method allowed archaeologists to place finds in chronological order without the need for written records or coins.

In the 19th and early 20th centuries, incredibly patient and careful archaeologists linked pottery and stone tools from different geographic areas by looking for similarities in shape and pattern. Then, using the idea that object styles evolved and became more complex over time, they could place them in order.

Thus, large domed tombs (known as tholos) in Greece were considered to be the predecessors of similar structures on the Scottish island of Maeshowe. This supported the idea that the classical civilizations of Greece and Rome were at the center of all innovation.

However, radiocarbon dating revealed that the Scottish tombs were thousands of years older than the Greek ones. The northern barbarians were capable of designing complex structures similar to the classical ones.

Other notable projects included assigning the Shroud of Turin to the medieval period, dating the Dead Sea Scrolls to the time of Christ, and the somewhat controversial periodization of the Chauvet Cave paintings at 38,000 calBP (about 32,000 BP), thousands of years earlier than expected.

Radiocarbon dating has also been used to determine the timing of the extinction of mammoths and has contributed to the debate over whether modern people and Neanderthals or not.

The 14C isotope is used not only to determine age. Radiocarbon dating allows us to study ocean circulation and trace the movement of drugs throughout the body, but this is a topic for another article.

Radiocarbon method for determining absolute age

Quaternary deposits

The essence of the radiocarbon method is as follows: cosmic rays bombard nitrogen nuclei (N 14) with neutrons. In doing so, they knock protons out of nitrogen. As a result, radioactive carbon C14 is formed from nitrogen (a heavy isotope of carbon with an atomic weight of 14 is created). It goes according to this formula:

N14+ n ® C14 + P

n - neutron

P - proton

Radioactive carbon C14 (radiocarbon) is capable of decay. Decay leads to the transition of radioactive carbon C14 into ordinary nitrogen N14. The decay of C14 occurs by ejection of a particle (electron - e) from the nucleus. It goes according to this formula:

The half-life (“life”) of radioactive carbon C14 is T=5568 +-30 years. The ratio of radioactive carbon (C14) to ordinary carbon (C12) in atmospheric carbon dioxide is constant.

This C14/C12 ratio is also observed in living organisms (animals and plants). This happens because they continuously absorb carbon from the atmosphere. In this case, plants assimilate it directly from the air (photosynthesis), and animals absorb carbon by eating plants.

After the death of a plant or animal, the metabolic process in dead organic matter stops. As a result, radioactive carbon ceases to enter living organisms (it can only enter during the life of the organism during the metabolic period). From this moment (after the death of an animal or plant), the decay of radioactive carbon begins. As a result, its amount gradually decreases both in buried plants and in buried animals. If we take the content of radioactive carbon (C14) in a living organism as 100%, then over time it will decrease as follows (for example):

Date of death of C14

Having determined the amount of C14 in any paleontological object in this way, one can judge the number of years that have passed since the death of animals and plants.

Based on radioactive carbon, the age of sediments is determined quite accurately, no more than 30 thousand years, i.e. the age of Holocene and partially Upper Pleistocene deposits. The age of more ancient (middle and lower Pleistocene) deposits is determined by ion and other radioactive methods. This is due to the fact that when sediments are more than 30 thousand years old, very little radioactive carbon remains in the organic matter and its content cannot be accurately determined. However, using a more complex method, it is possible to determine the age of deposits up to 40-45 thousand years.

The value of the radiocarbon method lies in the fact that with its help it is possible to establish the age of not only well-preserved organic remains, but also of their fragments, which are not paleontologically determinable.

To determine the age of sediments, organic matter taken from these sediments is subjected to certain chemical treatments. Then the decay pulses of the radioactive substance are counted. This is done using a Geiger counter.

The carbon of carbonates is not suitable for dating using the radiocarbon method. It is eliminated by dissolving the sample in hydrochloric acid. Hence, calcareous shell samples are usually unsuitable for this method. Animal bones and wood contaminated with carbonates must be treated with hydrochloric acid to remove the carbonates.

The most suitable research objects for this method are:

1. Charcoal - (sample weight 30-90 g);

2. Dry wood and other plant residues - (60 g);

3. Dry peat, skin, hair, hooves, claws - (150-300 g);

4. Animal horns - (500-2200 g).

When taking samples, they are guided by the following provisions:

1) the sample weight in the field is taken at least twice as large as that required for analysis (see above).

2) Samples are taken from freshly cleared outcrops. They are then packaged in aluminum or tin foil or tin boxes.

Radiocarbon dating is used to study the age of continental sediments. Ionic method used to determine the rate of sediment accumulation in modern oceans.

Radiocarbon dating is:

Radiocarbon dating Changes in atmospheric concentrations of radiocarbon 14C caused by nuclear testing. Blue shows natural concentration

Radiocarbon analysis- a physical method of dating biological remains, objects and materials of biological origin by measuring the content of the radioactive isotope 14C in the material relative to stable isotopes of carbon. Proposed by Willard Libby in 1946 (Nobel Prize in Chemistry, 1960).

Physical foundations

Carbon, which is one of the main components of biological organisms, is present in the earth's atmosphere in the form of stable isotopes 12C and 13C and radioactive 14C. The 14C isotope is constantly formed in the atmosphere under the influence of radiation (mainly cosmic rays, but also radiation from terrestrial sources). The ratio of radioactive and stable carbon isotopes in the atmosphere and in the biosphere at the same time in the same place is the same, since all living organisms constantly participate in carbon metabolism and receive carbon from the environment, and isotopes, due to their chemical indistinguishability, participate in biochemical processes in almost the same way. In a living organism, the specific activity of 14C is approximately 0.3 decays per second per gram of carbon, which corresponds to an isotopic content of 14C of about 10−10%.

With the death of the body, carbon metabolism stops. After this, stable isotopes are preserved, and radioactive (14C) undergoes beta decay with a half-life of 5568 ± 30 years (according to new updated data - 5730 ± 40 years), as a result, its content in the remains gradually decreases. Knowing the initial ratio of isotope content in the body and measuring their current ratio in biological material, it is possible to determine how much carbon-14 has decayed and, thus, establish the time that has passed since the death of the organism.

Application

To determine the age, carbon is isolated from a fragment of the sample under study (by burning the fragment), radioactivity is measured for the released carbon, based on this, the isotope ratio is determined, which shows the age of the sample. The carbon sample used to measure activity is usually introduced into a gas that fills a proportional counter or into a liquid scintillator. Recently, for very low 14C contents and/or very small sample masses (several mg), accelerator mass spectrometry has been used to directly determine the 14C content. Age limit sample that can be determined by radiocarbon dating is about 60,000 years, i.e. about 10 half-lives of 14C. During this time, the 14C content decreases by about 1000 times (about 1 decay per hour per gram of carbon).

Measuring the age of an object using the radiocarbon method is possible only when the ratio of isotopes in the sample has not been disturbed during its existence, that is, the sample has not been contaminated with carbon-containing materials of later or earlier origin, radioactive substances and has not been exposed to strong sources of radiation. Determining the age of such contaminated samples can lead to huge errors. For example, a case is described when a test determination of grass picked on the day of analysis gave an age of the order of millions of years, due to the fact that the grass was picked on a lawn near a road with constant strong movement and turned out to be heavily contaminated with “fossil” carbon from exhaust gases (burnt petroleum products). Over the decades since the development of the method, extensive experience has been accumulated in identifying contaminants and in cleaning samples from them. The error of the method is currently believed to range from seventy to three hundred years.

One of the most famous cases of using the radiocarbon method is the study of fragments of the Shroud of Turin ( Christian shrine, allegedly containing traces of the body of the crucified Christ), carried out in 1988, simultaneously in several laboratories using a blind method. Radiocarbon analysis made it possible to date the shroud to the period of the 11th-13th centuries.

Calibration

Libby's initial assumptions on which the idea of ​​the method was based were that the ratio of carbon isotopes in the atmosphere does not change in time and space, and the content of isotopes in living organisms exactly corresponds to the current state of the atmosphere. It is now firmly established that all these assumptions can only be approximately accepted. The content of the 14C isotope depends on the radiation situation, which changes in time due to fluctuations in the level of cosmic rays and solar activity, and in space, due to the unequal distribution of radioactive substances on the Earth's surface and events associated with radioactive materials (for example, at present Radioactive materials that were formed and dispersed during atmospheric nuclear weapons tests in the mid-20th century still contribute to the formation of the 14C isotope). IN last decades Due to the combustion of fossil fuels, in which 14C is practically absent, the atmospheric content of this isotope decreases. Thus, accepting a certain isotope ratio as constant can generate significant errors (on the order of millennia). In addition, research has shown that some processes in living organisms lead to excessive accumulation of the radioactive isotope of carbon, which disrupts the natural ratio of isotopes. Understanding of the processes associated with carbon metabolism in nature and the influence of these processes on the isotope ratio in biological objects was not achieved immediately.

As a result, radiocarbon dates made 30-40 years ago often turned out to be very inaccurate. In particular, a test of the method carried out at that time on living trees several thousand years old showed significant deviations for wood samples over 1000 years old.

Currently, for the correct application of the method, careful calibration has been carried out, taking into account changes in the ratio of isotopes for different eras and geographic regions, as well as taking into account the specifics of the accumulation of radioactive isotopes in living beings and plants. To calibrate the method, the determination of isotope ratios is used for objects whose absolute dating is known. One source of calibration data is dendrochronology. A comparison was also made of determining the age of samples using the radiocarbon method with the results of other isotope dating methods. The standard curve used to convert the measured radiocarbon age of a sample to an absolute age is given here: .

It can be stated that in its modern form over the historical interval (from tens of years to 60-70 thousand years in the past), the radiocarbon method can be considered a fairly reliable and qualitatively calibrated independent method for dating objects of biological origin.

Criticism of the method

Despite the fact that radiocarbon dating has long been included in scientific practice and is quite widely used, there is also criticism of this method, calling into question both individual cases of its application and the theoretical foundations of the method as a whole. As a rule, the radiocarbon method is criticized by supporters of creationism, " New chronology"and other theories not recognized by the scientific community. The main objections to radiocarbon dating are given in the article Criticism of natural scientific methods in Fomenko’s “New Chronology”. Often criticism of radiocarbon dating is based on the state of the methodology in the 1960s, when the method was not yet reliably calibrated.

see also

• Optical dating
• Thermoluminescence dating

Links

• V. Levchenko. Radiocarbon and absolute chronology: notes on the topic.
• V.A. Dergachev. Radiocarbon chronometer.

Radioisotope dating

Radioisotope or radiometric dating- a method for determining the age of various objects that contain any radioactive isotope. It is based on determining what fraction of this isotope has decayed during the lifetime of the sample. From this value, knowing the half-life of a given isotope, the age of the sample can be calculated.

Radioisotope dating is widely used in geology, paleontology, archeology and other sciences. This is the source of almost all absolute dating of various events in the history of the Earth. Before its appearance, only relative dating was possible - binding to certain geological eras, periods, eras, etc., the duration of which was unknown.

Different radioisotope dating methods use different isotopes of different elements. Since they differ greatly in chemical properties (and therefore in their content in various geological and biological materials and in their behavior in geochemical cycles), as well as in their half-lives, they different methods The scope of applicability differs. Each method is only applicable to certain materials and a certain age range. The most famous methods of radioisotope dating are radiocarbon, potassium-argon (modification - argon-argon), potassium-calcium, uranium-lead and thorium-lead methods. Also, to determine the geological age of rocks, helium (based on the accumulation of helium-4 from alpha-active natural isotopes), rubidium-strontium, samarium-neodymium, rhenium-osmium, lutetium-hafnium methods are widely used. In addition, non-equilibrium dating methods are used, based on the disturbance of isotopic equilibrium in natural radioactive series, in particular ionium, ionium-protactinium, uranium isotope methods and the lead-210 method. There are also methods based on the accumulation of changes in physical properties mineral under irradiation: track dating method and thermoluminescent method.

Story

The idea of ​​radioisotope dating was proposed by Ernest Rutherford in 1904, 8 years after the discovery of radioactivity by Henri Becquerel. At the same time, he made the first attempt to determine the age of the mineral based on the content of uranium and helium [Comm. 1]. Just 2 years later, in 1907, Bertram Boltwood, a radiochemist at Yale University, published the first uranium-lead dating of a number of uranium ore samples and obtained age values ​​from 410 to 2200 million years. The result was great importance: He showed that the age of the Earth is many times greater than the 20-40 million years estimated ten years earlier by William Thomson based on the rate of cooling of the planet. However, at that time it was not known about the formation of part of lead as a result of the decay of thorium and even about the existence of isotopes, and therefore Boltwood’s estimates were usually overestimated by tens of percent, sometimes almost twice.

In subsequent years, there was intensive development of nuclear physics and improvement of technology, thanks to which by the middle of the 20th century good accuracy of radioisotope dating was achieved. This was especially helped by the invention of the mass spectrometer. In 1949, Willard Libby developed radiocarbon dating and demonstrated its usefulness on wood samples of known age (ranging from 1400 to 4600 years), for which he received the 1960 Nobel Prize in Chemistry.

Physical Basics

The amount of any radioactive isotope decreases over time according to an exponential law (law of radioactive decay):

N (t) N 0 = e − λ t (\displaystyle (\frac (N(t))(N_(0)))=e^(-\lambda t)) ,

N 0 (\displaystyle N_(0)) - the number of atoms at the initial moment, N (t) (\displaystyle N(t)) - the number of atoms after time t (\displaystyle t) , λ (\displaystyle \lambda ) - decay constant.

Thus, each isotope has a strictly defined half-life - the time during which its amount is halved. The half-life T 1 / 2 (\displaystyle T_(1/2)) is related to the decay constant as follows:

T 1 / 2 = ln ⁡ 2 λ (\displaystyle T_(1/2)=(\frac (\ln 2)(\lambda )))

Then we can express the ratio N (t) N 0 (\displaystyle (\frac (N(t))(N_(0)))) in terms of the half-life:

N (t) N 0 = 2 − t / T 1 / 2 (\displaystyle (\frac (N(t))(N_(0)))=2^(-t/T_(1/2)))

Based on how much of the radioisotope decayed over a period of time, we can calculate this time:

T = − T 1 / 2 log 2 ⁡ N (t) N 0 (\displaystyle t=-T_(1/2)\log _(2)(\frac (N(t))(N_(0))) )

The half-life does not depend on temperature, pressure, chemical environment, or intensity of electromagnetic fields. The only known exception concerns those isotopes that decay by electron capture: they have a dependence of the decay rate on the electron density in the region of the nucleus. These include, for example, beryllium-7, strontium-85 and zirconium-89. For such radioisotopes, the decay rate depends on the degree of ionization of the atom; there is also a weak dependence on pressure and temperature. This is not a significant problem for radioisotope dating.

Sources of difficulties

The main sources of difficulty for radioisotope dating are the exchange of matter between the object under study and the environment that may have occurred after the object's formation, and the uncertainty of the initial isotopic and elemental composition. If at the time the object was formed it already contained a certain amount of the daughter isotope, the calculated age may be overestimated, and if the daughter isotope subsequently left the object, it may be underestimated. For the radiocarbon method, it is important that the ratio of carbon isotopes at the initial moment is not disturbed, since the content of the decay product - 14N - cannot be known (it is no different from ordinary nitrogen), and the age can only be determined based on measurements of the undecayed fraction of the parent isotope. Thus, it is necessary to study the history of the object under study as accurately as possible for possible exchange of matter with the environment and possible features of the isotopic composition.

Isochron method

The isochron method helps solve problems associated with the addition or loss of a parent or daughter isotope. It works regardless of the initial amount of the daughter isotope and allows you to determine whether there has been an exchange of matter with the environment in the history of the object.

This method is based on comparing data on different samples from the same geological object, which are obviously the same age, but differ in elemental composition (hence, the content of the parent radionuclide). The isotopic composition of each element at the initial moment should be the same in all samples. Also, these samples must contain, along with the daughter isotope, some other isotope of the same element. The samples can represent either different minerals from the same piece of rock or different parts of the same geological body.

Then for each sample the following is executed:

D 0 + Δ M E 0 = Δ M M 0 − Δ M (M 0 − Δ M E 0) + D 0 E 0 (\displaystyle (D_(0)+\Delta (M) \over E_(0))=(\ Delta (M) \over M_(0)-\Delta (M))\left((M_(0)-\Delta (M) \over E_(0))\right)+(D_(0) \over E_ (0))) ,

D 0 (\displaystyle D_(0)) - concentration of the daughter isotope at the initial moment, E 0 (\displaystyle E_(0)) - concentration of the non-radiogenic isotope of the same element (does not change), M 0 (\displaystyle M_(0)) is the concentration of the parent isotope at the initial moment, Δ M (\displaystyle \Delta (M)) is the amount of the parent isotope that decayed during time t (\displaystyle t) (at the time of measurements).

It is easy to verify the validity of this relationship by making a reduction on the right side.

The concentration of the daughter isotope at the time of measurements will be D t = D 0 + Δ M (\displaystyle D_(t)=D_(0)+\Delta (M)), and the concentration of the parent isotope M t = M 0 − Δ M (\displaystyle M_ (t)=M_(0)-\Delta (M)) . Then:

D t E 0 = Δ M M 0 − Δ M (M t E 0) + D 0 E 0 (\displaystyle (D_(t) \over E_(0))=(\Delta (M) \over M_(0) -\Delta (M))\left((M_(t) \over E_(0))\right)+(D_(0) \over E_(0)))

The ratios D t E 0 (\displaystyle D_(t) \over E_(0)) and M t E 0 (\displaystyle (M_(t) \over E_(0))) can be measured. After this, a graph is constructed where these values ​​are plotted along the ordinates and abscissas, respectively.

If in the history of the samples there was no exchange of matter with the environment, then the corresponding points on this graph fall on a straight line, because the coefficient Δ M M 0 − Δ M (\displaystyle (\Delta (M) \over M_(0)-\ Delta (M))) and the term D 0 E 0 (\displaystyle (D_(0) \over E_(0))) are the same for all samples (and these samples differ only in the initial content of the parent isotope). This line is called an isochrone. The greater the slope of the isochrone, the greater the age of the object under study. If there was an exchange of matter in the history of the object, the points do not lie on the same straight line and this shows that in in this case age determination is unreliable.

The isochron method is used in various radioisotope dating methods, such as rubidium-strontium, samarium-neodymium and uranium-lead.

Closing temperature

If a mineral whose crystal lattice does not hold a daughter nuclide is heated strongly enough, this nuclide will diffuse outward. Thus, the “radioisotope clock” is reset: the time that has passed since this moment is obtained as a result of radioisotope dating. When cooling below a certain temperature, the diffusion of a given nuclide stops: the mineral becomes a closed system in relation to this nuclide. The temperature at which this occurs is called the closing temperature.

Closing temperatures vary greatly between different minerals and the different elements considered. For example, biotite begins to noticeably lose argon when heated to 280±40 °C, and zircon loses lead at temperatures above 950-1000 °C.

Radioisotope dating methods

Various radioisotope methods are used that are suitable for different materials, different age intervals and have different accuracy.

Uranium-lead method

Main article: Uranium-lead method Microscopic zircon crystal dated by the uranium-lead method. The laser ablation hole is visible

The uranium-lead method is one of the oldest and most well-developed methods of radioisotope dating and, when performed well, the most reliable method for samples hundreds of millions of years old. Allows you to get an accuracy of 0.1% and even better. It is possible to date both samples close in age to the Earth and samples younger than a million years. Greater reliability and accuracy are achieved through the use of two isotopes of uranium, the decay chains of which end in different isotopes of lead, as well as due to some properties of zircon, a mineral commonly used for uranium-lead dating.

The following transformations are used:

238U → 206Pb with a half-life of 4.47 billion years (radium series - see Radioactive series), 235U → 207Pb with a half-life of 0.704 billion years (actinium series).

Sometimes, in addition to them, the decay of thorium-232 is used ( uranium-thorium-lead method):

232Th → 208Pb with a half-life of 14.0 billion years (thorium series).

All these transformations occur in many stages, but intermediate nuclides decay much faster than the parent nuclides.

Most often, zircon (ZrSiO 4) is used for dating by the uranium-lead method; in some cases - monazite, titanite, baddeleyite; less commonly, many other materials, including apatite, calcite, aragonite, opal, and rocks consisting of a mixture of different minerals. Zircon has great strength, resistance to chemical influences, a high closure temperature and is widespread in igneous rocks. Uranium is easily incorporated into its crystal lattice and lead is not, so all lead in zircon can usually be considered radiogenic. If necessary, the amount of non-radiogenic lead can be calculated from the amount of lead-204, which is not formed during the decay of uranium isotopes.

The use of two isotopes of uranium, decaying to different isotopes of lead, makes it possible to determine the age of an object even if it loses some of the lead (for example, due to metamorphism). In addition, the age of this metamorphic event can be determined.

Lead-lead method

Main article: Lead-lead method

The lead-lead method is usually used to determine the age of samples consisting of a mixture of minerals (its advantage in such cases over the uranium-lead method is due to the high mobility of uranium). This method is well suited for dating meteorites, as well as terrestrial rocks that have experienced recent uranium loss. It is based on the measurement of three isotopes of lead: 206Pb (formed by the decay of 238U), 207Pb (formed by the decay of 235U) and 204Pb (non-radiogenic).

The change in the ratio of lead isotope concentrations over time is derived from the following equations:

[ 207 P b ] t = [ 207 P b ] 0 + [ 235 U ] 0 (e λ 235 t − 1) (\displaystyle (\left[^(207)\mathrm (Pb) \right]_(t) )=(\left[^(207)\mathrm (Pb) \right]_(0))+(\left[^(235)\mathrm (U) \right]_(0))(\left(( e^(\lambda _(235)t)-1)\right))) [ 206 P b ] t = [ 206 P b ] 0 + [ 238 U ] 0 (e λ 238 t − 1) (\displaystyle ( \left[^(206)\mathrm (Pb) \right]_(t))=(\left[^(206)\mathrm (Pb) \right]_(0))+(\left[^(238 )\mathrm (U) \right]_(0))(\left((e^(\lambda _(238)t)-1)\right))) ,

where index t (\displaystyle t) means the concentration of the isotope at the time of measurement, and index 0 (\displaystyle 0) - at the initial moment.

It is convenient to use not the concentrations themselves, but their ratios to the concentration of the non-radiogenic isotope 204Pb.
Omitting the square brackets:

(207 P b 204 P b) t = (207 P b 204 P b) 0 + (235 U 204 P b) (e λ 235 t − 1) (\displaystyle (\left((\frac (^(207) \mathrm (Pb) )(^(204)\mathrm (Pb) ))\right)_(t))=(\left((\frac (^(207)\mathrm (Pb) )(^(204) \mathrm (Pb) ))\right)_(0))+(\left((\frac (^(235)\mathrm (U) )(^(204)\mathrm (Pb) ))\right)) (\left((e^(\lambda _(235)t)-1)\right))) (206 P b 204 P b) t = (206 P b 204 P b) 0 + (238 U 204 P b ) (e λ 238 t − 1) (\displaystyle (\left((\frac (^(206)\mathrm (Pb) )(^(204)\mathrm (Pb) ))\right)_(t)) =(\left((\frac (^(206)\mathrm (Pb) )(^(204)\mathrm (Pb) ))\right)_(0))+(\left((\frac (^( 238)\mathrm (U) )(^(204)\mathrm (Pb) ))\right))(\left((e^(\lambda _(238)t)-1)\right)))

Dividing the first of these equations by the second and taking into account that the modern ratio of concentrations of parent uranium isotopes 238U/235U is almost the same for all geological objects (the accepted value is 137.88), [Comm. 2] we get:

(207 P b 204 P b) t − (207 P b 204 P b) 0 (206 P b 204 P b) t − (206 P b 204 P b) 0 = (1 137 , 88) (e λ 235 t − 1 e λ 238 t − 1) (\displaystyle (\frac (\left((\frac (^(207)\mathrm (Pb) )(^(204)\mathrm (Pb) ))\right)_( t)-\left((\frac (^(207)\mathrm (Pb) )(^(204)\mathrm (Pb) ))\right)_(0))(\left((\frac (^( 206)\mathrm (Pb) )(^(204)\mathrm (Pb) ))\right)_(t)-\left((\frac (^(206)\mathrm (Pb) )(^(204) \mathrm (Pb) ))\right)_(0)))=(\left((\frac (1)(137.88))\right))(\left((\frac (e^(\lambda _(235)t)-1)(e^(\lambda _(238)t)-1))\right)))

Next, a graph is constructed with the ratios 207Pb/204Pb and 206Pb/204Pb along the axes. On this graph, points corresponding to samples with different initial U/Pb ratios will line up along a straight line (isochrone), the slope of which shows the age of the sample.

The time of planet formation was determined using the lead-lead method solar system(that is, the age of the Earth). This was first done by Claire Cameron Patterson in 1956 from studies of different types of meteorites. Because they are fragments of planetesimals that have undergone gravitational differentiation, different meteorites have different meaning U/Pb, which allows you to construct an isochrone. It turned out that this isochron also contains a point representing the average ratio of lead isotopes for the Earth. The current age of the Earth is 4.54 ± 0.05 billion years.

Potassium-argon method

Main article: Potassium-argon method

This method uses the decay of the 40K isotope, which is 0.012% of natural potassium. It decays mainly in two ways [Comm. 3]:

• β−-decay (probability 89.28(13)%, partial half-life [Comm. 4] 1.398 billion years):

19 40 K → 20 40 C a + e − + ν ¯ e ; (\displaystyle \mathrm (()_(19)^(40)K) \rightarrow \mathrm (()_(20)^(40)Ca) +e^(-)+(\bar (\nu )) _(e)\,;)

• electron capture (probability 10.72(13)%, partial half-life 11.64 billion years):

19 40 K + e − → 18 40 A r + ν e . (\displaystyle \mathrm (()_(19)^(40)K) +e^(-)\rightarrow \mathrm (()_(18)^(40)Ar) +(\nu )_(e) \,.)

The half-life of 40K, taking into account both decay paths, is 1.248(3) billion years. This makes it possible to date both samples with an age equal to the age of the Earth, and samples with an age of hundreds and sometimes tens of thousands of years.

Potassium is the 7th most abundant element in the earth's crust, and many igneous and sedimentary rocks contain large amounts of this element. The fraction of the 40K isotope in it is constant with good accuracy. Potassium-argon dating uses a variety of micas, solidified lava, feldspars, clay minerals, and many other minerals and rocks. Solidified lava is also suitable for paleomagnetic studies. Therefore, the potassium-argon method (more precisely, its version - the argon-argon method) is the main method for calibrating the geomagnetic polarity scale.

The main decay product of potassium-40 - 40Ca - is no different from ordinary (non-radiogenic) calcium-40, which is usually abundant in the studied rocks. Therefore, the content of another daughter isotope, 40Ar, is usually analyzed. Since argon is an inert gas, it easily evaporates from rocks when heated to several hundred degrees. Accordingly, potassium-argon dating shows the time of the last heating of the sample to such temperatures.

The main problem for potassium-argon dating, as for other radioisotope methods, is the exchange of matter with the environment and the difficulty of determining the initial composition of the sample. It is important that the sample does not initially contain argon, and then does not lose it and is not contaminated by atmospheric argon. A correction can be made for this contamination based on the fact that in atmospheric argon there is, in addition to 40Ar, another isotope (36Ar), but due to the small amount of it (1/295 of all argon), the accuracy of this correction is low.

There is an improved version of the potassium-argon method - the 40Ar/39Ar method ( argon-argon method). Using this method, instead of the 40K content, the 39Ar content is determined, which is formed from 39K during artificial neutron irradiation. The amount of 40K can be unambiguously determined from the amount of 39K due to the constancy of the isotopic composition of potassium. The advantage of this method is due to the fact that the chemical properties of 39Ar and 40Ar are identical, so that the content of these isotopes can be determined from the same sample using the same method. But every argon-argon dating requires calibration using a sample of known age irradiated with the same neutron flux.

Comparison of potassium-argon dates with uranium-lead dates shows that potassium-argon dates are usually about 1% smaller. This is probably due to the inaccuracy of the accepted value for the half-life of potassium-40.

Rubidium-strontium method

Main article: Rubidium-strontium method

The principle of the method is based on the β− decay of the 87Rb isotope and its transformation into the stable 87Sr isotope:

37 87 R b → 38 87 S r + β − + ν ¯ e + Q ; (\displaystyle \mathrm (()_(37)^(87)Rb) \rightarrow \mathrm (()_(38)^(87)Sr) +(\beta )^(-)+(\bar (\ nu ))_(e)+Q\,;)

where ν e- electron antineutrino, Q- decay energy. The half-life of rubidium-87 is 49.7(3) billion years, its natural isotopic abundance is 27.83(2)%. The abundance of rubidium in rock minerals is determined, first of all, by the proximity of the ionic radii Rb+ ( r= 0.148 nm) to K+ ions ( r= 0.133 nm). This allows the Rb ion to replace the K ion in all the most important rock-forming minerals.

The abundance of strontium is determined by the ability of the Sr2+ ion ( r= 0.113 nm) replace the Ca2+ ion ( r= 0.101 nm), in calcium-containing minerals (mainly in plagioclase and apatite), as well as the possibility of its inclusion in the lattice of potassium feldspars in place of the K+ ion. The accumulation of strontium-87 in the mineral occurs according to the law

(87 S r 86 S r) t = (87 S r 86 S r) 0 + (87 R b 86 S r) t ⋅ (e λ t − 1) , (\displaystyle \left((\frac (^( 87)\mathrm (Sr) )(^(86)\mathrm (Sr) ))\right)_(t)=\left((\frac (^(87)\mathrm (Sr) )(^(86) \mathrm (Sr) ))\right)_(0)+\left((\frac (^(87)\mathrm (Rb) )(^(86)\mathrm (Sr) ))\right)_(t )\cdot \left(e^(\lambda t)-1\right),)

where is the index t, as always, refers to the modern ratios of isotope concentrations in the mineral, and 0 refers to the initial ratios. Solving this equation for age t allows you to write the basic equation of geochronology in relation to the Rb-Sr method:

T = 1 λ ln ⁡ ((87 S r 86 S r) t − (87 S r 86 S r) 0 (87 R b 86 S r) t + 1) , (\displaystyle t=(\frac (1) (\lambda ))\ln \left((\frac (\left((\frac (^(87)\mathrm (Sr) )(^(86)\mathrm (Sr) ))\right)_(t) -\left((\frac (^(87)\mathrm (Sr) )(^(86)\mathrm (Sr) ))\right)_(0))(\left((\frac (^(87) \mathrm (Rb) )(^(86)\mathrm (Sr) ))\right)_(t)))+1\right),)

The isotopic abundance of radiogenic (87Sr) and non-radiogenic (86Sr) strontium isotopes used in the method is 7.00(1)% and 9.86(1)%, respectively.

Samarium-neodymium method

Main article: Samarium-neodymium method

Samarium and neodymium are rare earth elements. They are less mobile than alkali and alkaline earth elements such as K, Rb, Sr etc. during hydrothermal alteration and chemical weathering and metamorphism. Therefore, the samarium-neodymium method provides more reliable dating of the age of rocks than the rubidium-strontium method. The proposal to use the Sm-Nd method in geochronology was first made by G. Lugmair (1947). He showed that the 143Nd/144Nd ratio is an indicator of changes in the relative abundance of 143Nd due to the decay of 147Sm. In the development and implementation of the Sm-Nd method in geological practice and processing of the resulting data huge contribution contributed by US researchers DePaolo and Wasserburg. Samarium has 7 natural isotopes (see Isotopes of samarium), but only two of them (147Sm and 148Sm[Comm. 5]) are radioactive. 147Sm turns, emitting an alpha particle, into 143Nd:

62 147 R b → 60 143 N d + α + Q ; (\displaystyle \mathrm (()_(62)^(147)Rb) \rightarrow \mathrm (()_(60)^(143)Nd) +(\alpha )+Q\,;)

The half-life of 147Sm is very long - 106.6(7) billion years. The samarium-neodymium method is best used for calculating the age of basic and ultrabasic rocks, including metamorphic ones.

Rhenium-osmium method

Main article: Rhenium-osmium method

The method is based on the beta decay of rhenium-187 (half-life 43.3(7) billion years, natural isotopic abundance η = 62.60(2)%) into osmium-187 (η = 1.96(2)%). The method is used for dating iron-nickel meteorites (rhenium, as a siderophile element, tends to be concentrated in them) and molybdenite deposits (molybdenite MoS 2 in the earth's crust is a rhenium concentrator mineral, like the minerals tantalum and niobium). Osmium is associated with iridium and is found almost exclusively in ultramafic rocks. Isochrone equation for the Re-Os method:

(187 O s 186 O s) t = (187 O s 186 O s) 0 + (187 R e 186 O s) t ⋅ (e λ 187 t − 1) . (\displaystyle \left((\frac (^(187)\mathrm (Os) )(^(186)\mathrm (Os) ))\right)_(t)=\left((\frac (^(187 )\mathrm (Os) )(^(186)\mathrm (Os) ))\right)_(0)+\left((\frac (^(187)\mathrm (Re) )(^(186)\ mathrm (Os))\right)_(t)\cdot \left(e^(\lambda _(187)t)-1\right).)

Lutetium-hafnium method

Main article: Lutetium-hafnium method

The method is based on the beta decay of lutetium-176 (half-life 36.84(18) billion years, natural isotopic abundance η = 2.599(13)%) into hafnium-176 (η = 5.26(7)%). Hafnium and lutetium have significantly different geochemical behavior. Heavy lanthanide minerals such as fergusonite, xenotime, etc., as well as apatite, orthite, and sphene are suitable for the method. Hafnium is a chemical analogue of zirconium and is concentrated in zircons, so zircons are not suitable for this method. Isochrone equation for the lutetium-hafnium method:

(176 H f 177 H f) t = (176 H f 177 H f) 0 + (176 L u 177 H f) t ⋅ (e λ 176 t − 1) . (\displaystyle \left((\frac (^(176)\mathrm (Hf) )(^(177)\mathrm (Hf) ))\right)_(t)=\left((\frac (^(176 )\mathrm (Hf) )(^(177)\mathrm (Hf) ))\right)_(0)+\left((\frac (^(176)\mathrm (Lu) )(^(177)\ mathrm (Hf))\right)_(t)\cdot \left(e^(\lambda _(176)t)-1\right).)

Radiocarbon method

Main article: Radiocarbon dating

The method is based on the decay of carbon-14 and is most often used for objects of biological origin. It allows you to determine the time that has passed since the death of a biological object and the cessation of carbon exchange with the atmospheric reservoir. The ratio of carbon-14 to stable carbon (14C/12C ~ 10−10%) in the atmosphere and in the tissues of animals and plants that are in equilibrium exchange with it is determined by the flux of fast neutrons in the upper atmosphere. Neutrons created by cosmic rays react with atmospheric nitrogen-14 nuclei according to the reaction n + 7 14 N → 6 14 C + p , (\displaystyle n+\mathrm (^(14)_(7)N) \rightarrow \mathrm (^ (14)_(6)C) +p,) producing an average of about 7.5 kg of carbon-14 per year. The half-life of 14C is 5700 ± 30 years; existing methods make it possible to determine radiocarbon concentrations in biological objects at a level approximately 1000 times lower than the equilibrium atmospheric concentration, that is, with an age of up to 10 half-lives of 14C (about 60 thousand years).

On the accuracy of the radiocarbon dating method

Everything that has come down to us from paganism is shrouded in thick fog; it belongs to that interval of burden which we cannot measure. We know that it is older than Christianity, but by two years, two hundred years or a whole millennium - here we can only guess. Rasmus Nierup, 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 has important implications for different and independent scientific disciplines such as hydrology, geology, atmospheric science and archaeology. However, we leave the understanding of the principles of radiocarbon dating to the scientific experts and blindly accept their conclusions out of respect for the accuracy of their equipment and admiration for their intelligence.

In fact, the principles of radiocarbon dating are amazingly simple and easily accessible. Moreover, the idea of ​​carbon dating as an “exact science” is misleading, and in truth, few scientists hold this opinion. The problem is that representatives of many disciplines who use radiocarbon dating for chronological purposes do not understand its nature and purpose. Let's look into this.

Principles of Radiocarbon Dating
William Frank Libby and members of his team developed the principles of radiocarbon dating in the 1950s. By 1960, their work was complete, and in December of that year, Libby was nominated for the Nobel Prize in Chemistry. One of the scientists involved in his nomination noted:

“Rarely has it happened that one discovery in the field of chemistry has had such an impact on different fields 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%.

Stable carbon isotopes 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 bombardment of the solar atmosphere by cosmic rays. When cosmic rays collide with certain atoms, they destroy them, as a result of which the neutrons of these atoms become free in the earth's atmosphere.

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 C14 atoms, which are formed at a constant rate, undergo oxidation and penetrate into the biosphere through the process of photosynthesis and the natural food chain.

In the organisms of all living beings, the ratio of C12 and C14 isotopes is equal to the atmospheric ratio of these isotopes in their geographical region and is maintained by their metabolic rate. However, after death, organisms stop accumulating carbon, and the behavior of the C14 isotope from this point on becomes interesting. Libby found that the half-life of C14 was 5568 years; After another 5568 years, half of the remaining atoms of the isotope decay.

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 an age of 10,146 years.

This is the basic principle of radiocarbon dating as an archaeological tool. Radiocarbon is absorbed into the biosphere; it stops accumulating with the death of the organism and decays at a certain rate that can be measured.

In other words, the C14/C12 ratio gradually decreases. Thus, we get a “clock” that begins to tick from the moment of death of a living being. Apparently this clock only works on 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”. After 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 one-quarter that of modern living organisms, the sample is theoretically 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 ages of millions of years. If the sample contains C14, this already indicates that its age less million years.

However, everything is not so simple. Firstly, plants absorb carbon dioxide containing C14 worse. Consequently, they accumulate less of it than expected and therefore appear older than they actually are when tested. Moreover, different plants absorb C14 differently, and allowances should be made for this too.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 the burning of huge quantities of fossil fuels released a mass of carbon dioxide depleted in C14. Accordingly, organisms that died during this period appear older under radiocarbon dating. Then there was an increase in C14O 2 associated with above-ground nuclear testing in the 1950s,3 causing organisms that died during this period to appear younger than they actually were.

Measurements of C14 content in objects whose age has been precisely established by historians (for example, grain in tombs with an indication of the date of burial) make it possible to estimate the level of C14 in the atmosphere at that time and, thus, partially “correct the clock” of the radiocarbon “clock”. Accordingly, radiocarbon dating, carried out taking into account historical data, can give very fruitful results. However, even with this “historical setting,” archaeologists do not consider radiocarbon dates to be absolute, due to frequent anomalies. They rely more on dating methods associated with historical records.

Outside of historical data, “tuning” the C14 “clock” is not possible

In the laboratory
Given all these irrefutable facts, it is extremely strange to see the following statement in the journal Radiocarbon (which publishes the results of radiocarbon studies around the world):

“Six reputable laboratories carried out 18 age analyzes on wood from Shelford in Cheshire. Estimates range from 26,200 to 60,000 years (before the present), with a range of 34,600 years."

Here's another fact: Although the theory of radiocarbon dating sounds convincing, when its principles are applied to laboratory samples, human factors come into play. This leads to errors, sometimes very significant ones. In addition, laboratory samples are contaminated by background radiation, altering the residual level of C14 that is measured.

As Renfrew pointed out 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 last years There has been much discussion about C14's supposed half-life of 5,568 years. Today, most scientists agree that Libby was wrong and that the half-life of C14 is actually about 5,730 years. The discrepancy of 162 years becomes significant when dating samples from thousands of years ago.

But along with the Nobel Prize in Chemistry, Libby came to full confidence in his new system. His radiocarbon dating of archaeological samples from Ancient Egypt were already dated because the ancient Egyptians were careful about their chronology. Unfortunately, radiocarbon analysis gave too low an age, in some cases 800 years younger than according to the historical chronicle. But Libby came to a startling conclusion:

“The distribution of the data shows that ancient Egyptian historical dates before the beginning of the second millennium BC are too high and may be 500 years older than the true dates 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; radiocarbon dating had failed him. This problem has now been resolved, but the self-proclaimed reputation of carbon dating still exceeds its reliability.

My research shows that there are two serious problems with radiocarbon dating that can still lead to great misunderstandings today. These are (1) contamination of the samples and (2) changes in atmospheric C14 levels over geological epochs.

Radiocarbon dating standards.

The value of the standard adopted when calculating the radiocarbon age of a sample directly affects the resulting value. According to the results detailed analysis Published literature has established that several standards were used in radiocarbon dating. The most famous of them are the Anderson standard (12.5 dpm/g), the Libby standard (15.3 dpm/g) and the modern standard (13.56 dpm/g).

Dating the pharaoh's boat.

The wood of the pharaoh Sesostris III's boat was radiocarbon dated 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 boat's wood based on the standard (15.3 dpm/g) and obtained a radiocarbon age of 3621 +/-180 BP years. When dating the wood of the boat in 1970, the standard (13.56 dpm/g) was used. The radiocarbon age remained almost unchanged and amounted to 3640 BP years. The factual data we provide on the dating of the pharaoh's boat can be checked using the corresponding links to scientific publications.

Price 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 increases 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 Pharaoh Sesostris III, manipulations were carried out with standards (the wood, contrary to declarations, was dated based on the same standard);

Magic boat of Pharaoh Sesostris III.

Conclusion.

The essence of the phenomena considered, called manipulations, is expressed in one word - falsification.

After death, the C12 content remains constant, but the C14 content decreases

Sample contamination
Mary Levine explains:

“Contamination is the presence in a sample of organic material of foreign origin that was not formed with the sample material.”

Many photographs from the early period of radiocarbon dating show scientists smoking cigarettes while collecting or processing samples. Not too smart of them! As Renfrew points out, “drop a pinch of ash on your samples as they prepare for analysis and you will get the radiocarbon age of the tobacco from which your cigarette was made.”

Although such methodological incompetence is considered unacceptable today, archaeological samples still suffer from contamination. Known types of pollution and methods of controlling them are discussed in the article by Taylor (1987). He divides contaminants into four main categories: 1) physically removable, 2) acid-soluble, 3) alkali-soluble, 4) solvent-soluble. All these contaminants, if not eliminated, greatly affect laboratory determination sample age.

H. E. Gove, one of the inventors of the accelerator mass spectrometry (AMS) method, radiocarbon dated the Shroud of Turin. He concluded that the fabric fibers used to make the shroud dated back to 1325.

Although Gove and his colleagues are quite confident in the authenticity of their determination, many, for obvious reasons, consider the age of the Shroud of Turin to be much more respectable. Gove and his associates gave a fitting response to all the critics, and if I had to make a choice, I would venture to say that the scientific dating of the Shroud of Turin is most likely accurate. But either way, the storm of criticism that has descended on this particular project shows how costly a carbon dating error can be, and how suspicious some scientists are of the method.

It was argued that the samples may have been contaminated by younger organic carbon; cleaning methods may have missed traces of modern contaminants. 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 dates obtained by different laboratories on the Shelford wood sample a “small systematic error”? Doesn't it seem like we are once again being fooled by scientific rhetoric into believing that existing methods are perfect?

Leoncio Garza-Valdez certainly holds this opinion in relation to the dating of the Shroud of Turin. All ancient tissues are covered with a bioplastic film as a result of bacterial activity, which, according to Garza-Valdez, confuses the radiocarbon analyzer. In fact, the Shroud of Turin may well be 2000 years old, since its radiocarbon dating cannot be considered definitive. Further research is needed. It is interesting to note that Gove (although he disagrees with Garza-Valdez) agrees that such criticism warrants new research.

Radiocarbon cycle (14C) in the atmosphere, hydrosphere and biosphere of the Earth

Level C14 in the earth's atmosphere
According to Libby's "principle of simultaneity", the level of C14 in any given geographic region is constant throughout geological history. This premise was vital to the reliability of radiocarbon dating in its early development. Indeed, to reliably measure residual C14 levels, 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 false:

“However, it is now known that the proportional ratio of radiocarbon to ordinary C12 did not remain constant through time and that before 1000 BC the deviations are so great that radiocarbon dates can 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 8,000 years. This means that Libby chose a false constant and his research was based on erroneous assumptions.

Colorado pine, growing in the southwestern regions of the United States, can be several thousand years old. Some trees still alive today were born 4,000 years ago. In addition, using logs collected from the places where these trees grew, it is possible to extend the tree-ring record back another 4,000 years. Other long-lived trees useful for dendrological research include oak and California redwood.

As you know, every year a new growth ring grows on a cut of a living tree trunk. By counting the growth rings, you can find out the age of the tree. It is logical to assume that the level of C14 in a 6000-year-old tree ring would be similar to the level of C14 in the modern atmosphere. But that's not true.

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 now. Accordingly, radiocarbon samples dating to this age were found to be noticeably younger than they actually were, based on dendrological analysis. Thanks to the work of Hans Suisse, C14 level correction charts were compiled to compensate for its fluctuations in the atmosphere in different periods time. However, this significantly reduced the reliability of radiocarbon dating of samples older than 8,000 years. We simply do not have data on the radiocarbon content of the atmosphere before this date.

Accelerator mass spectrometer at the University of Arizona (Tucson, Arizona, USA) manufactured by National Electrostatics Corporation: a – diagram, b – control panel and C¯ ion source, c – accelerator tank, d – carbon isotope detector. Photo by J.S. Burra

When the established “age” differs from what was expected, researchers quickly find a reason to declare the dating result invalid. The widespread prevalence of this posterior evidence shows that radiometric dating has serious problems. Woodmorappe gives hundreds of examples of the tricks researchers resort to when trying to explain “inappropriate” age values.

So, scientists have revised the age of fossil remains Australopithecus ramidus. 9 Most of the basalt samples closest to the strata in which these fossils were found have been given argon-argon ages of about 23 million years. The authors decided that this figure was "too high" based on their understanding of the fossils' place in the global evolutionary scheme. They looked at basalt that was located away from the fossils and, by selecting 17 of 26 samples, came up with an acceptable maximum age of 4.4 million years. The remaining nine samples again showed a much older age, but the experimenters decided that the matter was due to contamination of the rock and rejected these data. Thus, radiometric dating methods are significantly influenced by the dominant “long eras” worldview in scientific circles.

A similar story is associated with establishing the age of a primate skull (this skull is known as specimen KNM-ER 1470).10, 11 The initial result was 212–230 million years, which, based on fossils, was found to be incorrect (“there were no people at that time”), after which attempts were made to establish the age of volcanic rocks in this region. A few years later, after the publication of several different research results, they “agreed” on the figure of 2.9 million years (although these studies also included separating the “good” results from the “bad” - as in the case of Australopithecus ramidus).

Based on preconceived ideas about human evolution, researchers could not come to terms with the idea that the skull 1470 "so old." After studying pig fossils in Africa, anthropologists readily believed that the skull 1470 actually much younger. After the scientific community established itself in this opinion, further studies of rocks further reduced the radiometric age of this skull - to 1.9 million years - and again data was found that “confirmed” another number. This is the “radiometric dating game”...

We do not claim that evolutionists conspired to fit all the data to the most convenient result for themselves. Of course, this is not normally the case. The problem is different: all observational 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 the mind that no one allows himself to question it; on the contrary, they talk about the “fact” of evolution. It is under this paradigm that must fit absolutely all observations. As a result, researchers who appear to the public to be “objective and unbiased scientists” unconsciously cherry-pick observations that are consistent with belief in evolution.

We must not forget that the past is inaccessible to the normal experimental research(series of experiments conducted in the present). Scientists cannot experiment with events that once happened. It is not the age of the rocks that is measured—the concentrations of isotopes are measured, and they can be measured with high accuracy. But “age” is determined taking into account assumptions about the past, which cannot be proven.

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 unwritten history collect information in the present and thus try to reconstruct the past. At the same time, the level of requirements for evidence is much lower than in empirical sciences, such as physics, chemistry, molecular biology, physiology, etc.

William ( Williams), a specialist in the transformation of radioactive elements into environment, identified 17 flaws in isotope dating methods (the results of this dating led to the publication of three very respectable works, 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 debunks hundreds of myths associated with them. He argues convincingly that the few "good" results remaining after the "bad" data have been filtered out can easily be explained by a lucky coincidence.

“What age do you prefer?”

Questionnaires offered by radioisotope laboratories typically ask, “What do you think the age of 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 probably because laboratories are aware of the prevalence of anomalous results and are therefore trying to figure out how “good” the data they are getting is.

Testing 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 exact age; in addition, different methods would produce consistent results.

Dating methods must show reliable results for objects of known age

There are a number of examples where radiometric dating methods incorrectly established the age of rocks (this age was precisely known in advance). One such example is potassium-argon dating of five andesitic lava flows from Mount Ngauruhoe in New Zealand. Although the lava was known to flow once in 1949, three times in 1954, and once again in 1975, the "established ages" ranged from 0.27 to 3.5 million years.

The same retrospective method gave rise to the following explanation: when the rock hardened, there was “extra” argon left in it due to magma (molten rock). The secular scientific literature provides numerous examples of how excess argon results in “extra millions of years” when dating rocks of known historical age.14 The source of excess argon appears to be the Earth's upper mantle, located just below the Earth's crust. This is quite consistent with the “young Earth” theory - the argon had too little time, it simply did not have time to be released. But if an excess of argon led to such glaring errors in dating rocks famous age, why should we trust the same method when dating rocks whose age unknown?!

Other methods—particularly 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. Here again, the choice of data is based on the researcher's assumption about the age of a particular breed.

Dr. Steve Austin (Steve Austin), a geologist, sampled basalt from the lower layers of the Grand Canyon and from lava flows at the canyon rim.17 By evolutionary logic, the basalt at the canyon rim should be a billion years younger than the basalt in the depths. Standard laboratory isotope analysis using rubidium-strontium isochron dating showed that the lava flow was relatively recent at 270 million years ago. older basalt from the depths of the Grand Canyon - which, of course, is absolutely impossible!

Methodological problems

Initially, Libby's idea was based on the following hypotheses:

1. 14C is formed in the upper layers of the atmosphere under the influence of cosmic rays, then mixed in the atmosphere, becoming part of carbon dioxide. Moreover, the percentage of 14C in the atmosphere is constant and does not depend on time or place, despite the heterogeneity of the atmosphere itself and the decay of isotopes.
2. The rate of radioactive decay is a 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).
3. Animal and plant organisms build their bodies from carbon dioxide extracted from the atmosphere, and living cells contain the same percentage of the 14C isotope that is found in the atmosphere.
4. Upon the death of an organism, its cells leave the carbon metabolism cycle, but atoms of the 14C isotope continue to transform into atoms of the stable 12C isotope according to the exponential law of radioactive decay, which allows us to calculate the time that has passed since the death of the organism. This time is called “radiocarbon age” (or “RU age” for short).

This theory, as material accumulated, began to have counterexamples: the analysis of recently deceased organisms sometimes gives very ancient age, or, conversely, the sample contains such a huge amount of the isotope that the calculations give a negative RU age. Some obviously ancient objects had a young RU age (such artifacts were declared to be late fakes). 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 X-ray method is used to date organic objects of unknown age, and the X-ray dating cannot be verified. Cases of erroneous determination of age are explained by the following well-known shortcomings of Libby's theory (these and other factors are analyzed in the book by M. M. Postnikov "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 in 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 combustion and decay of ancient organic matter, the emergence of new sources of radioactivity, and 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 rate of atmospheric mixing does not exclude the possibility of significant differences in 14C content in different geographic regions.
3. The rate of radioactive decay of isotopes may not be determined accurately. So, since the time of Libby, the half-life of 14C according to official reference books has “changed” by a hundred years, that is, by a couple of percent (this corresponds to a change in the RU-age of one and a half hundred years). It is suggested that the half-life value depends significantly (within a few percent) 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 atom of 14C to 10 billion atoms of 12C), even a slight isotopic selectivity of a cell entails a large change in the RU age (a 10% fluctuation leads to an error of approximately 600 years).
5. After 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 of an item may not be uniform. Since Libby's time, radiocarbon physicists have become very precise at determining the isotope content of a sample; They even claim that they are able to count 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 entire object? How uniform is the isotope content in it? After all, errors of a few percent lead to century-long changes in the RU-age.

Summary
Radiocarbon dating is an evolving scientific method. However, at every stage of its development, scientists unconditionally supported its overall reliability and fell silent only after revealing serious errors in the estimates or in the method of analysis itself. The errors shouldn't 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 a representative archaeological survey, radiocarbon dating remains of utmost importance; it just needs to be placed into cultural and historical perspective. Does a scientist have the right to discount contradictory archaeological evidence just because his carbon dating indicates a different age? Is it dangerous. In fact, many Egyptologists supported Libby's suggestion that the Old Kingdom chronology was incorrect because it had been "scientifically proven." Libby was actually wrong.

Radiocarbon dating is useful as a complement to other data, and this is where it comes from. strong point. But until the day comes when all variables are under control and all errors are eliminated, radiocarbon dating will not have the final word on archaeological sites.
sources
Chapter from the book by K. Ham, D. Sarfati, K. Wieland, ed. D. Batten
Graham Hancock: . M., 2006. Pp. 692-707.

05.05.2017

Is radiocarbon dating reliable?

The most popular is the radiocarbon method, which claims to independently date ancient monuments. However, as radiocarbon dates accumulated, the most serious difficulties in applying the method were revealed, in particular, as A. Oleinikov writes, “we had to think about one more problem. The intensity of radiation penetrating the atmosphere varies depending on many cosmic reasons. Therefore, the amount of radioactive isotope produced carbon must fluctuate over time. It is necessary to find a way that would allow them to be taken into account. In addition, huge amounts of carbon generated by the combustion of wood fuel, coal, oil, peat, oil shale and their products are continuously released into the atmosphere. What is the impact does this source of atmospheric carbon increase the content of the radioactive isotope? In order to achieve a determination of the true age, complex corrections will have to be calculated to reflect changes in the composition of the atmosphere over time last millennium. These ambiguities, along with some technical difficulties, have raised doubts about the accuracy of many determinations made by the carbon method."

The author of the method, W. F. Libby (not being a historian), was absolutely confident in the correctness of Scaligerian dating, and from his book it is clear that it was precisely according to them that the radiocarbon method was adjusted. However, archaeologist Vladimir Milojcic has convincingly shown that this method in its current state gives chaotic errors of up to 1000 - 2000 years and in its “independent” dating of ancient samples slavishly follows the dating proposed by historians, and therefore it is impossible to say that it “confirms” it .

Here are some instructive details. As already noted, W. F. Libby was a priori confident in the correctness of the Scaligerian dating of ancient events. He wrote: “We had no disagreement with historians regarding Ancient Rome and Ancient Egypt. WE DID NOT CARRY OUT NUMEROUS DETERMINATIONS ON THIS ERA, since in general its chronology is known to archeology better than we could establish it and, by providing samples at our disposal, archaeologists were rather doing us a favor."

This recognition by Libby is significant, since the difficulties of Scaligerian chronology were discovered precisely for those regions and eras for which, as Libby told us, “numerous determinations were not made.” With the same small number of control measurements (from antiquity), which were nevertheless carried out, the situation is as follows: during radiocarbon dating, for example, the collection of J.H. Brasted (Egypt), “suddenly it was discovered,” reports Libby, “that the third object ", which we analyzed turned out to be modern! It was one of the finds... that was considered... belonging to the dynasty. Yes, it was a heavy blow."

However, a “way out” was immediately found: the object was declared a forgery, since no one had the idea to doubt the correctness of the Scaligerian chronology of Ancient Egypt.

“In support of their fundamental assumption, they (i.e., supporters of the method - Comp.) cite a number of indirect evidence, considerations and calculations, the accuracy of which is low, and the interpretation is ambiguous, and the main evidence is control radiocarbon determinations of samples of a previously known age... But As soon as we talk about control dating of historical objects, everyone refers to the first experiments, i.e. to a small series of samples.”

The absence (as Libby also admits) of extensive control statistics, and even in the presence of the millennia-long discrepancies in dating noted above ("explained" by forgeries), calls into question the possibility of using the method in the time interval of interest to us. This does not apply to applications of the method for geological purposes, where errors of several thousand years are insignificant.

W. F. Libby wrote: “However, we did not feel a lack of materials from an era 3700 years distant from us, on which the accuracy and reliability of the method could be tested (however, there is nothing to compare radiocarbon dates with, since there are no dated written sources of these eras - Comp.)... Historians I know are READY TO VOUNT for the accuracy (of dating - Comp.) within the last 3750 years, however, when it comes to more ancient events, their confidence disappears."

In other words, the radiocarbon method has been widely used where (with a sigh of relief) the results obtained are difficult (and practically impossible) to verify by other independent methods.

“Some archaeologists, without doubting the scientific principles of the radiocarbon method, have suggested that the method itself harbors the possibility of significant errors caused by as yet unknown effects.” But maybe these errors are still small and do not interfere with at least rough dating (in the range of 2-3 thousand years “down” from our time)? However, it turns out that the situation is more serious. The errors are too big and chaotic. They can reach a value of 1-2 thousand years when dating objects of our time and the Middle Ages (see below).

The magazine "Technology and Science", 1984, issue 3, p. 9, reported the results of the discussion that unfolded around the radiocarbon method at two symposiums in Edinburgh and Stockholm: "In Edinburgh, examples of hundreds (!) of analyzes were given in which dating errors ranged from 600 to 1800 years. In Stockholm, scientists complained that the radiocarbon method for some reason especially distorts the history of Ancient Egypt in an era 4000 years distant from us. There are other cases, for example, in the history of the Balkan civilizations... Experts in One voice said that the radiocarbon method is still doubtful because it lacks calibration. Without this, it is unacceptable, because it does not give true dates on the calendar scale."

Radiocarbon dates brought, as L.S. Klein writes, “confusion in the ranks of archaeologists. Some with characteristic admiration... accepted the instructions of physicists... These archaeologists hastened to rebuild the chronological schemes... The first archaeologist to speak out against the radiocarbon method was Vladimir Miloichich ... who... not only attacked the practical application of radiocarbon dating, but also... severely criticized the very theoretical premises of the physical method... Comparing individual measurements of modern samples with the average figure - the standard, Milojcic justifies his skepticism with a series of brilliant paradoxes .

The shell of a LIVING American mollusk with a radioactivity of 13.8, when compared with the average figure as an absolute norm (15.3), turns out to be already today (translated into years) at a respectable age - it is about 1200 years old! BLOOMING wild rose from North Africa(radioactivity 14.7) has been “dead” for physicists for 360 years... and the Australian eucalyptus, whose radioactivity is 16.31, does not yet “exist” for them - it WILL only EXIST in 600 years. The Florida shell, which recorded 17.4 decays per minute per gram of carbon, will not “emerge” until 1080 years later...

But since in the past radioactivity was not distributed more evenly than now, similar fluctuations and errors should be recognized as possible for ancient objects. And here are some clear facts: radiocarbon dating in Heidelberg of a sample from a medieval altar... showed that the tree used to repair the altar had not yet grown at all!... In the Welt Cave (Iran) the underlying layers are dated 6054 (plus or minus 415 ) and 6595 (plus or minus 500) BC, and the overlying one - 8610 (plus or minus 610) BC. Thus... the sequence of layers is reversed and the overlying one turns out to be 2556 years older than the underlying one! And there are countless examples like this..."

So, the radiocarbon dating method is applicable for rough dating only those objects whose age is several tens of thousands of years. His errors in dating specimens one or two thousand years old are COMPARABLE TO THIS AGE ITSELF. That is, sometimes they reach a THOUSAND or more years.

Here are some more striking examples.

1) LIVING shellfish were “dated” using radiocarbon dating. The results of the analysis showed their “age”: supposedly 2300 years. These data were published in the journal Science, issue 130, December 11, 1959. The error is TWO THOUSAND THREE HUNDRED years.

2) Nature, issue 225, March 7, 1970, reports that a carbon-14 test was carried out on organic material from the mortar of an English castle. It is known that the castle was built 738 years ago. However, radiocarbon “dating” gave an “age” - supposedly 7370 years. The error is SIX AND A HALF THOUSAND YEARS. Was it worth giving the date accurate to 10 years?

3) JUST shot seals were “dated” by their carbon-14 content. Their “age” was determined to be 1300 years! A mistake of THOUSAND THREE HUNDRED YEARS. And the mummified corpses of seals that died just 30 years ago have been “dated” to be supposedly 4,600 years old. The error is FOUR AND A HALF THOUSAND YEARS. These results were published in the Antarctic Journal of the United States, issue 6, 1971.

In these examples, radiocarbon "dating" ADDES THE AGE OF THE SAMPLES BY THOUSANDS OF YEARS. As we have seen, there are counterexamples where radiocarbon "dating" not only DECREASES the age, but even "transports" the sample INTO THE FUTURE.

Is it any wonder that in many cases radiocarbon “dating” pushes medieval objects into deep antiquity.

L.S. Klein continues: “Miloichich calls for, finally, to abandon the “critical” EDITING of the results of radiocarbon measurements by physicists and their “customers” - archaeologists, to abolish the “critical” CENSORSHIP when publishing the results. Physicists Miloichich asks NOT TO SELECT DATES that for some reason - it seems incredible to archaeologists to publish all the results, all the measurements, without selection.

Milojchich persuades archaeologists to put an end to the tradition of PRELIMINARY Familiarization of PHYSICISTS with the approximate age of a find (before its radiocarbon determination) - not to give them any information about the find until they publish their figures! Otherwise, it is impossible to establish how many radiocarbon dates coincide with reliable historical ones, i.e. it is impossible to determine the degree of reliability of the method. In addition, with such “editing” the very results of dating - the appearance of the resulting chronological scheme - are affected by the subjective views of researchers.

For example, in Groningen, where the archaeologist Becker has long adhered to a short chronology, and radiocarbon dates “for some reason” turn out to be low, while in Schleswig and Heidelberg, where Schwabdissen and others have long been inclined to long chronology, and the radiocarbon dates of similar materials turn out to be much more high."

In our opinion, any comments here are unnecessary: ​​the picture is absolutely clear.

In 1988, a message about radiocarbon dating of the famous Christian shrine - the Shroud of Turin - received a great response. According to the traditional version, this piece of fabric contains traces of the body of the crucified Christ (1st century AD), i.e. The age of the fabric is supposedly about two thousand years. However, radiocarbon dating gave a completely different date: approximately XI-XIII centuries AD. What's the matter? Naturally, the following conclusions arise:

Either the Shroud of Turin is a fake,
or radiocarbon dating errors can reach many hundreds or even thousands of years,
or the Shroud of Turin is an original, but dating not from the 1st century AD, but from the 11th-13th centuries AD. (but then another question arises - in what century did Christ live?).

As we can see, radiocarbon dating is perhaps more or less effective only when analyzing extremely ancient objects, whose age reaches tens or hundreds of thousands of years. Here, the inherent errors of several thousand years in the method are perhaps not so significant. However, the mechanical application of the method for dating objects whose age does not exceed two thousand years (namely, this historical era is most interesting for restoring the true chronology of written civilization!) seems to us unthinkable without conducting preliminary detailed statistical and calibration studies on samples of reliably known age. At the same time, it is completely unclear in advance whether it is even possible in principle to increase the accuracy of the method to the required limits.

G. V. Nosovsky, A. T. Fomenko, Mathematical chronology of biblical events

May 12th, 2013

Everything that has come down to us from paganism is shrouded in thick fog; it belongs to that interval of burden which we cannot measure. We know that it is older than Christianity, but by two years, two hundred years or a whole millennium - here we can only guess. Rasmus Nierup, 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 has important implications for different and independent scientific disciplines such as hydrology, geology, atmospheric science and archaeology. However, we leave the understanding of the principles of radiocarbon dating to the scientific experts and blindly accept their conclusions out of respect for the accuracy of their equipment and admiration for their intelligence.

In fact, the principles of radiocarbon dating are amazingly simple and easily accessible. Moreover, the idea of ​​carbon dating as an “exact science” is misleading, and in truth, few scientists hold this opinion. The problem is that representatives of many disciplines who use radiocarbon dating for chronological purposes do not understand its nature and purpose. Let's look into this.

Principles of Radiocarbon Dating

William Frank Libby and members of his team developed the principles of radiocarbon dating in the 1950s. By 1960, their work was complete, and in December of that year, Libby was nominated for the Nobel Prize in Chemistry. One of the scientists involved in his nomination noted:

“It has rarely happened that one discovery in the field of chemistry has 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%.

Stable carbon isotopes 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 bombardment of the solar atmosphere by cosmic rays. When cosmic rays collide with certain atoms, they destroy them, as a result of which the neutrons of these atoms become free in the earth's atmosphere.

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 C14 atoms, which are formed at a constant rate, undergo oxidation and penetrate into the biosphere through the process of photosynthesis and the natural food chain.

In the organisms of all living beings, the ratio of C12 and C14 isotopes is equal to the atmospheric ratio of these isotopes in their geographical region and is maintained by the rate of their metabolism. However, after death, organisms stop accumulating carbon, and the behavior of the C14 isotope from this point on becomes interesting. Libby found that the half-life of C14 was 5568 years; After another 5568 years, half of the remaining atoms of the isotope decay.

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 an age of 10,146 years.

This is the basic principle of radiocarbon dating as an archaeological tool. Radiocarbon is absorbed into the biosphere; it stops accumulating with the death of the organism and decays at a certain rate that can be measured.

In other words, the C 14 / C 12 ratio gradually decreases. Thus, we get a “clock” that begins to tick from the moment of death of a living being. Apparently this clock only works on dead bodies that were once living beings. For example, they cannot be used to determine the age of volcanic rocks.

The decay rate of C 14 is such that half of this substance turns back into N 14 within 5730 ± 40 years. This is the so-called “half-life”. After 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 one-quarter that of modern living organisms, the sample is theoretically 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 ages of millions of years. If the sample contains C14, this already indicates that its age less million years.

However, everything is not so simple. Firstly, plants absorb carbon dioxide containing C14 worse. Consequently, they accumulate less of it than expected and therefore appear older than they actually are when tested. Moreover, different plants assimilate C14 in different ways, and allowances should be made for this too. 2

Secondly, the ratio of C 14 /C 12 in the atmosphere was not always constant - for example, it decreased with the onset of the industrial era, when, due to the combustion of huge quantities of organic fuel, a mass of carbon dioxide depleted in C 14 was released. Accordingly, organisms that died during this period appear older under radiocarbon dating. Then there was an increase in C14O2 associated with above-ground nuclear testing in the 1950s, 3 causing organisms that died during this period 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 indicating the date of burial) make it possible to estimate the level of C14 in the atmosphere at that time and, thus, partially “correct the progress” of the radiocarbon “clock”. Accordingly, radiocarbon dating, carried out taking into account historical data, can give very fruitful results. However, even with this “historical setting,” archaeologists do not consider radiocarbon dates to be absolute, due to frequent anomalies. They rely more on dating methods associated with historical records.

Outside of historical data, “setting” the “clock” from 14 is not possible

In the laboratory

Given all these irrefutable facts, it is extremely strange to see the following statement in the journal Radiocarbon (which publishes the results of radiocarbon studies around the world):

“Six reputable laboratories carried out 18 age analyzes on wood from Shelford in Cheshire. Estimates range from 26,200 to 60,000 years (before the present), with a range of 34,600 years."

Here's another fact: Although the theory of radiocarbon dating sounds convincing, when its principles are applied to laboratory samples, human factors come into play. This leads to errors, sometimes very significant ones. In addition, laboratory samples are contaminated by background radiation, altering the residual level of C14 that is measured.

As Renfrew pointed out 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 much discussion about C14's supposed half-life of 5,568 years. Today, most scientists agree that Libby was wrong and that the half-life of C14 is actually about 5,730 years. The discrepancy of 162 years becomes significant when dating samples from thousands of years ago.

But along with the Nobel Prize in Chemistry, Libby came to full confidence in his new system. His radiocarbon dating of archaeological samples from ancient Egypt had already been dated because the ancient Egyptians were careful about their chronology. Unfortunately, radiocarbon analysis gave too low an age, in some cases 800 years younger than according to the historical chronicle. But Libby came to a startling conclusion:

“The distribution of the data shows that ancient Egyptian historical dates before the beginning of the second millennium BC are too high and may be 500 years older than the true dates 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; radiocarbon dating had failed him. This problem has now been resolved, but the self-proclaimed reputation of carbon dating still exceeds its reliability.

My research shows that there are two serious problems with radiocarbon dating that can still lead to great misunderstandings today. These are (1) contamination of the samples and (2) changes in atmospheric C14 levels over geological epochs.

Radiocarbon dating standards. The value of the standard adopted when calculating the radiocarbon age of a sample directly affects the resulting value. Based on the results of a detailed analysis of the published literature, it was established that several standards were used in radiocarbon dating. The most famous of them are the Anderson standard (12.5 dpm/g), the Libby standard (15.3 dpm/g) and the modern standard (13.56 dpm/g).

Dating the pharaoh's boat. The wood of the pharaoh Sesostris III's boat was radiocarbon dated 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 boat's wood based on the standard (15.3 dpm/g) and obtained a radiocarbon age of 3621 +/-180 BP years. When dating the wood of the boat in 1970, the standard (13.56 dpm/g) was used. The radiocarbon age remained almost unchanged and amounted to 3640 BP years. The factual data we provide on the dating of the pharaoh's boat can be checked using the corresponding links to scientific publications.

Price 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 increases 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 Pharaoh Sesostris III, manipulations were carried out with standards (the wood, contrary to declarations, was dated based on the same standard);

Magic boat of Pharaoh Sesostris III.

Conclusion. The essence of the phenomena considered, called manipulations, is expressed in one word - falsification.

After death, the C 12 content remains constant, and the C 14 content decreases

Sample contamination

Mary Levine explains:

“Contamination is the presence in a sample of organic material of foreign origin that was not formed with the sample material.”

Many photographs from the early period of radiocarbon dating show scientists smoking cigarettes while collecting or processing samples. Not too smart of them! As Renfrew points out, “drop a pinch of ash on your samples as they prepare for analysis and you will get the radiocarbon age of the tobacco from which your cigarette was made.”

Although such methodological incompetence is considered unacceptable today, archaeological samples still suffer from contamination. Known types of pollution and methods of controlling them are discussed in the article by Taylor (1987). He divides contaminants into four main categories: 1) physically removable, 2) acid-soluble, 3) alkali-soluble, 4) solvent-soluble. All these contaminants, if not eliminated, greatly affect the 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 Shroud of Turin. He concluded that the fabric fibers used to make the shroud dated back to 1325.

Although Gove and his colleagues are quite confident in the authenticity of their determination, many, for obvious reasons, consider the age of the Shroud of Turin to be much more respectable. Gove and his associates gave a fitting response to all the critics, and if I had to make a choice, I would venture to say that the scientific dating of the Shroud of Turin is most likely accurate. But either way, the storm of criticism that has descended on this particular project shows how costly a carbon dating error can be, and how suspicious some scientists are of the method.

It was argued that the samples may have been contaminated by younger organic carbon; cleaning methods may have missed traces of modern contaminants. 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 dates obtained by different laboratories on the Shelford wood sample a “small systematic error”? Doesn't it seem like we are once again being fooled by scientific rhetoric into believing that existing methods are perfect?

Leoncio Garza-Valdez certainly holds this opinion in relation to the dating of the Shroud of Turin. All ancient tissues are covered with a bioplastic film as a result of bacterial activity, which, according to Garza-Valdez, confuses the radiocarbon analyzer. In fact, the Shroud of Turin may well be 2000 years old, since its radiocarbon dating cannot be considered definitive. Further research is needed. It is interesting to note that Gove (although he disagrees with Garza-Valdez) agrees that such criticism warrants new research.

Radiocarbon cycle (14C) in the atmosphere, hydrosphere and biosphere of the Earth

Level C14 in the earth's atmosphere

According to Libby's "principle of simultaneity", the level of C14 in any given geographic region is constant throughout geological history. This premise was vital to the reliability of radiocarbon dating in its early development. Indeed, to reliably measure residual C14 levels, 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 false:

“However, it is now known that the proportional ratio of radiocarbon to ordinary C12 did not remain constant through time and that before 1000 BC the deviations are so great that radiocarbon dates can 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 8,000 years. This means that Libby chose a false constant and his research was based on erroneous assumptions.

Colorado pine, growing in the southwestern regions of the United States, can be several thousand years old. Some trees still alive today were born 4,000 years ago. In addition, using logs collected from the places where these trees grew, it is possible to extend the tree-ring record back another 4,000 years. Other long-lived trees useful for dendrological research include oak and California redwood.

As you know, every year a new growth ring grows on a cut of a living tree trunk. By counting the growth rings, you can find out the age of the tree. It is logical to assume that the level of C14 in a 6000-year-old tree ring would be similar to the level of C14 in the modern atmosphere. But that's not true.

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 now. Accordingly, radiocarbon samples dating to this age were found to be noticeably younger than they actually were, based on dendrological analysis. Thanks to the work of Hans Suisse, C14 level correction charts were compiled to compensate for its fluctuations in the atmosphere over different periods of time. However, this significantly reduced the reliability of radiocarbon dating of samples older than 8,000 years. We simply do not have data on the radiocarbon content of the atmosphere before this date.

Accelerator mass spectrometer at the University of Arizona (Tucson, Arizona, USA) manufactured by National Electrostatics Corporation: a – diagram, b – control panel and C¯ ion source, c – accelerator tank, d – carbon isotope detector. Photo by J.S. Burra

About installations.

"Bad" results?

When the established “age” differs from what was expected, researchers quickly find a reason to declare the dating result invalid. The widespread prevalence of this posterior evidence shows that radiometric dating has serious problems. Woodmorappe gives hundreds of examples of the tricks researchers resort to when trying to explain “inappropriate” age values.

So, scientists have revised the age of fossil remains Australopithecus ramidus. 9 Most of the basalt samples closest to the strata in which these fossils were found have been given argon-argon ages of about 23 million years. The authors decided that this figure was "too high" based on their understanding of the fossils' place in the global evolutionary scheme. They looked at basalt that was located away from the fossils and, by selecting 17 of 26 samples, came up with an acceptable maximum age of 4.4 million years. The remaining nine samples again showed a much older age, but the experimenters decided that the matter was due to contamination of the rock and rejected these data. Thus, radiometric dating methods are significantly influenced by the dominant “long eras” worldview in scientific circles.

A similar story is associated with establishing the age of the primate skull (this skull is known as specimen KNM-ER 1470). 10, 11 Initially, a result of 212–230 million years was obtained, which, based on fossils, was found to be incorrect (“there were no people at that time”), after which attempts were made to establish the age of volcanic rocks in this region. A few years later, after the publication of several different research results, they “agreed” on the figure of 2.9 million years (although these studies also included separating the “good” results from the “bad” - as in the case of Australopithecus ramidus).

Based on preconceived ideas about human evolution, researchers could not come to terms with the idea that the skull 1470 "so old." After studying pig fossils in Africa, anthropologists readily believed that the skull 1470 actually much younger. After the scientific community established itself in this opinion, further studies of rocks further reduced the radiometric age of this skull - to 1.9 million years - and again data was found that “confirmed” another number. This is the “radiometric dating game”...

We do not claim that evolutionists conspired to fit all the data to the most convenient result for themselves. Of course, this is not normally the case. The problem is different: all observational 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 the mind that no one allows himself to question it; on the contrary, they talk about the “fact” of evolution. It is under this paradigm that must fit absolutely all observations. As a result, researchers who appear to the public to be “objective and unbiased scientists” unconsciously cherry-pick observations that are consistent with belief in evolution.

We must not forget that the past is inaccessible to normal experimental research (a series of experiments conducted in the present). Scientists cannot experiment with events that once happened. It is not the age of the rocks that is measured—the concentrations of isotopes are measured, and they can be measured with high accuracy. But “age” is determined taking into account assumptions about the past, which cannot be proven.

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 unwritten history collect information in the present and thus try to reconstruct the past. At the same time, the level of requirements for evidence is much lower than in empirical sciences, such as physics, chemistry, molecular biology, physiology, etc.

William ( Williams), a specialist in the transformations of radioactive elements in the environment, identified 17 flaws in isotope dating methods (based on the results of this dating, three very respectable 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 methods 8 and debunks hundreds of myths associated with them. He argues convincingly that the few "good" results remaining after the "bad" data have been filtered out can easily be explained by a lucky coincidence.

“What age do you prefer?”

Questionnaires offered by radioisotope laboratories typically ask, “What do you think the age of 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 probably because laboratories are aware of the prevalence of anomalous results and are therefore trying to figure out how “good” the data they are getting is.

Testing 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 exact age; in addition, different methods would produce consistent results.

Dating methods must show reliable results for objects of known age

There are a number of examples where radiometric dating methods incorrectly established the age of rocks (this age was precisely known in advance). One such example is potassium-argon dating of five andesitic lava flows from Mount Ngauruhoe in New Zealand. Although the lava was known to flow once in 1949, three times in 1954, and once again in 1975, the "established ages" ranged from 0.27 to 3.5 million years.

The same retrospective method gave rise to the following explanation: when the rock hardened, there was “extra” argon left in it due to magma (molten rock). The secular scientific literature provides many examples of how excess argon leads to “extra millions of years” when dating rocks of known historical age. 14 The source of excess argon appears to be the upper part of the Earth's mantle, located directly below the Earth's crust. This is quite consistent with the “young Earth” theory - the argon had too little time, it simply did not have time to be released. But if an excess of argon led to such glaring errors in dating rocks famous age, why should we trust the same method when dating rocks whose age unknown?!

Other methods—particularly 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. Here again, the choice of data is based on the researcher's assumption about the age of a particular breed.

Dr. Steve Austin (Steve Austin), a geologist, took samples of basalt from the lower layers of the Grand Canyon and from lava flows at the canyon rim. 17 According to evolutionary logic, the basalt at the edge of the canyon should be a billion years younger than the basalt from the depths. Standard laboratory isotope analysis using rubidium-strontium isochron dating showed that the lava flow was relatively recent at 270 million years ago. older basalt from the depths of the Grand Canyon - which, of course, is absolutely impossible!

Methodological problems

Initially, Libby's idea was based on the following hypotheses:

1. 14C is formed in the upper layers of the atmosphere under the influence of cosmic rays, then mixed in the atmosphere, becoming part of carbon dioxide. Moreover, the percentage of 14C in the atmosphere is constant and does not depend on time or place, despite the heterogeneity of the atmosphere itself and the decay of isotopes.
2. The rate of radioactive decay is a 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).
3. Animal and plant organisms build their bodies from carbon dioxide extracted from the atmosphere, and living cells contain the same percentage of the 14C isotope that is found in the atmosphere.
4. Upon the death of an organism, its cells leave the carbon metabolism cycle, but atoms of the 14C isotope continue to transform into atoms of the stable 12C isotope according to the exponential law of radioactive decay, which allows us to calculate the time that has passed since the death of the organism. This time is called “radiocarbon age” (or “RU age” for short).

This theory, as material accumulated, began to have counterexamples: analysis of recently deceased organisms sometimes gives a very ancient age, or, conversely, a sample contains such a huge amount of an isotope that calculations give a negative RU age. Some obviously ancient objects had a young RU age (such artifacts were declared to be late fakes). 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 X-ray method is used to date organic objects of unknown age, and the X-ray dating cannot be verified. Cases of erroneous determination of age are explained by the following well-known shortcomings of Libby's theory (these and other factors are analyzed in the book by M. M. Postnikov "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 combustion and decay of ancient organic matter, the emergence of new sources of radioactivity, and 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. The uniform distribution of 14C in the atmosphere has not been proven. The rate of atmospheric mixing does not exclude the possibility of significant differences in 14C content in different geographic regions.
3. The rate of radioactive decay of isotopes may not be determined entirely accurately. So, since the time of Libby, the half-life of 14C according to official reference books has “changed” by a hundred years, that is, by a couple of percent (this corresponds to a change in the RU-age of one and a half hundred years). It is suggested that the half-life value depends significantly (within a few percent) 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 atom of 14C to 10 billion atoms of 12C), even a slight isotopic selectivity of a cell entails a large change in the RU age (a 10% fluctuation leads to an error of approximately 600 years).
5. After 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 of an item may not be uniform. Since Libby's time, radiocarbon physicists have become very precise at determining the isotope content of a sample; They even claim that they are able to count 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 entire object? How uniform is the isotope content in it? After all, errors of a few percent lead to century-long changes in the RU-age.

Summary

Radiocarbon dating is an evolving scientific method. However, at every stage of its development, scientists unconditionally supported its overall reliability and fell silent only after revealing serious errors in the estimates or in the method of analysis itself. The errors shouldn't 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 a representative archaeological survey, radiocarbon dating remains of utmost importance; it just needs to be placed into cultural and historical perspective. Does a scientist have the right to discount contradictory archaeological evidence just because his carbon dating indicates a different age? Is it dangerous. In fact, many Egyptologists supported Libby's suggestion that the Old Kingdom chronology was incorrect because it had been "scientifically proven." Libby was actually wrong.

Radiocarbon dating is useful as a complement to other data, and this is its strength. But until the day comes when all variables are under control and all errors are eliminated, radiocarbon dating will not have the final word on archaeological sites.
sources Chapter from the book by K. Ham, D. Sarfati, K. Wieland, ed. D. Batten “BOOK OF ANSWERS: EXTENDED AND UPDATED”
Graham Hancock: Footprints of the Gods. M., 2006. Pp. 692-707.

Including for these reasons described above, mysteries “pop up” and arise. The original article is on the website InfoGlaz.rf Link to the article from which this copy was made -